Beep in shell script not working?

Question: I'd like to use a beep sound in a shell script. Unfortunately none of the methods I found via Google work for me.
I tried
echo -e '\a'

echo -ne '\007'

and the command beep after I installed it via apt.
What could be the reason?
Comment: See this bug report: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/769314
Comment: http://superuser.com/questions/47564/remotely-make-the-computer-beep-on-built-in-speaker || http://unix.stackexchange.com/questions/1974/how-do-i-make-my-pc-speaker-beep || http://stackoverflow.com/questions/10313939/how-to-emit-a-beep-on-my-computer-while-running-a-script-on-a-remote-machine
Comment: ### For a Nice PulseAudio Bell Sound in Xubuntu ###
See: https://askubuntu.com/questions/1310345/how-to-fix-gnome-terminal-bell-in-xubuntu-20-04
Comment: If your terminal is `terminator`, see my Q&A here for the answer: https://askubuntu.com/questions/1253799/terminator-terminal-wont-play-bell-sound/1253800#1253800.
Answer: Not being a fan of the pcspkr beep, I use a beep from one of the system sounds with the installed pulseaudio server's paplay command.
First find a sound you like (you can browse /usr/share/sounds for some available ones for example) and create a reference to it
export BEEP=/usr/share/sounds/ubuntu/ringtones/Harmonics.ogg

Then have it available as a command
alias beep='paplay $BEEP'

Now just run beep whenever you need it. For example, to alert you when a command is finished:
find . | grep treasure ; beep

Comment: This is a great solution! Now I can do `run-my-long-test-suite.sh; beep` and read stackoverflow until the system is ready.
Comment: Playing these ogg files can result in latency orders of magnitude greater than that of the internal PC speaker beep. Not only that the latency seems highly variable. I acknowledge that most people don't care but when you need real time or near real time responsiveness the PC speaker is probably the best option for audible feedback.
Comment: Nice! I use `export BEEP=/usr/share/sounds/ubuntu/stereo/dialog-information.ogg` and `alias beep='paplay $BEEP --volume=32768'` now, that works well for me. (Note that you can override the volume with the `beep` alias, e.g. `beep --volume=15000` plays at volume of -12dB.)
Comment: Can you get it to play this sound when someone runs `echo -e '\a'`
Comment: You might need some [read](http://stackoverflow.com/questions/9731281/bash-script-listen-for-key-press-to-move-on) command in a while loop or some other library that can monitore keystrokes.
Comment: This does not answer the question at all
Comment: If you like this, you might also like `spd-say "Analysis complete"`
Comment: Unfortunately this approach doesn't work if I want to trigger a beep sound in an SSH session (i.e. from a command in a remote server). However, if I could get the `echo` command to work, then it would be possible: https://serverfault.com/questions/500839/let-the-local-machine-beep-when-some-event-happen-on-remote
Answer: First run sudo modprobe pcspkr and then beep should work.
The reason this doesn't is because by default Ubuntu no longer loads the hardware driver that produce beeps.
If this works for you then to enable the loading of pcspkr permanently edit the /etc/modprobe.d/blacklist.conf file (using gksudo gedit perhaps) and comment out line that says blacklist pcspkr so it looks like this:
# ugly and loud noise, getting on everyone's nerves; this should be done by a
# nice pulseaudio bing (Ubuntu: #77010)
# blacklist pcspkr
Comment: This doesn't work for me in Ubuntu 14.
Comment: If I comment `blacklist pcspkr` I have to do `modprobe -r pcspkr && modprobe pcspkr` to get it to work. Also getting beep to work is _not_ the same as getting the audible bell to work and thus http://askubuntu.com/questions/22168/how-do-i-enable-the-terminal-bell should still be open.
Comment: This will mostly likely never work on modern laptops, as they don't have a speaker device.  Instead see my answer below on how to use `paplay`.  (I wasted a bunch of time chasing down this, only to get silence.)
Answer: Since this is a very high rated question on google, I'll add the steps I did to re-enable beep in both console and X11:

For the Linux Console (CTRL+ALT+F1...F6):
Why it does not work by default
As already answered, the pcspkr kernel driver for the PC Speaker is blacklisted in Ubuntu.
Temporarily enable until reboot:
sudo modprobe pcspkr

Automatically enable on boot:
sudo nano /etc/modprobe.d/blacklist.conf

(delete or comment pcspkr line by prepending it with #)

For X11 terminals (such as the default gnome-terminal)
Why it does not work by default
Under X, like when using Unity, KDE, Gnome Shell, the beep events are captured by PulseAudio thanks to module-x11-bell, which is loaded by default at /usr/bin/start-pulseaudio-x11. And the sound sample PulseAudio plays on beep, bell.ogg, is blank by default. Additionally, the bell volume may be muted.
To temporarily enable for current session,
xset b 100  # perhaps not needed, on my system it was 40 by default
pactl upload-sample /usr/share/sounds/ubuntu/stereo/bell.ogg bell.ogg

There are other suitable samples you can try at /usr/share/sounds, for example check the ones at /usr/share/sounds/gnome/default/alerts/
Note that the beep program is not really necessary. But if installed, it uses the PC Speaker. It was the only way I could find to enable the buzzer under X:
sudo apt-get install beep

To automatically enable on boot, just add the above lines in your ~/.profile, or system-wide at /etc/profile

To test it:
printf '\a'

Beep!
beep

Buzz!
Comment: both solutions work on Ubuntu 16.04 Note: `pcspkr` and `bell.ogg` are independent approaches. `beep` tries to beep using various approaches e.g., [`ioctl(console_fd, KIOCSOUND, period)`](https://github.com/johnath/beep/blob/0d790fa45777896749a885c3b93b2c1476d59f20/beep.c#L100-L121) use `pcspkr` (the sound is coming from PC speaker on the motherboard) while `printf '\a'` -based method may work without it using only `bell.ogg` (the sound is from ordinary speakers). The second method might not work [until pulseaudio service is started and/or `xset b on` is run](http://askubuntu.com/q/836251/3712)
Comment: To automatically enable a pc speaker beep on boot you have to actually **comment** said line in _/etc/modprobe.d/blacklist.conf_ not uncomment it (you want to disable blacklisting, not the other way around).
Comment: The `pactl upload-sample ...` was golden for me. What's the way to permanently configure the sample loading again?
Comment: @ulidtko: Just add those lines lines in your `~/.profile`, or system-wide at `/etc/profile`
Comment: @MestreLion wrong. `load-sample bell.ogg /usr/share/sounds/ubuntu/stereo/bell.ogg` in `/etc/pulseaudio/default.pa`.
Answer: I've encountered this problem before. From what I remember, the problem is that the terminal bell tries to ring an internal computer speaker (as in an old-school desktop) but laptops and some newer computers are missing such a thing.
The only solution I found at the time was to
sudo apt-get install sox

and
play -n synth <duration in seconds> sine <freq in Hz> vol <volume (0-1)>

e.g.
 play -n synth 0.1 sine 880 vol 0.5

Comment: You can also have a nice guitar pluck tone: `play -q -n synth 2 pluck C5`. C5 is the note.
Comment: try my solution - I'd love to know if it works for you!
Comment: you may use speaker-test for this too
Answer: To fix this problem persistently:

Run gconf-editor and if the desktop | gnome | peripherals | keyboard | bell_mode setting is present then change it from off to on
Run dconf-editor and if the org | gnome | settings-daemon | peripherals | keyboard | bell-mode setting is present then change it from off to on
Add pactl upload-sample /usr/share/sounds/gnome/default/alerts/glass.ogg bell.ogg to the file ~/.xprofile (you need gnome-control-center-data for glass.ogg)
Add [ "$DISPLAY" ] && xset b 100 to the file ~/.bashrc

The simplest way to activate this solution is to reboot.
Further, to implement this solution immediately for a terminal window that is already open, run the pactl command and run the xset command in the terminal window in question.
Comment: @Hibou57: Make sure you have the package containing `glass.ogg` installed
Comment: I put the `pactl upload-sample` command in a shell script, but your method is more organized. Thanks!
Comment: If you put the `pactl` command in `~/.xprofile` it gets executed at the start of the GUI session.
Comment: The `dconf-editor` version of the `bell-mode` setting seems to be `org.gnome.settings-daemon.peripherals.keyboard`.
Comment: @lgarzo: Thanks for the tip. I will update the answer.
Comment: Does not work with Ubuntu 12.04
Answer: "Beep can only work if your PC has a traditional old style "speaker", and probably most if not all laptops and small devices don't have one.
However what they often have instead is a sound chip and one or more speaker(s) that can be used to make any sound you want.
So the outdated advise to install the beep command and/or the kernel module pcspkr will silently never work when you don't have the old style speaker hardware.
INSTEAD:  Try playing a sound like this when you want a beep:
paplay /usr/share/sounds/sound-icons/capital

Note this uses the paplay (Pulse Audio Play) command which mixes better with other user level (user app) sounds on your system, and not the older aplay (ALSA Play) command which generally can only play one sound at the same time.  But note however, that PulseAudio calls ALSA to actually play the sound.
My previous suggestion to use play might still work, but running SoX of which play is from, is overkill.

