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54,596 | Ultrapreneur | 2007-09-14T15:04:38 | Microsoft, Blackberry and a multibillion-dollar rumour | http://www.intergovworld.com/article/d1e80d590a010408017a95c67999fcd0/pg1.htm | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,598 | tomh | 2007-09-14T15:10:39 | SilverStripe - Open Source CMS, Has Support From Google | null | http://www.readwriteweb.com/archives/silverstripe_open_source_cms_google_summer_of_code.php | 3 | 2 | [
54653
] | null | null | null | null | null | null | null | null | null | train |
54,602 | ivankirigin | 2007-09-14T15:15:25 | Falcon 1: how to get something into orbit | null | http://www.spacex.com/falcon1.php | 4 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,615 | tx | 2007-09-14T15:45:08 | Programmers and Business (cost of dumb programmers) | http://kontsevoy.blogspot.com/2007/09/on-programmers-and-businesses.html | 3 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,625 | nickb | 2007-09-14T16:00:38 | Craig Mundie, Bill Gates' successor: "...there would have been no Google without Microsoft." | null | http://www.apcmag.com/7161/interview_craig_mundie_microsofts_technology_chief_taking_over_from_bi | 1 | 0 | null | null | null | no_error | APC issue 538 (November) is on sale now! | 2024-04-01T21:37:07+00:00 | APC magazine |
Click here for APC's exclusive full-version downloadsStop thinking of AI as a threat and start using it for work. In this essential issue, APC reveals how AI is being used in a variety of industries. We’ve interviewed people who are using AI across a wide cross-section of professions to find out how it’s transforming the way they work. From teachers saving hours on lesson planning, to a gardener despatching invoices from voice memos, to market researchers using AI to rapidly scale the quality of research they’re able to conduct, AI is making an enormous difference in the workplace.By all means spend your time fretting over when AI is going to take your job. Or get ahead of the curve and find out how to exploit it for yourself. You never know, it might just work out.Plus, in this issue of APC, AMD and Intel have traditionally released new processors every year, often with the biggest updates arriving for the summer season. 2024 continues that trend, but there are new processors, and there are new processors. In what has become mostly a two-year cadence, both AMD and Intel have major architectural overhauls going on, promising bigger changes than the off-year refreshes.We also take a trip in the Wayback Machine, and look at Apple’s rarest and most overlooked products. Nestled among Apple’s many blockbuster products, you’ll also find many products that didn’t quite catch in the same way as the iPhone. Some were years ahead of their time, some were ideas that Apple simply decided not to explore further, and some really should have been left in the meeting room.Get your fill of all the hottest new gear from Europe’s biggest consumer technology show, as IFA celebrated its 100th anniversary this year, but more importantly it produced a bunch of products we’re now desperate to review. Here are our picks.All that plus loads more to read, with reviews of the latest and greatest new gear, all in issue 538 (November) of APC – on sale now!Read APC and thousands more Aussie and international magazines on Readly | 1-month free trial, then AU$11.99p/m(Image credit: Readly)There's a new way to read APC and all your other favourite Future Australia magazines! Pick up a subscription to Readly for AU$11.99p/m and you'll get unrestricted, all-you-can-read digital access to all the latest issues of APC, plus over 5,000 other Australian and international magazines. You can browse and read any issue on your PC, Mac, tablet or smartphone. VIEW DEALSign up to be the first to know about unmissable Black Friday deals on top tech, plus get all your favorite TechRadar content.Subscribe to APC's print edition and save!Subscribe to the print edition of APC magazine and you'll enjoy a greatly-reduced cover price, plus free delivery directly to your door. Visit techmags.com.au for full details:(Image credit: Future)Get the digital edition for your tabletAlternatively, APC is also available in digital edition to read on your iOS or Android device. To purchase individual issues or take up a subscription, simply follow these links to the Apple Newsstand or Zinio:(Image credit: Apple)(Image credit: Zinio)Click here for APC's exclusive full-version downloadsGot a question for the APC editorial team? You can get in touch with us by sending an email to [email protected].
| 2024-11-08T13:59:53 | en | train |
54,627 | amichail | 2007-09-14T16:07:57 | Four brilliant mathematicians whose genius has profoundly affected us but which drove them insane. [bbc] | http://video.google.com/videoplay?docid=-3503877302082311448 | 19 | 14 | [
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|
54,628 | Leon | 2007-09-14T16:10:03 | Great Computer Science Video Lectures | For those who haven't seen the site, it contains a great collection of video lectures, with many notable computer science lectures. If you want to brush up or learn something new, check it out.<p>Right now I'm personally enjoying the series on pattern recognition, specifically Gregory Chaitin's talks, but there are many areas to choose from.<p>The site also contains other areas of interest, go explore! | http://videolectures.net/Top/Computer_Science/ | 1 | 0 | null | null | null | missing_parsing | Page Not Found - Videolectures | null | null | Oops...There is nothing here..We could not find the page you are looking for. | 2024-11-08T08:25:55 | null | train |
54,630 | nickb | 2007-09-14T16:11:24 | Walt Mossberg Reviews Dell Ubuntu: "...still too rough around the edges..." | null | http://ptech.allthingsd.com/20070913/linuxs-free-system-is-now-easier-to-use-but-not-for-everyone/ | 17 | 25 | [
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54,631 | divia | 2007-09-14T16:13:33 | Checkers Is Solved: Perfect play by both sides leads to a draw | null | http://www.sciencemag.org/cgi/content/abstract/1144079 | 18 | 5 | [
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54,632 | gscott | 2007-09-14T16:16:36 | Carmel Valley venture lender fills 'gap between banks and private equity' | In the six years since Miller and Wilson co-founded Huntington, the firm has provided $29.2 million in funding to 25 companies based mostly in Southern California. | http://www.signonsandiego.com/news/business/20070914-9999-1b14lender.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,644 | nreece | 2007-09-14T16:56:38 | How to make money off Facebook Apps? | Just wondering, what different revenue channels are possible with a Facebook application? Say: advertising (not sure if its allowed to embed it in), direct sales (the existing $1 gifts app for example), referrals/affiliates etc.? | 1 | 3 | [
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|
54,645 | kkim | 2007-09-14T17:02:58 | The mystery of China's celtic mummies | http://news.independent.co.uk/world/asia/article1222214.ece | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,649 | kkim | 2007-09-14T17:11:36 | YouTube, Viacom bow to light-sabre-wielding defender of online justice | null | http://www.theregister.com/2007/09/13/youtube_viacom_bow_to_light_sabre_wielding_video_maven/ | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,650 | nickb | 2007-09-14T17:11:57 | Most Science Studies Appear to Be Tainted By Sloppy Analysis | http://online.wsj.com/article/SB118972683557627104.html?mod=most_emailed_day | 20 | 15 | [
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|
54,656 | nickb | 2007-09-14T17:26:27 | Interview with Peter Norvig, Google's Head of Research: "We Don't Do Hardware" | http://www.custompc.co.uk/features/601291/an-interview-with-googles-head-of-research.html | 12 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,658 | mk | 2007-09-14T17:28:51 | Mint.com: The most useful site I've seen in a while | I've recently had the opportunity to try out the mint.com private beta and I have to say that it is really awesome. Hopefully it changes the way I spend my money(allowing me to save more). | http://mint.com/ | 3 | 3 | [
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54,666 | nreece | 2007-09-14T18:04:30 | Hackers welcome at software companies (Forbes report) | http://www.rediff.com/money/2007/sep/14forbes.htm | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,667 | Ultrapreneur | 2007-09-14T18:09:14 | An open letter to Mark Zuckerberg (Facebook) | http://www.aarongreenspan.com/letter/index.html | 9 | 8 | [
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|
54,671 | byrneseyeview | 2007-09-14T18:29:41 | The Puritan Paradox: Why Sin Pays on Wall Street | http://www.byrneseyeview.com/marketview/the_puritan_paradox.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,674 | naish | 2007-09-14T18:38:57 | Cringely: Google planning to build a 700-MHz and WiFi mesh network? Watchout ISPs and telcos! | http://www.pbs.org/cringely/pulpit/2007/pulpit_20070914_002928.html | 2 | 2 | [
54688
] | null | null | null | null | null | null | null | null | null | train |
|
54,679 | markpeterdavis | 2007-09-14T18:49:12 | In Your First Meeting With A VC Don't Ramble | In previous posts I have talked about the various ways in which you can stay focused on the objective of your first meeting. However, one way in which entrepreneurs frequently get off track is by trying to squeeze as much information as they can into the conversation with the hope that some of the details will hook the VC. | http://getventure.typepad.com/markpeterdavis/2007/09/do-not-ramble.html | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,681 | Ultrapreneur | 2007-09-14T18:51:36 | Is The Bubble Back? | http://www.internetnews.com/bus-news/article.php/3606676 | 1 | 1 | [
54689
] | null | null | null | null | null | null | null | null | null | train |
|
54,682 | brett | 2007-09-14T18:55:33 | Apple Excludes ITunes Music From $100 IPhone Credit | null | http://www.bloomberg.com/apps/news?pid=20601087&sid=ach7AweWoeyo&refer=home | 1 | 1 | [
54782
] | null | null | null | null | null | null | null | null | null | train |
54,687 | myoung8 | 2007-09-14T19:04:04 | eHarmony? IPO? Oh god... | Say it ain't so. | http://money.cnn.com/2007/09/14/magazines/fortune/fastforward_eharmony.fortune/?postversion=2007091413 | 4 | 4 | [
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54,692 | transburgh | 2007-09-14T19:18:14 | Why you (entrepreneurs) should trust your gut. Always. | null | http://www.foundread.com/view/why-you-should-trust | 18 | 12 | [
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54,693 | Ultrapreneur | 2007-09-14T19:23:45 | What is Technical Harassment? | In our complex technical environment there are many opportunities for a competent technical individual to be the subject of technical harassment. Sometimes it can be so subtle that you may not even be aware you are being harassed. Worse yet, you may inadvertently technically harass another person by accident. <p>Following are some guidelines to help you determine if you are being technically harassed. <p>If you are repeatedly asked the same technical question you may be the victim of technical harassment. While it is most common to be asked the question repeatedly within the same conversation, some instances have been identified of habitual technical harassment. Habitual technical harassment is not uncommon and has been known to exhibit group tendencies where members of a group may ask the same question repeatedly. Untreated, these instances of group technical harassment can continue for years. <p>If you are asked a technical question by a non-technical person and they do not write your answer down it is likely the question is frivolous. Most non-technical people are not capable of remembering a true technical answer for more than 30 seconds. <p>If you are forced into a discussion where a person uses more than three (3) buzzwords in one sentence the person is most likely a fake and you are the unwitting victim of technical harassment. One note of caution, competent technical people have been known to inadvertently use buzzwords after reading mindless drivel like PC Week or LAN Times. If the person has been known to use more common technical terms in the past such as "stuff" and "things", they are most likely victim of computer magazine brainwashing. <p>If during a troubleshooting session a person uses the term "trick". For example "maybe we could trick the database into thinking it has been updated". This is a sure sign of technical harassment. <p>If a person explains that a needed feature will be provided by a vendor and that person is nontechnical then you are at risk of being technically harassed. If you believe that person, you have definitely been technically harassed, if you don't believe them you have only been technically annoyed. <p>If when trying to resolve a technical problem with a product from a vendor and you are instructed to call the salesman that sold us the product you are being set up for technical harassment. It is a common reaction for a non-technical person when they have purchased technical equipment to call another non-technical person. The dialogue between two nontechnical people usually provides some sense of comfort that they aren't the only ones who are confused.
| 10 | 2 | [
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|
54,702 | jnestor | 2007-09-14T19:50:58 | Killing deal from Jason Potash | http://adsense-diary.blogspot.com/2007/09/killing-deal-from-jason-potash.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,705 | nickb | 2007-09-14T19:56:35 | SCO Files For Chapter 11 Bankruptcy | http://www.groklaw.net/article.php?story=20070914152904577 | 24 | 8 | [
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|
54,710 | karzeem | 2007-09-14T20:21:18 | Wired's 101 Ways to Save Apple (from 1997, via FSJ) | http://www.wired.com/wired/archive/5.06/apple.html | 1 | -1 | null | null | true | null | null | null | null | null | null | null | train |
|
54,719 | amichail | 2007-09-14T20:40:02 | Bin Laden for president? | http://www-stu.calvin.edu/chimes/article.php?id=2895 | 1 | 2 | [
54741
] | null | null | null | null | null | null | null | null | null | train |
|
54,723 | amichail | 2007-09-14T20:49:02 | Stunning CS theory result: Polynomial Hierarchy Collapses [pdf] | http://www.scottaaronson.com/writings/phcollapse.pdf#page=1 | 7 | 3 | [
54821
] | null | null | null | null | null | null | null | null | null | train |
|
54,727 | dpapathanasiou | 2007-09-14T20:57:52 | Canning Spam: Why is it so difficult to prevent junk e-mail? | http://www.economist.com/displaystory.cfm?story_id=9805795 | 3 | 4 | [
54887,
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] | null | null | missing_parsing | Canning spam | 2007-09-14T00:00:00.000Z | The Economist | FOR two days last month, the largest spam (unsolicited e-mail) attack ever detected wreaked havoc on e-mail networks throughout America, clogging in-boxes and bringing countless corporate systems to their knees. The anti-spam filters used to protect e-mail users from scam merchants offering bogus Viagra pills, fake Rolex watches and worthless penny stocks were simply overwhelmed. On August 7th, the day the attack began, the total amount of junk e-mail being delivered jumped 53%. By August 9th, the daily volume was 445% higher than usual. Then it suddenly ceased. | 2024-11-08T10:59:28 | null | train |
|
54,732 | byrneseyeview | 2007-09-14T21:19:43 | Great design sense and a knack for sales won't save you (if your best friend is a penny-stock tout) | http://nymag.com/nymetro/news/bizfinance/biz/features/4406/ | 7 | 19 | [
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|
54,735 | transburgh | 2007-09-14T21:27:42 | Strategic Tool: How to use the 'Scarcity Illusion' to boost your launch | null | http://www.foundread.com/view/strategic-tool-how | 2 | 0 | null | null | null | no_article | null | null | null | null | 2024-11-08T16:30:06 | null | train |
54,747 | brett | 2007-09-14T22:13:16 | Basic JS/CSS to for iPhone orientation detection | null | http://earthcode.com/blog/2007/09/iphone_web_dev.html | 1 | 0 | null | null | null | fetch failed | null | null | null | null | 2024-11-08T17:27:55 | null | train |
54,760 | axiom | 2007-09-14T23:52:33 | A Business Idea for Anyone Who Wants It | Steen Levitt, co-author of Freakonomics, provides the algorithms he used to detect cheating on standardized tests by teachers at public schools. He suggests that with the No Child Left Behind act there might be a solid business idea in developing software that looks for statistical anomalies in test scores in order to detect cheating.