Works for me when all else failed.  Thanks to: tredegar & hk_centos and others.
Answer: I finally found a solution, which doesn't require alsamixer to have a PC Beep option. I think I remember all my changes:
uncomment the following in /etc/pulse/default.pa:
load-sample-lazy x11-bell /usr/share/sounds/ubuntu/stereo/bell.ogg
load-module module-x11-bell sample=bell-windowing-system

per this bug, run pactl upload-sample /usr/share/sounds/ubuntu/stereo/bell.ogg bell.ogg
Comment: Tried this, pactl gave me `Connection failure: Connection refused
pa_context_connect() failed: Connection refused`.
Comment: Maybe [this thread](https://bbs.archlinux.org/viewtopic.php?id=119100) will help - if you've ever run pulseaudio as root.
Comment: I'm having a different problem, actually. Pulseaudio throws `Failed to open module "module-esound-protocol-unix": file not found`. Probably not worth discussing here since I'm running 13.04, though I would love to be able to verify your solution.
Comment: Nice, just slightly different lines for 15.04.
Answer: It might be to late BUT, for the guy in the future looking for this:
printf '\x07'

Answer: As far as I can tell, this is a bug: System beep broken in Karmic despite heroic efforts to fix it.
Comment: "Not enabled by default" does not mean broken, and no "heroic effort" is needed: just `modprobe pcsprk` (in console) or `pactl upload-sample ...` in X11 and the annoying beep is back :)
Answer: If you have actual speakers connected to the computer and you're not getting a beep it's likely because you are using compiz. Compiz is relying on pulseaudio catching the beeps and playing them while metacity bypasses the usual setup and uses libcanberra to play a beep sound. If it works with metacity and not compiz that is your problem, otherwise the answer htorque gave is corrent.
Answer: An alternative approach - set your xterm / console to "Visual Bell" so that when it would beep, the window simply inverts its colours for a short time.
I have a bash function called beep to get my attention once a command is finished.
beep ()  { while true; do  echo -en '\a'; sleep 1; done }

And it is used this way
longrun-command ; beep

Answer: I added this little function to my .bashrc as a replacement for beep:
beep () {
    if [ "$1" = --list ]
    then
        find /usr/share/sounds -type f -exec basename {} \; | sort -n | tr '\n' ' '; echo
    else
        paplay $(find /usr/share/sounds -type f -iname "${1:-bell}*" | head -1)
    fi
}

It searches for a file in /usr/share/sounds starting with supplied argument or "bell" and plays it. beep --list returns list of files in /usr/share/sounds.
# Examples
beep
beep bark
beep trump

Answer: paplay /usr/share/sounds/purple/alert.wav

Answer: Today, June 2020, in Ubuntu 18.04, the whole sudo modprobe pcspkr and commenting out of the blacklist pcspkr part of the /etc/modprobe.d/blacklist.conf file, as described here, doesn't seem to be necessary.
Mine is still blacklisted, yet my bell character sound works just fine!
$cat /etc/modprobe.d/blacklist.conf
.
.
.
# ugly and loud noise, getting on everyone's nerves; this should be done by a
# nice pulseaudio bing (Ubuntu: #77010)
blacklist pcspkr

Instead, just make sure the Terminal bell sound is turned ON in your gnome-terminal settings:
Right-click on the screen in gnome-terminal --> Preferences --> check the box for "Terminal bell" under the "Sound" section, as shown below:

Now run this, and hear the dull "thud" sound of the bell character sound:
echo -e "\a"

This also works over remote ssh sessions, which is super handy when building on a remote machine, for instance, so that it will play the bell sound when the build is done, to alert you:
time bazel build //...; echo -e "\a"

Also note that pressing Backspace when there's nothing to delete will also play this sound in gnome-terminal.
Related:

`terminator` terminal won't play bell sound
Update: Also see @jvriesem's response to my question in the comments under this question here: How do I enable the terminal bell?. I seem to be answering a slightly different question.
Answer: Some motherboards don't have a beep speaker. To get around this, I created a Python script that instead uses FFmpeg's aevalsrc filter to generate beep noises.
Note: you will need to install FFmpeg using sudo apt install ffmpeg
#!/usr/bin/env python3
# This program runs FFPlay to generate beeps.

from argparse import ArgumentParser, ArgumentError, Action
import re
import subprocess

# Custom action for note
class NoteToFrequencyAction(Action):
    _note = re.compile(r"([A-G])(bb|[bx#])?(\d+)")
    _note_factors = {
        "C": lambda x: x / (2 ** (9/12)),
        "D": lambda x: x / (2 ** (7/12)),
        "E": lambda x: x / (2 ** (5/12)),
        "F": lambda x: x / (2 ** (4/12)),
        "G": lambda x: x / (2 ** (2/12)),
        "A": lambda x: x,
        "B": lambda x: x * (2 ** (2/12)),
    }
    _accidental_factors = {
        "x" : lambda x: x * (2 ** (2/12)),
        "#" : lambda x: x * (2 ** (1/12)),
        None: lambda x: x,
        "b" : lambda x: x / (2 ** (1/12)),
        "bb": lambda x: x / (2 ** (2/12))
    }
    def __call__(self, parser, namespace, values, option_string) -> None:
        if not (isinstance(values, str)):
            raise ArgumentError("Should not have multiple values")

        parse = self._note.fullmatch(values);
        parts = parse.groups()

        freq = 440.0
        freq *= 2 ** (int(parts[2]) - 4)
        freq = self._note_factors[parts[0]](freq)
        freq = self._accidental_factors[parts[1]](freq)

        if not type(namespace.__dict__[self.dest]) == list:
            namespace.__dict__[self.dest] = []
        namespace.__dict__[self.dest].append(freq)

parser = ArgumentParser()

freq_group = parser.add_mutually_exclusive_group(required=True)
freq_group.add_argument("-f", "--frequency", type=float, action="append", dest="freqs",
    help="Can be specified more than once, specifies frequencies in Hz of the beeped notes"
)
freq_group.add_argument("-n", "--note", action=NoteToFrequencyAction, dest="freqs",
    help="Can be specified more than once, specifies notes (e.g. A4). You can use b, #, x, bb for accidentals."
)

parser.add_argument("-d", "--duration", type=float, default=1, dest="time",
    help="The duration of the beep in seconds."
)
parser.add_argument("-v", "--volume", type=float, default=0.5,
    help="The volume of the beep, defaults to 0.5"
)

args = parser.parse_args()
del parser, freq_group

aevalsrc_waves = [f"sgn(sin({repr(f)}*2*PI*t))" for f in args.freqs]
aevalsrc_expr = "+".join(aevalsrc_waves)
ffplay_filter = f"aevalsrc=({aevalsrc_expr})/{len(args.freqs)}*{args.volume}:d={args.time}"
print("aevalsrc filter:")
print(ffplay_filter)

subprocess.run([
    "ffplay", "-f", "lavfi", "-i", ffplay_filter, "-autoexit", "-nodisp"
], stderr=subprocess.DEVNULL)

Simply paste into ~/bin/beep and chmod +x beep to make it available. It doesn't quite support the same options, but doing that would make this code a lot longer than it already is.
Answer: This answer works for me using Ubuntu Server with Cinnamon desktop environment installed.  The terminal bell was not working by default.
My solution is similar to the answer by @jdthood: I was able to fix it by toggling /org/gnome/desktop/wm/preferences/audible-bell to true using dconf-editor.
Answer: Some users experiencing the issue in question will only need to open up the Settings GUI, navigate to 'Sound', and under 'Volume Level' increase 'System Sounds' to a nonzero value ( and double-check that 'System Volume' is also nonzero ).
If anyone wants me to add a screenshot, let me know.

Beep in shell script not working?


Why is economic growth measured exponentially rather than linearly?

Question: If economic growth is indeed highly desirable (see this question), why must this growth be exponential? With finite resources, exponential growth might hit limits rapidly (or be impossible?). Why not express growth in linear rather than exponential terms?
Comment: -1: This question is too broad. It mixes *optimal growth*, *possibility of infinite growth* and *how to express growth mathematically* all together in one question.
Answer: Growth as is meant here "must" be nothing in particular. It is a specific metric, the percentage change in yearly GNP/GDP, and it is what it is.
In Blanchard and Fischer 's "Lectures on Macroeconomics", in the introductory chapter 1, page 2, Figure 1.1, the logarithm of USA GNP 1874-1986 is graphed: and it is impressively linear , bar a disturbance around World-War II (a dive before it that was roughly equally compensated immediately after). But this means that
$$\ln Y \approx at \Rightarrow Y \approx e^{at}$$
(for the US Economy, $a \approx 0.030\;\; \text{to} \;\;0.037$ for the period).
It is the data that told us that "growth was exponential" during this period.
(Note that "exponential growth" usually includes the concept of constant growth rate, while  in informal language, "exponential" may also refer to exploding paths, paths with increasing growth rate).
And so economic models were deemed relevant if they could replicate to a respectable degree the observed data.
The question "can this go on forever?" is an altogether different issue, starting with the meaning of the word "forever".
Answer: Because linear functions don't match the data.
You can't express a series
$$[1,2,4,9,16]$$
as
$$f(x)=x+y$$
for any possible $y$.
Answer: Because we use today's capital stock to produce tomorrow's output, some fraction of which is invested, so you should expect something like $dK/dt=\alpha f(K)$ where $f$ is increasing in $K$.
Answer:
growth makes most sense as a percentage. looking at absolute numbers does have value but percentage growth allows for some pretty good comparisons.
You seem to think exponential growth means infinite growth. It is a pretty logical assumption to make, but I believe it takes these models and uses them in a way they were not meant to be used. Economists seldom care about making predictions 200 years in the future. Exponential growth is quite bad at forecasting that far ahead in anything, in shorter time scales it isn't too bad (Source needed).

I'll try and make it clearer:
Consider a basic model of GDP growth. Suppose GDP is growing at 1% per year ($r=1.01$) and initially is at \$1,000,000.  Let $Y_t$ denote the populations size $t$ years after the initial population of $Y_0 = \$1,000,000$. If one asks what the GDP will be in 50 years there are two options.
At 1% per year growth, the dynamic equation would
be
\begin{gather*}
Y_{t+1} - P_t    = 0.01 \, Y_t
\end{gather*}
and the corresponding iteration
equation is
\begin{gather*}
Y_{t+1} = 1.01 \, Y_t
\end{gather*}
Starting with the initial condition, $Y_0 = 1,000,000$, we could calculate $P_1 = 1.01 \times 1,000,000 = 1,010,000$,
$P_2 = 1.01 \times 1,010,000 = 1,020,100$ and so on for 50 iterations.
This is equivalent to:
\begin{gather*}
Y_t = 1.01^t \left( 1,000,000 \right)
\end{gather*}
so that we immediately have a formula for the population after 50 years:
\begin{gather*}
Y_{50} = 1.01^{50} \left( 1,000,000 \right) = 1,644,631.
\end{gather*}

A point I am trying to make here is that exponential growth is really just the size of something as a function of itself in a different state or time frame. If you want exponential growth over a longer timeframe, it makes sense to extend the model.
What if $r$ was endogenous to the model? As Y gets larger, r gets smaller. Still growing exponentially, and the size of the economy in $t+1$ is still dependent on the size of the economy in $t$.
Comment: i feel this answer contains a lot of the intuition needed but is quite messy. I'll try and fix it up. Also, add a few sources. My main point is, exponential growth is a good way to view an economy in the short run, longer run models do not necessarily require this.