Teachers might cheat by inflating the scores of their students in order to secure more funding for their school. | http://freakonomics.blogs.nytimes.com/2007/09/12/a-business-idea-for-anyone-who-wants-it/ | 8 | 2 | [
54770
] | null | null | null | null | null | null | null | null | null | train |
54,761 | nickb | 2007-09-14T23:54:23 | Scaling Twitter: Making Twitter 10000 Percent Faster | null | http://highscalability.com/scaling-twitter-making-twitter-10000-percent-faster | 20 | 1 | [
55078
] | null | null | no_error | Scaling Twitter: Making Twitter 10000 Percent Faster - High Scalability - | 2009-06-28T05:46:00.000Z | Todd Hoff |
Example
Jun 27, 2009
— 7 min read
Update 6: Some interesting changes from Twitter's Evan Weaver: everything in RAM now, database is a backup; peaks at 300 tweets/second; every tweet followed by average 126 people; vector cache of tweet IDs; row cache; fragment cache; page cache; keep separate caches; GC makes Ruby optimization resistant so went with Scala; Thrift and HTTP are used internally; 100s internal requests for every external request; rewrote MQ but kept interface the same; 3 queues are used to load balance requests; extensive A/B testing for backwards capability; switched to C memcached client for speed; optimize critical path; faster to get the cached results from the network memory than recompute them locally.Update 5: Twitter on Scala. A Conversation with Steve Jenson, Alex Payne, and Robey Pointer by Bill Venners. A fascinating discussion of why Twitter moved to the Java JVM for their server infrastructure (long lived processes) and why they moved to Scala to program against it (high level language, static typing, functional). Ruby is used on the front-end but wasn't performant or reliable enough for the back-end.Update 4: Improving Running Components at Twitter by Evan Weaver. Tells how Twitter changed their infrastructure to go from handling 3 requests to 139 requests a second. They moved to a messaging model, asynchronous process, 3 levels of cache, and moved their middleware to a mixture C and Scala/JVM.Update 3: Upgrading Twitter without service disruptions by Gojko Adzic. Lots of good updates on the new Twitter architecture.Update 2: a commenter in Twitter Fails Macworld Keynote Test said this entry needs to be updated. LOL. My uneducated guess is it's not a language or architecture problem, but more a problem of not being able to add hardware fast enough into their data center. The predictability of this problem is debatable, but once you have it, it's hard to fix.Update: Twitter releases Starling - light-weight persistent queue server that speaks the MemCache protocol. It was built to drive Twitter's backend, and is in production across Twitter's cluster.
Twitter started as a side project and blew up fast, going from 0 to millions of page views within a few terrifying months. Early design decisions that worked well in the small melted under the crush of new users chirping tweets to all their friends. Web darling Ruby on Rails was fingered early for the scaling problems, but Blaine Cook, Twitter's lead architect, held Ruby blameless:
For us, it’s really about scaling horizontally - to that end, Rails and Ruby haven’t been stumbling blocks, compared to any other language or framework. The performance boosts associated with a “faster” language would give us a 10-20% improvement, but thanks to architectural changes that Ruby and Rails happily accommodated, Twitter is 10000% faster than it was in January.
If Ruby on Rails wasn't to blame, how did Twitter learn to scale ever higher and higher?Update: added slides Small Talk on Getting Big. Scaling a Rails App & all that JazzSite: http://twitter.com
Information Sources
Scaling Twitter Video by Blaine Cook.
Scaling Twitter Slides
Good News blog post by Rick Denatale
Scaling Twitter blog post Patrick Joyce.
Twitter API Traffic is 10x Twitter’s Site.
A Small Talk on Getting Big. Scaling a Rails App & all that Jazz - really cute dog picks
The Platform
Ruby on Rails
Erlang
MySQL
Mongrel - hybrid Ruby/C HTTP server designed to be small, fast, and secure
Munin
Nagios
Google Analytics
AWStats - real-time logfile analyzer to get advanced statistics
Memcached
The Stats
Over 350,000 users. The actual numbers are as always, very super super top secret.
600 requests per second.
Average 200-300 connections per second. Spiking to 800 connections per second.
MySQL handled 2,400 requests per second.
180 Rails instances. Uses Mongrel as the "web" server.
1 MySQL Server (one big 8 core box) and 1 slave. Slave is read only for statistics and reporting.
30+ processes for handling odd jobs.
8 Sun X4100s.
Process a request in 200 milliseconds in Rails.
Average time spent in the database is 50-100 milliseconds.
Over 16 GB of memcached.
The Architecture
Ran into very public scaling problems. The little bird of failure popped up a lot for a while.
Originally they had no monitoring, no graphs, no statistics, which makes it hard to pinpoint and solve problems. Added Munin and Nagios. There were difficulties using tools on Solaris. Had Google analytics but the pages weren't loading so it wasn't that helpful :-)
Use caching with memcached a lot.- For example, if getting a count is slow, you can memoize the count into memcache in a millisecond.- Getting your friends status is complicated. There are security and other issues. So rather than doing a query, a friend's status is updated in cache instead. It never touches the database. This gives a predictable response time frame (upper bound 20 msecs).- ActiveRecord objects are huge so that's why they aren't cached. So they want to store critical attributes in a hash and lazy load the other attributes on access.- 90% of requests are API requests. So don't do any page/fragment caching on the front-end. The pages are so time sensitive it doesn't do any good. But they cache API requests.
Messaging- Use message a lot. Producers produce messages, which are queued, and then are distributed to consumers. Twitter's main functionality is to act as a messaging bridge between different formats (SMS, web, IM, etc).- Send message to invalidate friend's cache in the background instead of doing all individually, synchronously.- Started with DRb, which stands for distributed Ruby. A library that allows you to send and receive messages from remote Ruby objects via TCP/IP. But it was a little flaky and single point of failure.- Moved to Rinda, which a shared queue that uses a tuplespace model, along the lines of Linda. But the queues are persistent and the messages are lost on failure.- Tried Erlang. Problem: How do you get a broken server running at Sunday Monday with 20,000 users waiting? The developer didn't know. Not a lot of documentation. So it violates the use what you know rule.- Moved to Starling, a distributed queue written in Ruby. - Distributed queues were made to survive system crashes by writing them to disk. Other big websites take this simple approach as well.