Left US after 2 year secondment 4 years ago. Cashed 401K in 2012

Question: Left US after 2 year secondment 4 years ago. Cashed 401K and paid US tax in 2012. I have no experience of the US tax system and am being told I will need to submit a form 1040NR. The terms on the form and incomprehensible to me. Is there an easy way to do this?
Answer: If the terms are incomprehensible, then no, there's no easy way. You have to pay someone to help you (or if you're lucky enough to have a US tax professional in your circle of friends - get some free help).
You probably paid 20% tax withholding on your withdrawal. You're likely to need to pay more.
You can (and should) ask your employer to support you on this, if you were sent to the US by them, and also see if the tax treaty between your country (UK?) and the US provides you benefits, which it might.


Which is a better way to store your photos? RAW or TIFF?

Question: I have read posts that alot of photographers are using RAW to store photos. But the problem I am having is that how do you people view the photos easily when you need them? In the beginning I have stored my photos in RAW but I realised its a pain when Windows doesn't shows any thumbnails and also cannot be used to open using Windows Photos Viewer. I have to use Photoshop to open and view it in RAW format. Is it okay to store it in TIFF format?
Answer: Storing images as TIFF files is very space inefficient compared with raw, as TIFF images store three colours per pixel (at 8 or 16 bits per colour component, 24 or 48 total) compared to raw which just has the monochrome sensor data at 12 or 14 bits per pixel total. This monochrome data is interpolated into colour by exploiting the RGB colour filters placed in an alternating pattern over each pixel. To store the full range of colours available in the Raw you would need a 48bpp TIFF, which would take up about three times as much space (before compression).
Also raw preserves the maximum amount of editing flexibility - you're not commiting to any particular white balance or noise reduction setting. TIFFs are better than lossy JPEG images for archival purposes, but still not as good as raw.
I always keep the original Raw files, and keep a matching set of high quality JPEGs for easy viewing. There are arguments for using TIFF for archival purposes as it's an older, better documented format, understood by a much wider range of software. However if you're concerned about future compatibility then you can losslessly convert your proprietary Raw format images to Adobe Digital Negative files, which is an open format more likely to be supported in the future. The redundancy in an uncompressed 48bpp TIFF will make it slightly more tolerant of data errors, however. As Reid states there are better ways to guard against data loss, such as a backup system with error correcting codes, mirrored RAIDs etc.
Comment: TIFF isn't by any means a simple format; it's actually insanely complex with lots of options and variations. If you want a simple, well-supported non-lossy format, choose PNG. Regarding data errors, if you're worried about that, leaving things uncompressed is a poor way to address it; what you want is computed redundancy (e.g., PAR2) for the whole archive, since data-loss errors are going to take out many disk blocks at once (i.e., most of a file at least), not a few bytes here and there.
Comment: I'm very happy that my camera supports DNG natively, sames some time... In any case, disk is cheap, so I too keep the raw data. That choice is much more flexible. If you're on Windows Vista or 7, there are image libraries that will display the DNG in Windows Explorer and picture viewer (for 32 and 64 bit Windows), so I don't usually keep a lot of the JPEGs around.
Comment: Also, keep in mind that you could lose some metadata when converting from proprietary RAW to DNG.
Comment: Fair enough. I meant it's a straight up bitmap format (if you don't use compression), unlike something like JPEG, which if you opened up would be very difficult to make any sense out of without documentation.
Answer: TIFF is an image format, RAW is a data format. For longevity and to fight obsolescence, between the two, TIFF is the only sensible one.
There are better formats though from an efficiency point-of-view that also are lossless, which I assume is what you were concerned about. PNG comes to mind as one of the best choices (as Reid suggested).
OpenEXR is another open-format with high bit-depth support. JPEG-2000 would have been a contender buy high licensing costs gave it adoption problems.
Comment: @Itai - Your point is EXACTLY the point that I was making. Yes, RAW data has to be interpreted to create an image. It can be interpreted to JPG / BMP / TIFF or other. BUT the RAW data is **THE** data - the actual pure most available information there is of what the camera 'saw' Anything else is 2nd best or worse. TIFF may be useful and powerful, but it's like a skilled copy of the Mona Lisa - it's NOT the real thing. Abandoning RAW for TIFF is putting convenience ahead of excellence - a choice each my make if desired. The argument about losing the software is irrelevant to the main point.
Comment: I don't think the future-proofing argument holds for TIFF vs. raw - since the TIFF format is so complicated, it's easy to have a "TIFF" even now that can't be opened by some programs. On the other hand, all the major raw formats are supported by open-source software which isn't going away.
Comment: Why the downvote? some good info there. I would like to add though that TIFF is an acronym, Raw is a proper noun ;)
Comment: I disagree with the data/image comparison. TIFF is an interpretation of data and information is lost. Any loss of information produces an inferior maximum possible result. A TIFF image can only ever **approach** the information in a RAW master. RAW is the mother-lode. TIFF is a crafted product which may be more convenient than RAW in many situations, but it can never be "better".
Comment: I have to agree with Russell here. TIFF is a broadly compatible and well understood format, but I would not **replace** my original RAW images in storage with TIFF images. That would be like replacing your original film negatives with contact prints...you are LOSING SO MUCH if you do that. RAW files may be specific to each brand, however they are all that less understood than the TIFF format, and support for most is quite ubiquitous. On top of that, decoding information about each RAW format is unlikely to be lost any more than the same info about TIFF...so from a longevity standpoint...
Comment: @RussellMcMahon The reason you are wrong is that you are missed the point that RAW data have to be interpreted. TIFF has a standard and the interpretation of the data is defined the the standard. There is no RAW standard and the interpretation of the data is in the proprietary vaults of the camera maker, some of whom will no longer be around in 20 years or wont care about old RAW files. DNG has an open specification for the format but its interpretation is NOT COMPLETELY defined by the standard and therefore suffers from the same problem.
Comment: I think the availability of decent open source decoders makes the issue of data accessibility less troubling, but since that's done by reverse engineering it's still a reasonable concern.
Comment: ...it is roughly a draw. If you want to *store* **copies** of your images, TIFF is a good high precision format. However the only way to truly *store* your **photos** is with the original RAW. Only then could you maintain complete post-processing latitude and the ability to regenerate new images at any size, or reprocess your photos with new and improved tools with better algorithms to achieve better final output results in the future. Storing digital photos is about more than bit depth...it is about data originality and accuracy.
Comment: TIFF is a container format not a content format.  It doesn't guarantee quality.  After all Group 3 FAX is stored using TIFF.  It's a dog's dinner and the sooner it dies the better life will be for us all.
Answer: It's now 18 months since the question was asked ... :-)

In the beginning I have stored my photos in RAW but I realised its a pain ...
    Is it okay to store it in TIFF format?

No! Not if you do not want to lose "data".
 If data loss is not important to you then any format that meets your needs and standards can be used.
TIFF is an interpretation of data and information is usually lost on conversion from RAW. ie given a RAW file you can always regenerate a TIFF file if you know the decisions and assumptions made. But given a TIFF file it will usually be impossible to reconstitute the master RAW files regardless of what you know about settings etc. Whether this loss of data is acceptable is up to you.
Any loss of information produces an inferior maximum possible result.
A TIFF image can only ever approach the information in a RAW master.
RAW is the 'mother-lode'.
 TIFF is a crafted product which may be more convenient than RAW in many situations, but it can never be "better".
It has been claimed that RAW files may not be able to be processed in future.
 There is no reason for conversion abilities to be lost in future for any data format which is even slightly mainstream and which is formally defined. Whereas hardware to read an 8" / 5.25" / 3.5" floppy diskette or a daa pack or a reel-to-reel tape or a cassette tape or ...  may get increasingly hard to obtain with the passage of time, if the data is of value then retaining a means of manipulating it is easy and essentially zero cost. It may get slightly harder for information long archived but there are too many photographers in the world for such capability to ever now get lost.
And yes, I am well aware of the hubris involved in such a claim and of the shortcomings of human nature. But, it's still essentially true.

ADDED:
This answer has been down-voted - presumably by somebody who places convenience ahead of quality - a valid choice in some cases.
@Itai said:

... RAW data have to be interpreted. TIFF has a standard and the interpretation of the data is defined the the standard. There is no RAW standard and the interpretation of the data is in the proprietary vaults of the camera maker, some of whom will no longer be around in 20 years or wont care about old RAW files. DNG has an open specification for the format but its interpretation is NOT COMPLETELY defined by the standard and therefore suffers from the same problem

Yes, RAW data has to be interpreted to create an image.
 It can be interpreted to JPG or to BMP or to TIFF or some other convenient format.
  BUT the RAW data is THE data - the actual pure most available information there is of what the camera 'saw' Anything else is 2nd best or worse. TIFF may be useful and powerful, but it's like a skilled copy of the Mona Lisa - it's NOT the real thing. A TIFF files includes the user's interpretation after the photographic event of how they want the scene to appear. As an expression of artistry it can be an entirely valid decision to keep the TIFF and discard the RAW file. But you are also discarding data which the camera provided. Whether you are happy with this is up to you.
Abandoning RAW for TIFF is putting convenience ahead of excellence - a choice each my make if desired.
The argument about losing the software is irrelevant to the main point.
 It's an important one but should in no way affect the understanding of the fundamental difference between RAW and TIFF.
 Worrying about converter unavailability is similar to worrying that the rolling code remote control for your older BMW may fail and not be replaceable in 10 years time - except that the car system relies on hardware and the RAW converter relies ONLY on software. If you can backup and retain your images for 5 / 10/ 20 / 30 years (or 100) it is every bit as easy to retain the software. And if there are 100,000+ users of any given RAW standards worldwide, the chances of the converter being unavailable and unrunnable in say 25 years time is less than the chance of the sky falling on Chicken Little. Operating systems change - an where it matters to people, emulators keep them alive.
Comment: @mattdm - We agree :-) As I said "As an expression of artistry it can be an entirely valid decision to keep the TIFF and discard the RAW file. But you are also discarding data which the camera provided. Whether you are happy with this is up to you." My key point is that you can regenerate a semi-infinite number of TIFFs if you know the decisions made to create them, but you often cannot get back to the RAW image from its derivatives. I agree with your Ansel Adams negative/RAW  & Print/TIFF analogy. Offered an Ansel Adams negative and a print from it by a top print maker, I know which I'd take!
Comment: I hear your point on the "real thing", but I think it's not quite right. The real thing of a photograph comes from the photographer, not raw data from the sensor, and an unprocessed RAW isn't that. Consider the difference in value of an original print by Ansel Adams vs. a print from the same negative by a different printmaker. The RAW is like the negative — it isn't the photograph. It's not a finished work like the Mona Lisa. A TIFF can be — it's a final, "developed" image. It's not like your example of a copy of the Mona Lisa at all.
Answer: There are very good reasons to save the raw and equally good reasons to save it as a TIFF - even without considering the preview. (this answer assumes you want to keep the images for the long term, if you only care about the next few months you can ignore it)

Raw is the original, it is the only original, converting to TIFF loses data and editing options - so you should save the RAW
Raw is camera specific, and with the speed of technology progress it's entirely possible that in ten years you wouldn't be able to find a program that can process today's raw - so you should save the TIFF
DNG is an interesting compromise because its a non camera specific raw format - but 1. it's not widely adopted yet (compare to TIFF, JPEG, PNG or even Canon's CR2 nad Nikon's NEX it's virtually unused), it's entirely possible that the format will be abandoned (and having your data in a standard file when no one is writing software to read it is just as problematic as a proprietary file that no one can read) it's also possible that as the file format evolves with technology software will stop supporting the old "obsolete" parts of the spec - again resulting in a file you can't use - so DNG has the same drawbacks as saving the original raw.

So, my recommendation is save both the RAW and the TIFF.
Answer: Interesting discussion, one that has led me to some conclusions of my own. To comment on one of the above answers: "Consider the difference in value of an original print by Ansel Adams vs. a print from the same negative by a different printmaker." I think the art world would value that specific print; but if the negative were somehow destroyed, that would have been a terrible loss to the late Ansel Adams since he could always make another print.
So who's viewpoint are we taking here? The gallery owner? Or the photographer? And consider that, although a print might be the final masterpiece, the photographer might want to come back to that negative and print it a whole new way, from a new matured sensibility -- or maybe "just because." To the photographer, the raw material, the negative, has considerable value, possibly more PRACTICAL value than the print because the print (the "interpretation") can always be re-rendered. And don't forget that many of the great photographers had their negatives printed by others, so we can't always assume that "a different printmaker" lessens the value, or the importance, of the negative.
So -- again assuming that we will be able to read at least the popular RAW file formats long into the future -- I have to privilege the digital negative over some current interpretation that is represented by a TIFF. One negative, multiple TIFFs. One TIFF, and that's all she wrote, the image is frozen in time to a given interpretation (and yes, you can continue to further interpret and alter that TIFF, but then you are working from a copy and not the original). I'm storing my stuff as RAW, PLUS any "interpretations" (TIFF, JPG, etc.) I make over time. Storage is cheap. But if I had to choose, it would be RAW.
Answer: Storing your photos in RAW/DNG format preserves your ability to convert or 'develop' your RAW images in different or improved ways in the future.
This is the biggest single advantage of saving your images in RAW/DNG format.
Examples of this are
- you can use a different or improved demosaicing algorithm
- you can change the noise reduction
- you can change the colour and exposure conversion profile
- you can change the white balance
- you can change the white point, black point and conversion profile
The optimum place to apply these changes is to the original RAW data where there has been no information change or loss.
While RAW formats are proprietary, and this would seem to limit their usefulness in the future, you are in fact fully protected by the Open Source nature of the alternative conversion libraries provided by Dave Coffin (dcraw). I use the words RAW and DNG interchangeably here since many cameras will store in either DNG or RAW format.
Comment: is there any way you can view it from Thumbnails in Windows Explorer without opening a software?
Comment: I use Ubuntu Linux so can't reply to that question. But Picasa (in Windows and Linux) does a fine job of of viewing and organising RAW/DNG photos.
Comment: @Digital Dude: BBischof's already told you how to "view it from Thumbnails in Windows Explorer without opening a software" - there are a number of available packages that, when installed, will display thumbnails for raw files in Windows Explorer.  Whether you are prepared to pay a small fee for that functionality is a different matter.
Comment: Beware of viewing RAW thumbnails. RAW files are not images, they have to be transformed. When you 'see' a RAW file as a thumbnail or preview (i.e. before developing it), you see something which may not look as expected and often looks dull and different from the image you expect to see. 'Why do my RAw images look so aweful' IS one of the most frequent questions people ask about RAW files! DNG is the same in this regards.
Comment: @Itai: many cameras now store thumbnails/previews in the RAW image file. These thumbnails are what you would see if you had saved as a jpeg instead of RAW.
Comment: @labnut - Yes but they depend in image parameters being set, including WB for example. Many people choose RAW to avoid having to set those ahead of time and so they still get incorrect thumbnails.
Comment: @Itai: saving your raws as DNG allows you to update the embedded thumbnail at any stage (for example in Lightroom) to match the currently defined raw parameters.
Comment: DNG is not a raw format.  It is interpreted.  There are cameras which output it as their raw format, but it's not the sensor data.
Answer: I am not a professional photographer, I photograph what I like.  I archive raw and its sidecar file to DVD disk.  I store an artistically created via exposure and composition adjustments etc. from the raw file to a TIF format and store to two separate hard disk drives.  I store a copy of a TIF to JPG conversion for searching and selection processes.  I copy the TIF format for the desired end result by searching for the desired photograph from the JPG format and then go to the TIF file.  The raw files are typically 25Mb, the TIF files are typically 70Mb and the JPG files are typically 250k.  The JPG is fast for searching, the TIF is as I desired and the raw file is available to change to a different outcome.  File space is cheap and I probably won't live long enough to exceed my availability to any of the files.


Can I selectively hide calendar items from the Live tile?

Question: I have some recurring calendar reminders set up that I really have no need or desire to see on the Start screen. Is there any way to selectively hide these from the Live tile, while still having them viewable within the app itself?
Answer: No. At the moment its not possible to select what to show or not to show, of upcoming meetings on the live tile. You can however, choose to turn it off.
On the live tile you can make a small tile so it wont show upcoming meetings, or you can go to settings, scroll all the way down and choose: Show on calender.
To hide from lockscreen go settings -> lockscreen -> and then choose what to show, or not show.


How long must an employer hold a paycheck?

Question: I am unable to pick up my final paycheck from my employer immediately.  How long do I have under federal law to retrieve my paycheck before my employer is no longer bound to honor it?
Comment: Can they mail it to you? Also, this is likely to be a state-law issue, what state? I know in CA the employer must go to great lengths to get someone their final paycheck.
Comment: I am in Alabama.  Since my question is about federal law, then if there is no such federal law, I would be satisfied with "there is no such law" as an answer.  I'm not sure what kind of evidence one might provide to back up such a claim, though...
Comment: I went and got my paycheck.  However, I did receive an email that said, in essence "Come get your check **now**, or don't bother coming to get it at all."  That made me curious about the situation in a purely academic sense.
Answer: I found several articles meant to inform business of their obligations in dealing with unclaimed paychecks:

https://www.thebalancesmb.com/how-do-i-return-unclaimed-paychecks-to-the-state-397927
https://smallbusiness.chron.com/employee-rights-uncashed-paycheck-12403.html
https://community.intuit.com/articles/1768963-understanding-escheat-regulations-for-unclaimed-wages

They all focus on state law, and I saw no mention of any relevant federal laws.  Therefore, in answer to your specific question, I would conclude that there are no federal laws governing this situation.
As far as state law, the articles agree that all the states have laws under which the employer will be required to hold the paycheck for some period of time (on the order of a year or two), and perhaps to attempt to notify the employee by certain specified means.  The details will vary between states.  After that time, as mentioned in Andy's answer, they are required to turn it over to the state's unclaimed property office, who will hold it in the employee's name, indefinitely.  The office will typically have a publicly searchable database showing all the funds they hold.  The employee (or their estate or heirs) may then contact the state at any time in the future and collect the funds, with no time limit.
There is no circumstance in which state law would permit the employer to take the money back.  That would constitute wage theft and could be a crime.
So even if it takes you fifty years to get around to collecting your pay, you'll still be able to get it - you just may have to get it from the state instead of from the employer.
Answer: I don't know how long they are required to hold it, but i think that's largely irrelevant.  If you already did the work, they are obligated to pay you. If you never get the check, they would probably mail it. In some states, if you don't cash it within a certain timeframe they must forward the money to the states unclaimed property department, where you would be able to claim it.


how to motivate student that programming will give bright future to them?

Question: some students in my class are leaving CS because programming is difficult and think that it will not give them bright future. how to motivate that students, that their interest is develop in programming and they become satisfied for their future.
Answer: This might be a mistake, actually. Everyone is different. People like doing different things. Programming isn't for everyone, nor is the wider world of Computer Science as a whole. My daughter, for example, is perfectly happy as a Philosopher. My son is perfectly happy outside academia.
Convincing someone to do something (a kind of advertising) may do them harm in the long run. People spend millions of dollars convincing people to consume sugary drinks, to their detriment.
If you make the classes interesting, with interesting problems to solve, those who want to do it will stay. Wish the others well and focus on those who want to work at it. Some of us have found that group work (pair programming) is a motivator, introducing a social aspect to learning as well. On the other hand, it is possible to make learning programming as dull and demotivating as learning multiplication tables.
I'll note that many things are hard. Becoming an olympic athlete is hard. Some people are willing to put in the work to do it. For others, it isn't worth that effort.
Saying the "future is bright" is something you can't honestly predict. Many things could happen that make it less bright. The need for people specializing in CS might decline in future years as some processes become more regularized. This has been the history of the world, actually. One takes a chance on the future no matter what you do, so you might as well follow your own dreams, not those of someone else.
Answer: I used to teach adults (most well after college age) programming so they could get jobs after a disability caused them to leave their previous job. They were highly motivated to learn enough in one year to get hired.
What I focussed on was to make their learning free of unnecessary difficulty by pointing out the usual problem areas and trying to make my explanations direct, clear, memorable and interesting.
Your excitement about programming will interest them. Some will drop out, but that is not your issue. For any problems you cannot directly solve in your classroom, get help from the administration, and just focus entirely on your part, which is to teach and assist.
Be sure to explain that at times programming IS difficult and frustrating, and sometimes we have to choose a different way of solving a problem. Usually later it can be changed when a better solution is seen.
That's the best advice I have for you. Good luck!
Answer: Do you maintain contact with your former students?  I have a sizeable number of former students earning nice livings at places such as Apple, Microsoft, Google, Facebook, and YouTube. Others are in great graduate programs.  Some are academics at places such as Stanford, UMiami, and UMaryland.
They are doing very well.  I use my network to benefit my current and former students.  It's quite powerful.  And it serves as a beacon to my present students.