SMS is handled using an API supplied by third party gateway's. It's very expensive.
Deployment- They do a review and push out new mongrel servers. No graceful way yet.- An internal server error is given to the user if their mongrel server is replaced.- All servers are killed at once. A rolling blackout isn't used because the message queue state is in the mongrels and a rolling approach would cause all the queues in the remaining mongrels to fill up.
Abuse- A lot of down time because people crawl the site and add everyone as friends. 9000 friends in 24 hours. It would take down the site.- Build tools to detect these problems so you can pinpoint when and where they are happening.- Be ruthless. Delete them as users.
Partitioning- Plan to partition in the future. Currently they don't. These changes have been enough so far.- The partition scheme will be based on time, not users, because most requests are very temporally local.- Partitioning will be difficult because of automatic memoization. They can't guarantee read-only operations will really be read-only. May write to a read-only slave, which is really bad.
Twitter's API Traffic is 10x Twitter’s Site- Their API is the most important thing Twitter has done.- Keeping the service simple allowed developers to build on top of their infrastructure and come up with ideas that are way better than Twitter could come up with. For example, Twitterrific, which is a beautiful way to use Twitter that a small team with different priorities could create.
Monit is used to kill process if they get too big.
Lessons Learned
Talk to the community. Don't hide and try to solve all problems yourself. Many brilliant people are willing to help if you ask.
Treat your scaling plan like a business plan. Assemble a board of advisers to help you.
Build it yourself. Twitter spent a lot of time trying other people's solutions that just almost seemed to work, but not quite. It's better to build some things yourself so you at least have some control and you can build in the features you need.
Build in user limits. People will try to bust your system. Put in reasonable limits and detection mechanisms to protect your system from being killed.
Don't make the database the central bottleneck of doom. Not everything needs to require a gigantic join. Cache data. Think of other creative ways to get the same result. A good example is talked about in Twitter, Rails, Hammers, and 11,000 Nails per Second.
Make your application easily partitionable from the start. Then you always have a way to scale your system.
Realize your site is slow. Immediately add reporting to track problems.
Optimize the database. - Index everything. Rails won't do this for you. - Use explain to how your queries are running. Indexes may not be being as you expect.- Denormalize a lot. Single handedly saved them. For example, they store all a user IDs friend IDs together, which prevented a lot of costly joins.- Avoid complex joins.- Avoid scanning large sets of data.
Cache the hell out of everything. Individual active records are not cached, yet. The queries are fast enough for now.
Test everything. - You want to know when you deploy an application that it will render correctly.- They have a full test suite now. So when the caching broke they were able to find the problem before going live.
Long running processes should be abstracted to daemons.
Use exception notifier and exception logger to get immediate notification of problems so you can address the right away.
Don't do stupid things.- Scale changes what can be stupid.- Trying to load 3000 friends at once into memory can bring a server down, but when there were only 4 friends it works great.
Most performance comes not from the language, but from application design.
Turn your website into an open service by creating an API. Their API is a huge reason for Twitter's success. It allows user's to create an ever expanding and ecosystem around Twitter that is difficult to compete with. You can never do all the work your user's can do and you probably won't be as creative. So open you application up and make it easy for others to integrate your application with theirs.
Related Articles
For a discussion of partitioning take a look at Amazon Architecture, An Unorthodox Approach to Database Design : The Coming of the Shard, Flickr Architecture
The Mailinator Architecture has good strategies for abuse protection.
GoogleTalk Architecture addresses some interesting issues when scaling social networking sites.
| 2024-11-08T09:51:48 | en | train |
54,762 | nickb | 2007-09-14T23:54:45 | China emerges as leader in cyberwarfare | null | http://www.csmonitor.com/2007/0914/p01s01-woap.html?page=1 | 4 | 1 | [
54818
] | null | null | null | null | null | null | null | null | null | train |
54,764 | webbinator | 2007-09-15T00:00:18 | Invites to Yahoo's new social network, Mash | null | http://www.inviteshare.com/site.php?id=50 | 2 | 1 | [
54850
] | null | null | null | null | null | null | null | null | null | train |
54,765 | dhkim36 | 2007-09-15T00:01:39 | I want to make a video demo for my website. What are good programs/services/compani... to use? | null | 8 | 6 | [
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] | null | null | invalid_url | null | null | null | null | 2024-11-08T16:37:59 | null | train |
|
54,774 | scrollinondubs | 2007-09-15T00:33:24 | Trac and Subversion screencast: 20min to productivity | null | http://video.jumpbox.com/?app=trac | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,788 | NoMoreSnow | 2007-09-15T01:18:18 | Calculating valuation when using web-service back-end? | All,<p>For the YC funding application, I'm having difficulty determining valuation. The reason being that the back-end would use web-services for computing/storage (yeah, they do more than sell books :-)<p>Should I do an estimate based on an ideal system running at 100% processing usage? This may seem appropriate for a system that produces widgets, but mine mainly deals with running queries.<p>Thank you for your help!
NoMoreSnow | 1 | 0 | null | null | null | invalid_url | null | null | null | null | 2024-11-08T16:37:59 | null | train |
|
54,795 | paulgb | 2007-09-15T01:27:51 | Alternative Online Business Models | http://markevanstech.com/2007/09/13/alternative-online-business-models/ | 2 | 0 | null | null | null | fetch failed | null | null | null | null | 2024-11-08T09:51:25 | null | train |
|
54,803 | axiom | 2007-09-15T02:03:35 | Carnegie Mellon Red team (of DARPA Grand Challenge fame) to enter Google moon landing competition | http://www.cmu.edu/homepage/global/2007/summer/to-the-moon.shtml | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,810 | transburgh | 2007-09-15T02:34:19 | Get A Yahoo Mash Invitation At InviteShare | null | http://www.techcrunch.com/2007/09/14/get-a-yahoo-mash-invitation-at-inviteshare/ | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,816 | nickb | 2007-09-15T02:48:06 | The Biggest Ever BitTorrent Leak: MediaDefender Internal Emails Go Public | null | http://torrentfreak.com/mediadefender-emails-leaked-070915/ | 3 | 1 | [
54868
] | null | null | null | null | null | null | null | null | null | train |
54,819 | nickb | 2007-09-15T02:53:32 | Facebook suicide: the end of a virtual life | null | http://women.timesonline.co.uk/tol/life_and_style/women/body_and_soul/article2452928.ece | 3 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,820 | nickb | 2007-09-15T03:04:38 | Company Demos Personal Aircraft, Future Jetpack | null | http://www.networkworld.com/community/node/19485 | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,823 | amichail | 2007-09-15T03:27:50 | Trigonometry? No Way: These Teens Would Rather Toss a Ball | http://www.scottaaronson.com/writings/athletes.html | 20 | 4 | [
54907,
54844
] | null | null | null | null | null | null | null | null | null | train |
|
54,824 | redrory | 2007-09-15T03:30:11 | Does anyone else love to read StartUp blogs? | I find they give better advice, than the entrepreneur blogs.<p>I like Octopart's blog, and some one others.