Hartree product and the Slater determinant

Question: I am very new to theoretical chemistry so my question may sound very basic to most. It is known that the Hartree product does not satisfy the antisymmetry principle for electrons while the Slater determinant is able to do so. Thus, the electronic wavefunction is often written as a Slater determinant, rather than a Hartree product. However, I am just wondering if the Hartree product can still be used to approximate the electronic wavefunction or if it is still being use to do so in some theoretical methods? And if the Hartree product is used, what other measures are implemented to ensure that the antisymmetry principle is not violated? Also, in Density Functional Theory, which is used to approximate the wavefunction, the Hartree product or the Slater determinant?
Comment: The Hartree product will always produce a physically unsound wave function guess; it cannot obey the antisymmetry principle. The Slater determinant is the easiest formalism to guarantee it. It is therefore used on most applications.
Comment: @TanYongBoon strictly speaking, you don't need Slater determinants for DFT because it solves for the energy using the density and so you can do orbital free/pure DFT that doesn't use Slater determinants or orbitals at all. In practice, we often formulate DFT using the [Kohn-Sham equations](https://en.m.wikipedia.org/wiki/Kohn%E2%80%93Sham_equations), which computes orbitals/Slater determinants for a fictitious 1 particle potential.
Comment: @Martin-マーチン But are there any cases where it is used instead? Because I was just reading this introductory DFT text, which made no mention of Slater determinants under the DFT section and only talked about Slater determinants under the section on HF... Anyway, is Slater determinant even relevant to DFT since the wavefunction isn' really computed?
Comment: @TanYongBoon basically, the Hartree product can't be used unless it is antisymmetrized and the most intuitive way to do that is to form a Slater determinant from the same set of orbitals.
Comment: @Tyberius If I may enquire further, how is the Hartree product different from the Slater determinant in terms of approximating the wavefunction? Yes, we know that only the latter satisfies antisymmetry principle and that it is also more complicated to compute for large N. But are there any other advantages of using a Slater determinant over Hartree product as an approximation of the wavefunction?
Comment: @TanYongBoon A Slater determinant is essentially a linear combination of a bunch ($N!$) of Hartree products with the electron labels permuted to. By including all of these instead of one individual Hartree product, you account for the fact that exchanging the labels should lead the overall wavefunction to change sign. I would say the functional form of the two is very similar and that the key difference is that Slater dets properly describe the antisymmetry of fermions. This may not seem like much, but this antisymmetry is hugely important to properly describing electron behavior.
Comment: @Tyberius I think that answers my question. Maybe u can expand it into an answer.
Answer: The Hartree product can definitely be used for approximate calculations; as you might know Hartree developed his method for atoms in 1927 (for reference, the Schrödinger equation was discovered in 1926) and he implicitely used a Hartree product for the wave function, although the connection to the exact solution of the many-body Schrödinger equation via the variational principle wasn't know. It was Slater in 1930 (and, independently, Fock) to introduce the determinant form which bears his name. When using the Hartree product one has to account for the Pauli principle "by hand", by allowing only two electrons to occupy the same spatial orbital.
By starting with a Hartree product, enforcing the Pauli principle and applying the variational principle one obtains the Hartree equations, which are similar to the Hartree-Fock ones but are missing the exchange term, usually indicated by $K$; this term is, however, smaller than the  electrostatic term $J$ so Hartree calculations are meaningful and give useful results, although of course very approximate ones.
Kohn-Sham DFT calculations use in principle the Slater product form, but in practice, depending on the exchange-correlation functional used, they lead to equations which may be more similar to the Hartree ones (i.e., without the exchange term) than to the Hartree-Fock ones. In the original LDA (local density approximation) functional the exchange term is dropped and replaced by a functional of the electron density which is much simpler to compute. As a result, DFT-LDA is similar in complexity to the Hartree method, not to the Hartree-Fock (a rather significant simplification). However, most modern functionals for molecules (as opposed to solid state calculations), e.g. B3LYP, re-introduce the exchange term (with a scaling coefficient).
The Hartree form of the wave function can be also used to compute expectation values (e.g., to compute dipole moments); you can check by looking a the Slater-Condon rules  that the results you obtain with Hartree functions are, for one-body operators, the same you'd get using the proper Slater-determinant form.


Glass used in biometric machines

Question: I would like to know what kind of glass is used in biometric attendance machines over which we press our thumb? Is there something special about these glasses or their manufacturing?
Answer: According to this glass manufacturer it is more about the optical properties than mechanical ones. They are looking for:

Homogeneous illumination of the touchsurface
Transparent and durable in UV and IR light radiation
Temperature-resistant to heat development in LEDs

They use borosilicate glass and aluminosilicate glass, which are by themselves scratch-resistant.
Answer: Yes, it is probably the same type of glass used for smartphone screens some version of an aluminium silicate glass that resists scratches, grease, dirt etc for the very same reasons.
They also use oleophobic coatings to avoid sticky fingeprints etc...

Glass used in biometric machines


How to make bitcoins from other cryptocurrencies?

Question: I want to know how can I convert other cryptocurrencies like BlackCoin or LiteCoin to Bitcoin. There are many cryptocurrencies out there and the main difference between most of them and Bitcoin is popularity. At the moment, Bitcoin is way more commonly accepted as a payment option than the other cryptocurrencies, so they aren't really useful or flexible at all... So please tell me and explain how can I do this!
Answer: The only way to convert them is by trading one for the other, or by going through a third currency.
Meaning:

Find a person or exchange platform that trades exactly the currency pair you want e.g. LTC/BTC or BLK/BTC.
Trade LTC -> USD -> BTC

Some exchanges trade a number of different altcoins, so they would lend themselves to do what you want. I have no experience trading anything but Bitcoin, but I've seen that for example HitBTC trades LTC/BTC, and BTER trades BLK/BTC.
I have used neither exchange and therefore cannot recommend them, just giving them as examples.
Comment: I thought about this way but I hoped there would be another one...Anyway,what does "altcoin" mean?
Comment: @VIPaul: [Altcoin](https://en.bitcoin.it/wiki/Altcoin) is the umbrella term for Cryptocurrencies forked from Bitcoin.
Comment: @VIPaul take a look at [shapeshift.io](http://shapeshift.io)
Answer: If you are not in New York or North Korea, you can use ShapeShift. If you are in New York or North Korea, you need to use a VPN to use the site. It doesn't even require you to make an account and you can easily swap between various cyrpto-currencies.
Comment: Interesting to see New York lumped with North Korea.
Answer: there! You can easily user our platform ShapeShift.io, as another responder has mentioned. We support several dozen digital assets for exchange. If you would like to watch our demo video to see how to use our service, please check out our about page: https://info.shapeshift.io/about
We support both Blackcoin and Litecoin, we don't require you to create an account and it can take just a few minutes to process. Really easy, simple process!
Questions? Reach out to our customer support: https://shapeshift.zendesk.com/hc/en-us/requests/new


How to make IK Multimedia Stealth Plug work on Ubuntu?

Question: I used Wine and I have Amplitube set up on my labtop but I can't get the Stealth Plug drivers to work on Ubuntu. What should I do?
Answer: Works for me very well.. in Ubuntu 12.04 just "plug and play" after plug in, in sound settings check "Stealthplug no bass boost" and MUST RESTART Machine.
After that is Stealthplug the main system audio card (ALSA) and work fine with Qjack, Qsynth, Qtractor (this chain of startups is a must...) and the Qsynth hosts Soundfonts (.Sf2 files), that are many good quality and free!
After my first tests also in good audio sync with MIDI (must say that I use Stealthplug only as input and output card without any VST or ASIO advantages - have my own hardware based guitar multieffect gear - KORG AX3000G).
At last but not least, Qtractor is so NICE simple, that I could now after years of seeing "complicated" workspaces of innovatives massive DAWs, really see simple windows, that suggest me those "little displays" of my beloved hardware of the 80's and I can now again put importance on "HOW IT SOUNDS" and No "How it looks like".
Answer: I don't think it could work in a wine environment. You should use linux specific software like Jackd and Ardour. Maybe you should try ubuntu studio distribution that includes both of them, a realtime kernel, and many others audio software.


What is the difference between 氏 and さん?

Question: I learned that 氏 is more respectful, and have seen it used with presidents and prime ministers, but I am not sure if it is still appropriate to use both terms when addressing people verbally.
Answer: Related: What does 氏 mean after a name, how is it different from さん or 様?

The sound of 「氏」 is highly objective, compared to 「さん」.
On the other hand, 「さん」 is still respectful but also often includes somewhat friendly and subjective nuance.
As a result, it is very common to say 「○○さん」 to mean "you", while it is not standard to say 「○○氏」.
In contrast, 「氏」 is preferred  to 「さん」 in news articles, as it should be written in an objective style.

So, the reason you see 「氏」 is used for presidents and prime ministers is that they often appear in such formal and objective writings as news articles.
In our daily conversation we often refer to the prime minister of Japan by 「安倍さん」 rather than 「安倍氏」.
This is because spoken words tend to be more or less subjective.
The difference of the two words are rather their nuance.
There is no restriction to the kind of people to which 「氏」 and 「さん」 can be used.
Answer: As a native English speaker fluent in Japanese, I notice common usage of 「氏」is closer to "gentleman," and 「さん」is closer to "mister."

What is the difference between 氏 and さん？


How can I fix a "Cannot communicate with battery" error on Canon 7D?

Question: If I see the "cannot communicate with battery" error message on a Canon 7D, is there any way to fix it without sending it back to Canon?
Comment: Are you using an OEM battery from Canon or a third party battery?
Comment: Hmmm..good question. This is actually not my question - it's a problem brought to my attention by Twitter (friend of a friend situation). I think your answer gives a lot of useful suggestions, though. Thanks!
Comment: I've been tryng all the possible solutions, but any solve the situation. A couple of days ago I was working in a very wet enviroment, so I guess it is a matter of humidity. I will leave it with all its doors opened and will wait. Anyway, it permits me to use it although has no communication with the battery
Answer: A few things to try:

Try a second battery
Try a second body
Try OEM and third party batteries
Accept the warning message about the lack of communication and try to use the battery anyways
Try pulling the battery out and reseating it at least a few times
Try removing the tiny watch style battery as well as removing the regular battery at the same time. This will reset some if not all things on the camera, so keep that in mind.
Update your firmware to the newest version
Try a battery grip if you have one
Comment: Swapping to another battery, powering up and back down, then putting the first battery back in has worked for me the very few times I have seen this error.
Answer: 7D owners, I hope this fixes your problem, don't waste your time resetting the camera, wiping battery contacts, putting it in the freezer, etc.
I didn't mention in posts on other forums, I've been an instrument technician for more than 40 years and don't have a problem going into the camera and making the repairs, I've done so on other Canon cameras and Canon lenses.  Service manuals don't always give the order of which screws need to be removed.  I wouldn't know in the case of the 7D because I've never seen a service manual.
We have been led to believe that the cause of the problem was due to a screw making the ground connection on one of the circuit boards had come loose and was floating around inside the camera.  The first symptom is that we get the famous error as described on the subject of this thread.  If the problem goes long enough unfixed, not only can we not read the battery level, I've heard that even if the camera is turned off, the battery will discharge over a very short period of time.  Worse than that, if the loose screw
shorts between some traces  on any of the boards, catastrophic results will occur, then circuit boards actuallywill have to be replaced.
I held off repairing my camera, simply because I didn't have the time.
I put out the request on multiple forums asking which screws need to be removed.  As it turns out, a total of eight screws need to be removed to remove the bottom panel of the camera.  Six screws on the bottom and one screw on each side of the camera.  I took my camera apart, found the loose screw, applied a tiny drop of #242 blue loctite and put the screw back where it belonged.  It should have been loctited in the first place, never was, I have heard that Canon is charging people as much as $300 for a repair that never should have been necessary, because of a factory defect.  I took a photo showing the bottom removed, it is obvious as to where the screw is missing from.  The screw was jammed up into the camera, a couple taps on a table top loosened the screw.  There are three types of screws, three of the screws on the bottom have a blue thread lock, probably loctite.  Three of the screws on the bottom do not, they are the same size.  The two screws on the left and right side near the bottom of the camera are a little longer than the bottom screws, don't get them mixed up.
I would attach my photo showing where the screw is missing from but don't know how to attach a photo to this post.  I've seen similar photos elsewhere on the web.
We owe the help to John Clark
Pelagic Visions Marine Imaging
Blue H2O Cozumel Watersports
http://www.padiowsi.wix.com/blueh2ocozumel
USA Direct   813 398 0791
Mexico Cell  987 111 2170
Facebook     Pelagic Visions
John made a 15 minute video, it is on youtube  showing exactly what he had to do to perform the repair.
This video is being shared with John's permission:
https://www.youtube.com/watch?v=DQaejgJM1Rc&list=UU2MDDaPI8sz97ybNJ2mZDyg
Another video is available here: https://www.youtube.com/watch?v=DQaejgJM1Rc
As I mentioned, if you let this problem go too long, it may only get worse, damaging more boards and costing you more money.
And, yes, I did ask others which screws were to be removed, I didn't have the time to experiment, I had other priorities.
Jim, owner of many Canon products
Empirical Technology
Answer: I saw a post that suggested putting the camera body in the freezer for 6 minutes. Tried it, didn't work. Yesterday I thought I would try it again for a little longer. I put the camera body in the freezer at 10 am. At 6 pm. While working the discus event with my secretary, she said "hey you know there is a camera in the freezer?"  Panic.  It was frosty. Removed the battery, let it defrost for over an hour, put in charged battery, it worked, no more battery issue. Bizarre.
Answer: I also has problem with "battery communicate". As some user in internet I doesn't find one screw on bottom of body.

After a while I found it near the motor. He was dragged a magnet and short T-line on the battery housing.

This photos of another user with some problem about screws (he miss 2 screws):

Short circuit by screw!!! SOLVED: Canon 7D "will not communicate with battery"
http://www.dpreview.com/forums/post/54348668
Comment: Can you elaborate a bit more? Is this _likely_ to be the case or just one possible cause?
Comment: OK. This is the most possible cause of error "will not communicate with battery"


Can I change the version of the language in my answer (Python 3 to 2), or do I post a new answer?

Question: I wrote a Python 3 answer. I called it Python 3 in the title; however, it works equally well in Python 2. I discovered that I am able to remove several bytes from the answer, but only if I use Python 2 instead of 3. Is it acceptable to change the answer from Python 3 to Python 2, or should I post a new answer?
Answer: Either one is acceptable
I've personally done both of these things it really is up to you.  An additional option is to have one answer with both the python 2 and 3 versions in it labelled separately with a bit of explanaiton.
If you want help deciding which to do I would recommend doing a new answer if you feel the the golf is substantially different (a rather subjective metric).
Answer: The choice is up to you
I usually change the version personally. I don't program in Python that often, but for Java 8/10/11 it's similar. I usually use the header Java 8 if it doesn't use any var from Java 10, or .repeat from Java 11. If I do end up using those later on in the golfing process, I simply change the version to 10/11 respectively. I could of course just have a header Java, but I usually use the lowest version required for my function/program.
Although I don't program that often in Python, it's similar. Usually Python 2 is shorter in my experience, due to print ...; in Python 2 vs print(...); in Python 3, or because a mixture of spaces and tabs can be used for code-indentation, for which only one of the two is allowed for Python 3. Python is mainly strong in the added builtin that Python 2 lacks (and Python 3.8 is from what I've seen thus far even shorter in most cases). I don't see any problem in changing the language to/from a different Python version in that case.
If they are substantially different you could also add both versions to your answer, and maybe explain why the code is shorter in one Python version in comparison to the other. Something in the lines of this below for example:

Python 2, 321 123 bytes
code here

-X bytes by switching from Python 3 to 2, allowed me to golf A and B. Initial Python 3 answer can be seen below.
TIO-link here.
Explanation:
# explanation here

Old Python 3 answer:
code here

TIO-link here.


Dynamically theming Status Bar according to app's Action Bar?

Question: I have no idea whether this question is on-topic or off-topic here, because it is related to problems with an Xposed Module. Moderators, please tell me if this is off-topic or not.
I'm running on an AOSP-based Jelly Bean 4.2.2 ROM, rooted and having Xposed Framework. I have GravityBox, Tinted Status Bar, XBlast Tools, etc. and many other modules installed on my device, including the Monster UI module, which themes my device framework to make all apps look like having Material design (checkboxes, progress bars, ripple effects, etc).
I have applied a system-wide Material design colour scheme, including dialog boxes and action bars for apps which were using Holo themes, all through Monster UI. On top of that, to get the full Lollipop effect, I have used the Tinted Status Bar module to tint the Status Bar according to the app's Action Bar colour. When I launch any app's main activity, it works fine, and tints the Status Bar accordingly. But, when I switch back and forth across various activities in the app, the Status Bar gets tinted White, and sometimes that makes the Action Bar turn white too, rendering the text/icons which both were supposed to display, invisible.
How do I fix this ?
Note : All modules work perfectly, and none are conflicting with each other. I checked MANY times for any such conflicts, but there were none. Disabling other modules too didn't work out.
Comment: Could this be a combat between two or more theming apps?
Answer: Look's like a bug in Tinted Status Bar module, because other than this everything works fine.
So, give your feedback to module developer MohammadAG - XDA Profile
or Tinted Status Bar thread - XDA


Preserving Layout of Original File

Question: fairly new to Ebooks and publishing in general. I am attempting to publish a poetry collection. Unfortunately, I've been wracking my brain over how to preserve the formatting of my source file (.odt) for the .epub version. None of the built in converters (on amazon/kobo) convert it nicely - either they butcher the pagination, rearrange the lines of my poems, or some combination of both. I found a solution in amazon's textbook creator, but that doesn't work for other sites. The layout and formatting is highly important in poetry, so I'm wondering how to accomplish a fixed layout (or at least maintain some form of pagination/formatting) for the other sites? Thanks in advance for the help.
Answer: First, I've formatted lots of poetry for epubs, so I can offer insights.
I don't know about what kind of visual demands you have for poems. But I'm assuming that you have the usual ones -- keeping lines of a stanza together, having the proper indents and line widths and forcing page break.
Poetry is easier to format by creating HTML and css style sheets.
The html source looks something like this:

 "Look not thou on beauty's charming, –

 Sit thou still when kings are arming,  –

 Taste not when the wine cup glistens,  –

 Speak not when the people listens,  –

 Stop thine ear against the singer,  –

 From the red gold keep thy finger,  –

 Vacant heart and hand, and eye,  –

 Easy live and quiet die."

Admittedly, this is a plain vanilla example. Depending on the formatting, you may want to use two different classes for individual  lines with different styles. Look at this css
p.line-verse {
    text-indent: -2em;
    padding-left: 3em;
    padding-right: 3em;
    line-height: 80%;
}

You get the point. Once you have the css right, it is trivial to create html pages for poems. More examples are here: http://epubsecrets.com/formatting-poetry-in-epub-part-1.php and http://epubsecrets.com/formatting-poetry-in-epub-part-2.php
The two issues you have are: 1)would the advantage of being able to style poetry in html and css outweigh the convenience of using a word processor and 2)are you testing the poetry book adequately on different devices? Poetry can look bad on mobile devices, so you need to make sure they render reasonably well on all devices.
It may simply be easier to pay someone to format an ebook for you and then keep the template for later ebooks. Or you can crack open any epub file of a poetry ebook (.epub is just a zipped file with the file extension renamed).
Or you can unzip any of the Project Gutenberg poetry ebooks (which are formatted pretty well: http://www.gutenberg.org/wiki/Poetry_%28Bookshelf%29 ).
To summarize my answer: It is actually not hard to format poetry for html; it actually can be easier than doing it from a converted word processed file. My feeling is that using word processed documents as your source creates more problem than it solves when you're trying to format something like poetry. Fixed layout books would definitely provide more pixel accuracy, but the ebook's appearance would be unpredictable on smaller devices.
Comment: "Poetry is easier to format by creating HTML and css style sheets. ". I was going to say this. This guy knows what he's talking about. I'm  also an author or EPUB books, and software that creates EPUBs. Most tools do not do well with poetry, hence your need to know HTML and maybe some CSS.