Feel free to name your favs. | 1 | 0 | null | null | null | invalid_url | null | null | null | null | 2024-11-08T16:37:59 | null | train |
|
54,825 | nickb | 2007-09-15T03:33:00 | The human programmer | null | http://technically.us/code/x/the-human-programmer | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,827 | nickb | 2007-09-15T03:44:15 | Critique of DHH philosophy: "37signals' products tend to be so "opinionated" as to be anti-user" | null | http://storytotell.org/articles/2007/09/14/three-little-letters | 14 | 13 | [
54966,
55068,
55148
] | null | null | null | null | null | null | null | null | null | train |
54,834 | robg | 2007-09-15T04:14:54 | Ayn Rand's Literature of Capitalism | http://www.nytimes.com/2007/09/15/business/15atlas.html?ex=1347508800&en=8fc42c2f2603a791&ei=5090&partner=rssuserland&emc=rss | 33 | 93 | [
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] | null | null | null | null | null | null | null | null | null | train |
|
54,841 | nickb | 2007-09-15T05:11:58 | Mark Pilgrim: The longdesc lottery | http://blog.whatwg.org/the-longdesc-lottery | 3 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,848 | karzeem | 2007-09-15T05:49:45 | Why it's hard to communicate clearly in e-mail | http://www.andyrutledge.com/elements-of-communication-part-2.php | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,853 | aaroneous | 2007-09-15T07:43:46 | In late stage consumer markets, brand matters more than product | http://lsvp.wordpress.com/2007/09/14/in-late-stage-consumer-markets-brand-matters-more-than-product/ | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,855 | nreece | 2007-09-15T07:44:14 | The Oldest Business with Six Sigma Quality | http://www.itcinstitute.com/display.aspx?id=3091 | 2 | 1 | [
55738
] | null | null | null | null | null | null | null | null | null | train |
|
54,856 | nreece | 2007-09-15T08:03:15 | Google Proposes International Privacy Standard | http://www.dailytech.com/Google+Proposes+International+Privacy+Standard/article8880.htm | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,858 | brett | 2007-09-15T08:06:13 | Roller Skate Implementation | null | http://martinfowler.com/bliki/RollerSkateImplementation.html | 7 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,883 | danw | 2007-09-15T10:50:55 | O2 lights up EDGE - looks like theres no 3G iPhone | null | http://blog.suthakamal.com/2007/09/o2-lights-up-edge.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
54,886 | vlad | 2007-09-15T11:06:28 | More Students Attempting Masters Degrees Than Ever | http://www.nytimes.com/2007/09/12/education/12masters.html?ex=1347249600&en=571a16a5d2233d56&ei=5090&partner=rssuserland&emc=rss | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,888 | chmike | 2007-09-15T11:37:33 | Suing for patent on playlists? | http://arstechnica.com/news.ars/post/20070914-company-patents-playlists-sues-everyone.html | 3 | 1 | [
55151
] | null | null | null | null | null | null | null | null | null | train |
|
54,890 | nirs | 2007-09-15T12:55:17 | Unicode art on reddit | http://reddit.com/info/2pnpu/comments | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,901 | robg | 2007-09-15T13:43:24 | Living Your Dreams, in a Manner of Speaking - Lucid Dreaming | http://www.nytimes.com/2007/09/16/fashion/16lucid.html?ex=1347595200&en=b22d6639167a4baf&ei=5090&partner=rssuserland&emc=rss | 17 | 11 | [
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] | null | null | null | null | null | null | null | null | null | train |
|
54,905 | robg | 2007-09-15T14:00:44 | Do We Really Know What Makes Us Healthy? | http://www.nytimes.com/2007/09/16/magazine/16epidemiology-t.html?ex=1347595200&en=ce44168aa0044276&ei=5090&partner=rssuserland&emc=rss | 4 | 2 | [
54938
] | null | null | null | null | null | null | null | null | null | train |
|
54,909 | nextmoveone | 2007-09-15T14:21:16 | Quick Poll (programming preference) | Ruby on Rails or PHP?<p><p>-For Webservice Consumption<p>-Webservice Deployment<p>-Database Interaction<p>-Scaling <p><p>anybody? | 6 | 19 | [
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54,911 | amichail | 2007-09-15T14:32:45 | Theory Girl by the University of Washington CSE Band [mp3] | http://www.cs.washington.edu/orgs/student-affairs/cseband/studio/Theory%20Girl.mp3 | 6 | 2 | [
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54,913 | mitch | 2007-09-15T14:49:02 | Benoit's Diary Shows Wrestler Was Depressed - TvByDemand | Forums | WWE | null | http://www.tvbydemand.com/topic.asp?TOPIC_ID=833&FORUM_ID=49&CAT_ID=2&Topic_Title=Benoit%92s+Diary+Shows+Wrestler++Was+Depressed&Forum_Title=WWE | 1 | -1 | null | null | true | null | null | null | null | null | null | null | train |
54,915 | pg | 2007-09-15T14:50:30 | The Mosquito | http://www.swedishaerosport.se/joel_press.htm | 2 | 1 | [
59911
] | null | null | null | null | null | null | null | null | null | train |
|
54,917 | nickb | 2007-09-15T15:01:24 | How Bill Atkinson got the idea for the "marching ants" effect | null | http://folklore.org/StoryView.py?project=Macintosh&story=MacPaint_Evolution.txt | 8 | 1 | [
55118
] | null | null | null | null | null | null | null | null | null | train |
54,922 | mitch | 2007-09-15T15:39:39 | Another WWE has been released. | null | http://www.tvbydemand.com/topic.asp?TOPIC_ID=810&FORUM_ID=49&CAT_ID=2&Forum_Title=WWE&Topic_Title=Ric+Flair+has+quit | 1 | -1 | null | null | true | no_article | null | null | null | null | 2024-11-08T14:36:12 | null | train |
54,926 | donna | 2007-09-15T16:11:44 | Technology Design or Evolution? | http://www.technologyreview.com/read_article.aspx?id=17089&ch=infotech&a=f | 3 | 1 | [
54928
] | null | null | null | null | null | null | null | null | null | train |
|
54,932 | axiom | 2007-09-15T16:37:32 | Scientists to implant artificial cerebellum in robot | http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&RCN=28240 | 3 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
54,937 | Ultrapreneur | 2007-09-15T16:42:34 | When a meeting with a VC goes bad (Jobloft) | http://www.youtube.com/watch?v=vdbThklcD_8 | 33 | 20 | [
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|
54,942 | Ultrapreneur | 2007-09-15T16:54:46 | A success story (26 year old Michael Worry CEO Nuvation) | http://www.digitalmooselounge.com/press/press_3.htm | 1 | 0 | null | null | null | no_title | null | null | null | null | 2024-11-08T04:34:19 | null | train |
|
54,944 | nickb | 2007-09-15T16:57:32 | Why g ~ pi^2 | http://godplaysdice.blogspot.com/2007/09/why-g-2.html | 32 | 8 | [
55079,
54962,
54989
] | null | null | null | null | null | null | null | null | null | train |
|
54,945 | Ultrapreneur | 2007-09-15T17:07:13 | Hacker fuel (can't live without it) | Alright, so everyone know the life of an entrepreneur/hacker is a 24/7 gig and there are certain foods/drinks an entrepreneur can't live without.<p>What gets you through the long days... cold pizza? energy drinks? loud music? cheap noodles?<p>share your "can't live without" diet | null | 11 | 41 | [
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54,955 | mitch | 2007-09-15T17:54:41 | New Contest: Winners will be paid $25 (us) - TvByDemand | Forums | TvByDemand News and Events | null | http://www.tvbydemand.com/topic.asp?TOPIC_ID=837&FORUM_ID=48&CAT_ID=1&Topic_Title=New+Contest%3A+Winners+will+be+paid+%2425+%28us%29&Forum_Title=TvByDemand+News+and+Events | 1 | -1 | null | null | true | null | null | null | null | null | null | null | train |
54,970 | paul | 2007-09-15T18:47:49 | The bloodsucking worm that fights allergies from inside your tummy | null | http://www.dailymail.co.uk/pages/live/articles/technology/technology.html?in_article_id=481875&in_page_id=1965 | 3 | 1 | [
55069
] | null | null | null | null | null | null | null | null | null | train |
54,977 | rob | 2007-09-15T19:31:37 | Aaron Swartz's Jottit has been officially released | "Hi there. Sorry to bother you, but you asked me
to send you an email when Jottit was out for you
to take a look at. Well, after a lot of hard work
by my creators, Simon Carstensen and Aaron Swartz,
I'm happy to say that things are finally ready.<p>Take a look at<p><a href="http://jottit.com/" rel="nofollow">http://jottit.com/</a><p>and let me know what you think. (Just reply to
this email!)<p>Thanks so much,
- Jottit.com" | http://jottit.com/ | 51 | 88 | [
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54,978 | nickb | 2007-09-15T19:35:05 | Mises Blog: "There is nothing ethically or morally wrong with an ad-blocker." | null | http://blog.mises.org/archives/007149.asp | 12 | 7 | [
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54,979 | ericb | 2007-09-15T19:37:26 | Text Message Spam | Anyone else get this message too? Is an anti-spam solution likely to be implemented when the cell phone companies make money from the spam? The odd thing about this type of spam is it may have been more profitable for verizon than the spammer. | http://www.msnbc.msn.com/id/20593519/ | 2 | 2 | [
54982,
55292
] | null | null | no_title | null | null | null | null | 2024-11-07T23:20:34 | null | train |
54,995 | ziutek | 2007-09-15T20:23:21 | Warning: 10 online marketing trends to ignore | http://news.adversitement.nl/newsitems/index/category:4/newsitem:8 | 1 | 2 | [
55080,
55128
] | null | null | null | null | null | null | null | null | null | train |
|
54,997 | mcxx | 2007-09-15T20:27:10 | Marketing a small web business | http://www.webdesignfromscratch.com/marketing-a-small-web-design-business.cfm | 3 | 0 | null | null | null | null | null | null | null | null | null | null | train |
|
55,029 | sdsantos | 2007-09-15T21:39:28 | TwitterNotes - Take notes anywhere using Twitter | null | http://twitternotes.com/ | 3 | 1 | [
55093
] | null | null | no_article | null | null | null | null | 2024-11-08T21:33:27 | null | train |
55,035 | null | 2007-09-15T21:57:21 | null | null | null | null | null | null | [
"true"
] | null | null | null | null | null | null | null | null | train |
55,037 | null | 2007-09-15T21:58:36 | null | null | null | null | null | null | [
"true"
] | null | null | null | null | null | null | null | null | train |
55,062 | georgebabe | 2007-09-15T23:07:14 | Web Site Search - Goodbye Google Mini! Hello Google Custom Search | null | http://www.softwareprojects.com/resources/programming/t-site-search-goodbye-google-mini-hello-google-custom-search-1398.html | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
55,086 | ereldon | 2007-09-16T00:33:49 | Students buy into masters degrees | Question is: what do students actually learn by going to school for an extra couple years instead of learning the ropes in the real world? | http://www.nytimes.com/2007/09/12/education/12masters.html?ex=1347336000&en=d9d434ae25a45071&ei=5124&partner=facebook&exprod=facebook | 1 | -1 | null | null | true | null | null | null | null | null | null | null | train |
55,088 | DougBTX | 2007-09-16T00:54:05 | Parkinson's law | Parkinson's Law states that "work expands so as to fill the time available for its completion." | http://en.wikipedia.org/wiki/Parkinson%27s_Law | 2 | 0 | null | null | null | no_error | Parkinson's law | 2001-05-03T19:44:06Z | Contributors to Wikimedia projects |
From Wikipedia, the free encyclopedia
Parkinson's law can refer to either of two observations, published in 1955 by the naval historian C. Northcote Parkinson as an essay in The Economist:[1]
"work expands so as to fill the time available for its completion",
the number of workers within public administration, bureaucracy or officialdom tends to grow, regardless of the amount of work to be done. This was attributed mainly to two factors: that officials want subordinates, not rivals, and that officials make work for each other.
The first paragraph of the essay mentioned the first meaning above as a "commonplace observation", and the rest of the essay was devoted to the latter observation, terming it "Parkinson's Law".
The first-referenced meaning of the law – "Work expands to fill the available time" – has sprouted several corollaries, the best known being the Stock-Sanford corollary to Parkinson's law:
If you wait until the last minute, it only takes a minute to do.[2]
Other corollaries include Horstman's corollary to Parkinson's law, coined by Mark Horstman of website manager-tools.com:[3]
Work contracts to fit in the time we give it.[4]
the Asimov corollary to Parkinson's law:
In ten hours a day you have time to fall twice as far behind your commitments as in five hours a day.[5]
as well as corollaries relating to computers, such as:
Data expands to fill the space available for storage.[6]
The law can be generalized further as:
The demand upon a resource tends to expand to match the supply of the resource (If the price is zero).
An extension is often added:
The reverse is not true.
This generalization has come to resemble what some economists regard as the law of demand – namely, the lower the price of a service or commodity, the greater the quantity demanded. This is also referred to as induced demand.
This was the main focus of the essay by Cyril Northcote Parkinson, published in The Economist in 1955,[1][7] and reprinted with other similar essays in the successful 1958 book Parkinson's Law: The Pursuit of Progress.[8] The book was translated into many languages. It was highly popular in the Soviet Union and its sphere of influence.[9] In 1986, Alessandro Natta complained about the swelling bureaucracy in Italy. Mikhail Gorbachev responded that "Parkinson's law works everywhere."[10]
Parkinson derived the dictum from his extensive experience in the British Civil Service. He gave, as examples, the growth in the size of the British Admiralty and Colonial Office even though the numbers of their ships and colonies were declining.
Much of the essay is dedicated to a summary of purportedly scientific observations supporting the law, such as the increase in the number of employees at the Colonial Office while the British Empire declined (he showed that it had its greatest number of staff when it was folded into the Foreign Office due to a lack of colonies to administer). He explained this growth using two forces: (1) "An official wants to multiply subordinates, not rivals", and (2) "Officials make work for each other." He noted that the number employed in a bureaucracy rose by 5–7% per year "irrespective of any variation in the amount of work (if any) to be done".