Preserving Layout of Original File


system problem! ubuntu 12.4

Question: when I was upgrading to ubuntu 12.4 I had to leave and accidentally turned off the laptop in half update. When lit it not entered the system, it put the screen in black and looked just the mouse. I had to install ubuntu 12.4 from a dvd drive apart, when I installed told me that was already installed, it saids that if you wanted to install ubuntu 12.4 with ubuntu 12.4 and I did it, but now I have two ubuntu 12.4 and also can not find my files . What I can do?
Answer: To get your files you could try to start Disk Utility and then search the drives and partitions with that tool. You should be able to mount the partitions and open them with Nautilus (file manager) by clicking onto the path shown after "Mount Point":

I don't know if you can rescue your old system with all the custom settings. Possibly you should do a complete reinstall and use the full harddisk after you got your files.

system problem! ubuntu 12.4


Should there be a general policy for putting comments on "not-suitable-for-MO" questions?

Question: Right now, there is a question posted on MO that rightly does not belong to MO: The equivalence of the mathematical induction and the principle of the smallest. Of course, such questions comes and goes every-MO-days. More often than not, if they are lucky, they get one or two polite comments that MO is not right place for asking such questions. What if they also get a comment that also adding that "look at that reference" or "maybe you could find an answer in this (other) site", or even a very short hint as an answer. Indeed, I was about to put such a comment for the question linked above. Then I said to myself, maybe it is wrong doing. Is there any general policy for putting comments on such questions? Or better to ask: Should there be a general policy for putting comments on such questions?
Comment: I think your question is fine, but I don't understand what you mean by your title
Comment: I used to try to explain why a question was unsuitable, it just made the OP angry. I did want to tell some to move to MSE...so i am finding the current setup relaxing, either vote to close or vote to migrate.
Comment: @quid, I see what you mean. It happened a few times too often for my taste. Granted, I am on the thin-skinned end of the spectrum.
Comment: @WillJagy you make it look as if each OP gets angry. This was not at all my experience. First-time askers getting angry were more an exception than the rule, in my experience.
Comment: @YemonChoi Please feel free to change the title. Indeed, I wasn't sure about it as well!
Comment: @YemonChoi I have changed the title. Please let me know if it is OK now.
Comment: The new title looks fine
Answer: My feeling is that one should not give answers (or hints) to questions that are not appropriate for MO, even in the comments.  Doing so encourages people to post inappropriate questions in the hope that they'll get an answer even though the question is closed.
Comment: Documentation? Can you cite an example of someone who was encouraged to post an inappropriate question (I mean, a question the poster knew to be inappropriate) to MO by seeing answers or hints posted as comments to previous inappropriate questions?
Comment: @GerryMyerson in *numerous* discussions about on-topicnes precedence where brought up and sometimes people said they were sure this is alright as the found a similar question on the site via a search. Granted, this is mainly for soft-questions not what is mainly discussed here, but then how would you show or know what precsiely encouraged a passing-by asker to ask there question here. Sure, it is a bit of a guess, and I might agree some people worry too much about it, but your precise requests still strikes me as slightly unfair as even if it happens frequently  might be impossible to show.
Comment: @quid, had Andy presented it as a guess, I'd have had no problem with his post. He presented it as an established fact, and mathematicians don't do that if they don't have a proof.
Comment: @GerryMyerson thank you for the clarification. This a fair point.
Comment: I sometimes wonder, why it is possible to vote on questions that are not appropriate for MO; isn't a vote also a kind of comment?
Answer: I am on the opposite end from Andy. My (humble, as usual) opinion is that (barring complete trivialities where you intend to send the person the direct message that he is either too stupid or too lazy to waste your time on or that his question has absolutely nothing to do with mathematics), you should demonstrate that the problem is easily solvable before casting the first vote to close. So, my current policy is to give out enough information for a reasonably clever reader to finish the solution without too much effort (and even then I sometimes abstain from voting to close myself). I understand what Andy is afraid of, but I am much more reluctant to make the error of the opposite type and drive someone away without a really good reason. The inappropriate questions that hang for a day or two can always be deleted automatically after closure but the reopening of a decent question may easily happen too late, when the OP has already sent us to the Hell after seeing his question downvoted and closed without any comment (or with some meaningless and technically wrong comments, I'm not sure which one is worse) within half an hour after posting.
Comment: "But, I think, essentially we agree anyway. :-)". As usual, again. It is the language barrier that really separates us (plus the choice of the side of the story to present first). I also don't mind the sketch + the suggestion to ask elsewhere NEXT time, or the internet {link/search query} that would lead to the answer in a matter of seconds, say. Those are completely fine. I just mind implicit de facto message "Get out of here!" without readiness to say so openly.
Comment: What about the situation where 'the empty information' is already enough for the "reasonably clever reader to finish the solution without too much effort". (In my opinion, this being so does not make the OP  ncessarily stupid or lazy.)
Comment: {'the empty information' is already enough for the "reasonably clever reader} and {"this being so does not make the OP necessarily stupid or lazy."} are compatible only if the empty information is actually the information that the empty information is enough, i.e., the empty comment has the meaning "We all believe you can do this yourself!". Why not to write it then explicitly in this form?
Comment: Here is where we digress (as it has often happened before :)). I see things in black and white and you in shades. However, I hope, we agree that the default meaning of a closed post with the empty comment for the OP is "You aren't welcome here". (We can talk about the difference between "you" and "this particular question of yours", but, frankly speaking, IMHO, the cases when one person can ask questions of wide range of interest and difficulty are pretty rare). Anyway, I guess we can see each other's point despite very different usage of language ;).
Comment: I do not consider everybody falling either under "reasonably clever reader" (of MO) and "too stupid or too lazy to waste my time on." Thus, I do not consider your statement regarding the compatibility as valid.
Comment: I agree regarding what one typically will infer from a closure without a comment. And, I almost never voted to close anything without either leaving a comment or there already being one I found alright. The only point of difference, if it is one, is that I do not think the *only* options are leaving *mathematical* information or telling them they will be able to solve it themselves. But, for example, one can also tell them that they could ask this elsewhere.
Comment: Sure. However, if you think of the time the person needs to read your suggestion to ask elsewhere, to ask elsewhere, to get a (possibly wrong because MO has more qualified people) answer, etc., and the time you need to type essentially the full solution, you'll realize that you value your time at least 100 times as much as his time. There are people for which I would agree with this comparison, as far as my own time is concerned, but they  all belong to the two categories I mentioned (in my classification). :)
Comment: OPs time and the person closing time are not the only relevant quantities here. When I want to optimize for my time, I simply ignore such things completely. (Which actually is what I do since some while mainly, since for reasons not needing discussion now, I reevaluted the value of the other quantities.) Sometimes it took me more time to write the comment to explain that they should ask elsewhere, than it would have taken to sketch an answer to the question. It is not as black-and-white, indeed. But, I think, essentially we agree anyway. :-)
Answer: It is considered bad form (at least by some) to answer off-topic question.
This applies mainly to proper answers, but one reason being that receiving answers encourages to come back with more questions, it extends to answers in comments. (Added: The answer appearing while I type confirms this view.)
That being said, certainly a hint here or there occurs with some frequency and is not considered as some violation of a policy.
However, some more points to consider against giving too much information in comments (sometimes I do this myself, also see at the end):

It can happen that one comment is not enough. Then there are requests for clarfication. Maybe even an edit of the question, keeping it still longer visible and so on.
Until now I only gave reasons why it is not good "for MO" but I feel it is not only this. It can also be bad for OP. There is a site math.SE where many questions that are off-topic here as too low level but otherwise reasonable (such as this one, I think) are perfectly on-topic. And there they would typically receive a proper or even several good answers. And not just some quick comment.
Giving a quick answer might have as effect that OP does not ask there and get a better answer.  Also, this might not be the only question an OP has, and the next ones will likely also fit better there on math.SE. I think the best course of action is to direct such posters, having reasonable math questions but not at the level appropriate for MO, to math.SE as directly as possible. (If not via a proper migration, just via telling them about the other site.)

There can be cases where sending an OP to math.SE is not optimal. For example, the question could be very unclear or likely mistated or some other things. In these cases I sometimes leave a comment making OP aware of these issues, with the encouragement to fix them first and then ask on math.SE if still needed.
So, in brief, while I do not consider it as a big problem if people answer off-topic questions a bit in comments, I do not think it is good to do so in general also as most of the time it seems to me it is not even the most helpful course of action for OP.


How to run ground, for electric supplied by generator and batteries through a inverter

Question: I have a panel that is powered from the generator, it runs my major appliances. One of the circuits feeds my inverter/charger , which charges my batteries. A 2nd. panel receives power from the batteries, through the inverter, and powers rest of house at 110 volt.   Should I keep all grounds on their own bars?.(separate from neutral) Connect ground bars from one box to other?, and run wire to ground rod outside?.           I have a Trace 2.5 KW impulse correction FET power inverter, Model 2524. I use a Honda 2000 Inverter generator, or Black Max 3000 standard generator. Plug in connection runs to panel.                       The neutral feeds the neutral bar in the appliance panel, positive feeds the breakers, and ground feeds a ground bar. The neutral and ground are not bonded. Wire from neutral bar feeds input on charger/inverter. Positive from one of the breakers feeds the positive input, and ground from the ground feeds the inverter safety ground. Next the inverter feeds another panel. Positive from output on the inverter feeds the breakers on my other panel, a neutral feeds a neutral bar, a ground comes from the safety ground on the inverter, and feeds a ground bar. In this box the neutral bar and ground bar are bonded through a screw in the neutral bar. This panel runs my lights, TV, pump, etc..
Comment: Can you include the make and model of the inverter/charger?
Comment: What make and model is your generator for that matter?
Comment: Is your generator set up with its neutral/ground bond jumper installed or removed? (Most ship with it installed per OSHA requirements for jobsite/... use)
Comment: Also, I take it this is an off-grid setup? Or are you transferring the inverter/charger AC input between generator and mains?
Answer: You are the electric utility -- thrice over!
Your configuration, with a generator and an inverter/charger, requires special care as you have not one, not two, but three electrical systems, all isolated from each other and completely off the mains electrical grid.  This is outside the norm for a residence, and requires careful application of the NEC rules for separately derived systems starting in 250.30.
Start with the easy stuff first
The easy part of this all is making sure that all the panelboard (aka load center/electrical panel) cabinets, the inverter's safety earth terminal, and the generator frame are all solidly connected together.  This makes sure you have an effective fault-current path everywhere it's needed as per 250.4(A)(5) and 250.92.  These conductors can be sized as per 250.122 in your case due to 250.102(D) and this rule from 250.32(A)(2):

A supply-side bonding jumper shall not be required to be
  larger than the derived ungrounded conductors.