Parkinson presented the growth as a mathematical equation describing the rate at which bureaucracies expand over time, with the formula , in which k was the number of officials wanting subordinates, m was the hours they spent writing minutes to each other.
Observing that the promotion of employees necessitated the hiring of subordinates, and that time used answering minutes requires more work; Parkinson states: "In any public administrative department not actually at war the staff increase may be expected to follow this formula" (for a given year) [1]
x – number of new employees to be hired annually
k – number of employees who want to be promoted by hiring new employees
m – number of working hours per person for the preparation of internal memoranda (micropolitics)
P – difference: age at hiring − age at retirement
n – number of administrative files actually completed
In a different essay included in the book, Parkinson proposed a rule about the efficiency of administrative councils. He defined a "coefficient of inefficiency" with the number of members as the main determining variable. This is a semi-humorous attempt to define the size at which a committee or other decision-making body becomes completely inefficient.
In Parkinson's Law: The Pursuit of Progress, London: John Murray, 1958 a chapter is devoted to the basic question of what he called comitology: how committees, government cabinets, and other such bodies are created and eventually grow irrelevant (or are initially designed as such). (The word comitology has recently been independently invented by the European Union for a different non-humorous meaning.)[11][12]
Empirical evidence is drawn from historical and contemporary government cabinets. Most often, the minimal size of a state's most powerful and prestigious body is five members. From English history, Parkinson notes a number of bodies that lost power as they grew:
The first cabinet was the Council of the Crown, now the House of Lords, which grew from an unknown number to 29, to 50 before 1600, by which time it had lost much of its power.
A new body was appointed in 1257, the "Lords of the King's Council", numbering fewer than 10. The body grew, and ceased to meet when it had 172 members.
The third incarnation was the Privy Council, initially also numbering fewer than 10 members, rising to 47 in 1679.
In 1715, the Privy Council lost power to the Cabinet Council with eight members, rising to 20 by 1725.
Around 1740, the Cabinet Council was superseded by an inner group, called the Cabinet, initially with five members. At the time of Parkinson's study (the 1950s), the Cabinet was still the official governing body. Parkinson observed that, from 1939 on, there was an effort to save the Cabinet as an institution. The membership had been fluctuating from a high of 23 members in 1939, down to 18 in 1954.
A detailed mathematical expression is proposed by Parkinson for the coefficient of inefficiency, featuring many possible influences. In 2008, an attempt was made to empirically verify the proposed model.[13] Parkinson's conjecture that membership exceeding a number "between 19.9 and 22.4" makes a committee manifestly inefficient seems well justified by the evidence proposed[citation needed]. Less certain is the optimal number of members, which must lie between three (a logical minimum) and 20. (Within a group of 20, individual discussions may occur, diluting the power of the leader.) That it may be eight seems arguable but is not supported by observation: no contemporary government in Parkinson's data set had eight members, and only king Charles I of England had a Committee of State of that size.
Dilbert principle
Gustafson's law
Hofstadter's law
Lewis–Mogridge position
Induced demand
Iron triangle
Jevons paradox
Law of triviality
List of eponymous laws
Peter principle
Planning fallacy
Reference class forecasting
SnackWell effect
Student syndrome
Time management
Zawinski's Law
^ a b c Parkinson, Cyril Northcote (19 November 1955). "Parkinson's Law". The Economist. London.
^ Pannett, Alan Shalini Sequeira; Dines, Andrew; Day, Andrew (2013). Key Skills for Professionals: How to Succeed in Professional Services. Kogan Page. p. 65. ISBN 978-0-7494-6877-4.
^ Alexander Clark; Bailey Sousa (12 March 2018). How to Be a Happy Academic: A Guide to Being Effective in Research, Writing. SAGE. ISBN 978-1-5264-4904-7.
^ Barber, Cam. "How to write a speech in 15 minutes". Vivid method. Retrieved 11 November 2014.
^ Isaac Asimov, in Nightfall and Other Stories, introductory material to "The Machine That Won the War"
^ Jansen, Peter (2008). IT-Service-Management Volgens ITIL. Derde Editie. Pearson Education. p. 179. ISBN 978-90-430-1323-9.
^ Fowler, Elizabeth M (5 May 1957). "It's a 'Law' now: Payrolls grow". The New York Times.
^ Parkinson, C. Northcote (1958). Parkinson's Law: The Pursuit of Progress (1st ed.). London: John Murray General Publishing Division. ISBN 978-0719510496.
^ Brown, Archie (2009). The Rise and Fall of Communism. New York: Ecco. p. 589. ISBN 978-0-06-113879-9.
^ O'Sullivan, John (June 2008). "Margaret Thatcher: A Legacy of Freedom". Imprimis. 37 (6). Hillsdale College: 6.
^ "comitology". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
^ A Brief List of Misused English Terms in EU Publications (PDF) (Report). 18 June 2013. Archived from the original (PDF) on 10 August 2013.
^ Klimek, Peter; Hanel, Rudolf; Thurner, Stefan (14 April 2008), "To how many politicians should government be left?", Physica A, 388 (18): 3939–3947, arXiv:0804.2202, Bibcode:2009PhyA..388.3939K, doi:10.1016/j.physa.2009.06.012, S2CID 12097887, It is often argued – as now e.g. in the discussion of the future size of the European Commission – that decision making bodies of a size beyond 20 become strongly inefficient. We report empirical evidence that the performance of national governments declines with increasing membership and undergoes a qualitative change in behavior at a particular group size. We use recent UNDP, World Bank and CIA data on overall government efficacy, i.e. stability, the quality of policy formulation as well as human development indices of individual countries and relate it to the country's cabinet size. We are able to understand our findings through a simple physical model of opinion dynamics in groups..
Parkinson, Cyril Northcote (1958). Parkinson's Law, or The Pursuit of Progress. London: John Murray.
Grunwald, Beverly (17 November 1968). "Mrs. Parkinson's Law". The New York Times Book Review. p. 5.
Planet Money Episode 877: "The Laws Of The Office", 21 November 2018, NPR
Parkinson, Cyril Northcote (19 November 1955), "Parkinson's Law", The Economist.
——— (November 1955), "Parkinson's Law" (PDF), The Economist, Berglas.
C. Northcote Parkinson, Parkinson's Law – extract (1958)
| 2024-11-07T22:32:51 | en | train |
55,097 | maurycy | 2007-09-16T01:30:55 | Bye, Bye B-School, or why even hedge fund managers no longer believe in MBA | http://www.nytimes.com/2007/09/16/business/16mba.html?ex=1347595200&en=b862d0447dec4711&ei=5090&partner=rssuserland&emc=rss | 20 | 17 | [
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55,132 | tojileon | 2007-09-16T03:25:09 | Mark Shuttleworth says how Ubuntu community was built. Advantage: Not in Silicon Valley | null | http://blogs.cnet.com/8301-13505_1-9779167-16.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
55,152 | cstejerean | 2007-09-16T04:53:51 | Web 2.0 Widgets for big businesses | http://venturebeat.com/2007/09/13/ibms-qedwiki-web-20-widgets-for-big-businesses/ | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
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55,155 | cstejerean | 2007-09-16T05:10:54 | Data Errors during drive communication | http://kerneltrap.org/Linux/Data_Errors_During_Drive_Communication | 2 | 0 | null | null | null | no_error | An Interview With Linus Torvalds: Linux and Git - Part 1 30 Years Of Linux | null | null | For Part Two, click here.