Getting down to earth (ground)
You'll need a grounding electrode, of course.  This defaults to the metal-cold-water-pipe electrode (or structural steel, but you don't have that) in 250.30(A)(4), but I'd put another 250.52(A)-compliant one in to protect against plumber-induced losses of grounding, as they can leave your system completely floating which is a problem if lightning strikes nearby.
Since you have multiple separately derived systems, though, this is where things get hairball.  You'll either need to:

Run completely separate grounding electrode conductors from the generator grounding electrode attach point and inverter AC output bonding point to each of your grounding electrode(s).  This is straightforwardly permitted by 250.30(A)(6), but can lead to a proverbial spaghetti bowl of grounding electrode conductors, a minimum of four in your case, all of which must be at least as large as required by 250.66.
Or, run a single grounding electrode bus conductor between all the grounding electrodes and then tap it with 250.66-compliant conductors to feed the various grounding electrode attach points.  This bus conductor must be enormous though, as 250.30(A)(6)(a) requires it to be a minimum of 3/0 copper or 250kcmil aluminum.  That's the same size as a 200A service conductor!

In any case, you'll need to use listed grounding clamps or exothermic welds to make all grounding electrode and grounding electrode bus connections.
Bonding it all together
You'll now need to make sure that your supply bonds are in the correct places, and nothing's cross-wired between your grounds and your neutrals.  This means that you will need to practice good ground bar discipline -- both of your panels must have separate ground and neutral bars, with all the neutrals going to the neutral bar and all the grounds going to the ground bar.  Typical residential-sparky-in-a-hurry slobbering of everything onto one bar will not fly here!
First, the generator in your case is supplying the ground-to-neutral bond for its part of the system.  This means that you must pull the service bond out of the panel for the generator-powered stuff, wherever it might be (on a modern panel, it'll be a green screw in the neutral bar).  You will also need to install a ground bar kit into the panel if one is not present already and transfer all the ground wires to the new ground bar.
Second, thankfully, since you are dealing with a 24V DC system that is derived from a grounded AC system by a rectifier (battery charger), you don't need to bond the DC system to ground (as per 250.162(A) including Exception 2).  I would make sure that any metallic, non-current-carrying parts that may short to the DC system, such as metal battery racks, are bonded to the generator (inverter/charger AC input) system ground, though.
Finally, since your inverter's AC output is floating, you'll need to bond it to ground somewhere as per 250.20(B) point 1.  This can either be at the inverter with a jumper from the inverter output to both the inverter safety ground terminal and the grounding electrode conductors for the inverter system, or at the panelboard using the green screw or link (i.e. configuring the inverter-circuits panelboard as service equipment) as well as terminating the grounding electrode conductors onto the panelboard ground bar instead of the inverter bonding jumper.
Comment: I have added more on how my off grid system is wired. A ground wire comes from the generator supplied appliance panel ground bar (not bonded to neutral bar) to the inverter safety ground, then another ground wire comes off the inverter safety ground and goes to the inverter supplied panel ground bar. In this panel the ground bar is bonded to the neutral bar by a screw. Can I attach a grounding wire that goes to a grounding rod at the inverter safety ground? There is a large lug ,that is jumper to the inverter safety ground terminal at this location.
Comment: @JoelB -- you'll want to run wires from the generator earthing terminal and the inverter panel ground bar to your grounding electrode(s).
Comment: I presently have not attached the bonding screw in the 2nd panel, If I do it will bond to the ground bar in this panel, but will also bond to the first panel ground bar through the inverter safety ground connection.  This will lead to a connection of the generator neutral output (ground and neutral are bonded at generator) to the inverter output neutral in the 2nd panel at the neutral bar. Is this correct?.
Comment: @JoelB -- that's a good point, and one I've considered briefly in the context of isolation transformers as well.  It sounds worth its own question here...
Answer: In my case, I connect earth grounds all together between the house and the inverter.  In your case, I presume that you have the generator grounded as well?
Be sure to use an outlet tester (the kind with 3 LEDs) to check that you have done it correctly.
Comment: This guy has 3 separately derived systems on his hands -- hooking the earth ground wires up is the easy part of his job!


Why is it a good idea that X.509 digital certificates have an expiry date?

Question: What is the benefit of having certificates expire at some fixed date?
Comment: How else would you make money as a CA? ;-)
Comment: Deadman switch. Fails safe.
Comment: Good question. BTW does X.509 claims check expiration date?
Answer: The official reason why certificates expire is because of revocation. A certificate is "revoked" when its issuer asserts that the certificate contents are no longer to be trusted, for some reason which needs not me specified. It is like a "cancel" from the CA: the CA signed the certificate, but now regrets it.
A common reason for revocation is when the private key is suspected to have been stolen (e.g. a smart card was lost, so it might be in the wrong hands).
Revocation works by adding the certificate serial number in the Certificate Revocation Lists that the CA publishes regularly. These CRL are signed (usually by the CA) and people who use certificates (e.g. Web browsers, for SSL server certificates) are supposed to automatically download the newest CRL to see whether the certificate they are about to use has been revoked or not.
Without expiration dates, CRL would grow indefinitely, and become too bulky for usage. With expiration, certificates which are expired are removed from the CRL; in that sense, certificate revocation behaves like an hastened expiry. So there you have it: certificates expire to keep CRL small.
(If certificates were very short-lived, and renewed every week or even every day, then we could get away with no revocation support at all, which would be cool, but this would require some sort of automatic renewal, which has its own set of potential issues.)

CRL size is the theoretical reason. The practical reason is that commercial CA really love it when customers have to buy a renewal every year.
An argument can also be made about key sizes and algorithms. Certificate renewal is a good opportunity for enforcing a new algorithm, or a larger key than previously. This is a smoother mechanism than having to revoke old certificates when their key size becomes "too small for comfort" with regards to cryptanalysis advances.
Answer: Digital certificates are used to verify identities and affiliations online. People change jobs, students graduate, businesses fail or change ownership, private keys get leaked, and any number of other things may happen that would cause a particular certificate to stop being an accurate way to verify an identity. Certificates expire so that people using them can be sure that the information in them is at least somewhat up to date.
Answer: Same reason your driving licence expires. You may have existed last time you renewed, with that name, that address, that date of birth, that appearance, (and you may have been able to drive ;-)) but that state cannot rationally be expected to continue unchanged forever. So it has a renewal. Same applies to a digital certificate. It identifies an entity that exists, has a certain name, has a chain of CAs that are prepared to vouch for the next one down, etc ... None of that persists forever.
Answer: It's just because private keys can get stolen/compromised over time. So, if someone steals your key (e.g. a naughty employee who's leaving the company), their stolen key is only valuable for a limited time.
Sure, you can revoke a certificate once you know it's been stolen, but if you don't realise it's been stolen, then expiration helps.
HTH


Is there any Biblical reference strictly speaking about God being timeless?

Question: I've heard a lot, mainly from apologists, the notion that God is Timeless (Little example). So, this is an assumption on the philosophical ground, but is there a theological ground for it? Any verse in the scriptures that talks about His relatioship with time, or we can assume that He is timeless just because He is the Creator of everything and He is Eternal?
Comment: My first encounter with this idea was reading C.S. Lewis (Mere Christianity), who may have gotten the idea from Augustine. Here is an article that disagrees with Lewis: http://www.dynamicfreetheism.com/CSLewis.html
Comment: This article says that the idea originated with the Greeks and is not Biblical: http://kgov.com/is-God-outside-of-time
Comment: This article defends the idea of God's timelessness: http://www.reasonablefaith.org/divine-timelessness-and-personhood
Answer: While how much philosophy has influenced the church on this can be debated,  one only has to look to Scripture to see that God clearly operates outside time.
The term "outside time" may mean different things to people. To to clarify I'm saying that in order to be considered outside time one must display the ability to

Control time.
Independent of time, not bound by its linear restrictions.
Understand and perceive events in time, if not time itself, in a way that is,  again,  not restricted by the laws of time as they apply to us.

Creation
First,  we have the idea that God created the universe. As physics has advanced we have learned more and more how time is an integral part of our universe, tied together with how it operates. So when God created the universe it seems plain that he created time as well.  And if he has dominion over all creation,  then that would include time.  This may be the simplest and yet strongest argument.
Controlling Time
If that seems to be too much philosophical reasoning,  which may or may not be influenced,  then consider what scripture has to say.
We see in Joshua 10 that the sun and moon stopped. Now,  time still passed in some way, allowing the Israelites to continue the fight,  but this shows extreme control over creation.  Many speculate that the only way to do such a thing without causing a massive cataclysm to the entire solar system would be to actually stop time around the Israelites,  or to accelerate it so it seemed it stopped around then.
Either way,  there is control of time in the ability to stop,  slow,  accelerate time simply violate physics entirely without damage.
A similar event happens in 2 Kings 20 when God moves the shadow backwards as a sign to Hezekiah.
Independent of Time
The OP seems to accept God's eternal nature. To be eternal is to be independent of time. It has no effect on him as he never changes.
Psalm 90 has much to say including in verse 2:

from everlasting to everlasting you are God.

Perceiving Events from Outside
We also see prophecy in scripture where God has clear knowledge of our future as if it was the past.
Isaiah 46:9-10

I am God, and there is none like me,10 declaring the end from the beginning and from ancient times things not yet done,

Isaiah 48:5

I declared them to you from of old, before they came to pass I announced them to you,

Psalm 139:16

Your eyes saw my unformed substance;
  in your book were written, every one of them,
  the days that were formed for me,
  when as yet there was none of them.

Also it seems time does not pass for God the way out does for us.
2 Peter 3:8

But do not overlook this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day.

Conclusion
There is lots of internal evidence in scripture,  if you accept it on its own merit,  that suggests that God is independent, in control, and able to perceive all of time.
Comment: Oh,  forgot to mention Hezekiah in 2 Kings 20, when time may have gone backwards!
Comment: `may being bound by its linear restrictions` doesn't make sense in context.  Do you perhaps mean "not being bound ..."?  Also, lease do edit 2 Kings 20 into your answer instead of adding it as a comment.
Comment: Thanks,  both of you. Wasn't happy with 2) anyway,  I hope I sharpened the definition.