Thirty years ago, Linus Torvalds was a 21 year old student at the University of Helsinki when he first released the Linux Kernel. His announcement started, “I’m doing a (free) operating system (just a hobby, won't be big and professional…)”. Three decades later, the top 500 supercomputers are all running Linux, as are over 70% of all smartphones. Linux is clearly both big and professional.
For three decades, Linus Torvalds has led Linux Kernel development, inspiring countless other developers and open source projects. In 2005, Linus also created Git to help manage the kernel development process, and it has since become the most popular version control system, trusted by countless open source and proprietary projects.
The following interview continues our series with Open Source Leaders. Linus Torvalds replied to our questions via email, reflecting on what he's learned over the years from leading a large open source project. In this first part, we focus on Linux kernel development and Git. "[Linux] was a personal project that grew not out of some big dream to create a new operating system," Linus explains, "but literally grew kind of haphazardly from me initially just trying to learn the in-and-outs of my new PC hardware."
Regarding creating Git and then handing it off to Junio Hamano to improve and maintain, Linus noted, "I don't want to claim that programming is an art, because it really is mostly just about 'good engineering'. I'm a big believer in Thomas Edison's 'one percent inspiration and ninety-nine percent perspiration' mantra: it's almost all about the little details and the everyday grunt-work. But there is that occasional 'inspiration' part, that 'good taste' thing that is about more than just solving some problem - solving it cleanly and nicely and yes, even beautifully. And Junio had that 'good taste'."
Read on for the first in a two-part interview. Check back next week for the second part, where Linus explores the lessons and insights gained from three decades at the helm of the Linux kernel.
Translations: [Chinese], [Korean], [Vietnamese]: (Contact us if you'd like to translate this interview into another language.)
Linux Kernel Development
Jeremy Andrews: Linux is everywhere, and has been an inspiration to the entire open source world. Of course, it wasn't always that way. You famously released the Linux kernel back in 1991 with a modest Usenet posting on comp.os.minix. A decade later you wrote an engaging and personal book titled, "Just for Fun: The Story of an Accidental Revolutionary" exploring much of that history. This year, in August, Linux will celebrate its 30th anniversary! That's amazing, congratulations! At what point during this journey did you realize what you'd done, that Linux was so much more than "just a hobby"?
Linus Torvalds: This may sound a bit ridiculous, but that actually happened very early. Already by late '91 (and certainly by early '92) Linux had already become much bigger than I had expected.
And yeah, considering that by that point, there were probably just a few hundred users (and even "users" may be too strong - people were tinkering with it), it probably sounds odd considering how Linux then later ended up growing much bigger. But in many ways for me personally, the big inflection point was when I realized that other people are actually using it, and interested in it, and it started to have a life of its own. People started sending patches, and the system was actually starting to do much more than I had initially really envisioned.
I think that X11 was ported to Linux some time in April '92 (don't take my word for the dates - it's a loong time ago), and that was another big step where suddenly there was a GUI and a whole new set of capabilities.
To put this all in perspective - I really didn't start out with any big plans of high expectations. It was a personal project that grew not out of some big dream to create a new operating system, but literally grew kind of haphazardly from me initially just trying to learn the in-and-outs of my new PC hardware.
So when I released the very first version, it was really more of a "look at what I did", and sure, I was hoping that others would find it interesting, but it wasn't a real serious and usable OS. It was more of a proof of concept, and just a personal project I had worked on for several months at that time.
And going from that "personal project" to being something where others used it, sent feedback (and bug reports), and occasional patches, that was the big change for me.
Just to give an example of something really fundamental: the original copyright license was something like "you can distribute this in source form, but not for money".
That was because for me one of the issues had literally been that commercial unix was expensive (well, for a poor student who spent all his money on the new PC it was), and so to me a big important thing was that the source code be available (so that people could tinker with it), and I wanted it to be open to people like me who just couldn't afford the alternatives.
And I changed the license in late '91 (or maybe very early '92) to the GPLv2 because there were people who wanted to distribute it on floppies to local Unix Users Groups, but wanted to at least recoup the costs of the floppies and their copying time. And I realized that was obviously entirely reasonable, and that the important thing wasn't the "no money", but the "source needs to be openly available" part.
End result: not only did people distribute it at Unix user group meetings, but early floppy distributions like SLS and Slackware happened within months.
Compared to those initial really fundamental changes, everything else was "incremental". Sure, some of the incrementals were pretty big (IBM coming aboard, Oracle DB being ported, Red Hat IPOs, Android becoming big on phones etc), but they were still less personally revolutionary than that early initial "people I don't even know are using Linux''.
JA: Do you ever regret your choice of license, or how much money other people and companies have made off something you created?
LT: Absolutely not.
First off, I'm doing quite well. I'm not insanely rich, but I'm a well-paid software engineer, doing what I like to do, on my own schedule. I'm not hurting.
But equally importantly, I'm 100% convinced that the license has been a big part of the success of Linux (and Git, for that matter). I think everybody involved ends up being much happier when they know that everybody has equal rights, and nobody is special with regards to licensing.
There's a fair number of these "dual license" projects where the original owner retains a commercial license ("you can use this in your proprietary product if you pay us license fees") and then on the other hand the project is also available under something like the GPL for open source cases.
And I think it's really hard to build a community around that kind of situation, because the open source side always knows it's "second class". Plus it leads to a lot of just licensing paperwork in order for the special party to always retain their special rights. So it adds a lot of friction to the project.
And on the other hand, I've seen a lot of BSD (or MIT or similar) licensed open source projects that just fragment when they become big enough to be commercially important, and the involved companies inevitably decide to turn their own parts proprietary.
So I think the GPLv2 is pretty much the perfect balance of "everybody works under the same rules", and still requires that people give back to the community ("tit-for-tat"). And everybody knows that all the other people involved are bound by the same rules, so it's all very equitable and fair.
Of course, another part of that is that you also get out what you put in. Sure, you can try to "coast" on the project and be just a user, and that's ok. But if you do that, you also have no control over the project. That can be perfectly fine too, if you really just need a basic operating system, and Linux already does everything you want. But if you have special requirements, the only way to really affect the project is to participate.
This keeps everybody honest. Including me. Anybody can fork the project and go their own way, and say "bye bye Linus, I'm taking over maintenance of my version of Linux". I'm "special" only because - and as long as - people trust me to do a good job. And that's exactly how it should be.
That "anybody can maintain their own version" worried some people about the GPLv2, but I really think it's a strength, not a weakness. Somewhat unintuitively, I think it's actually what has caused Linux to avoid fragmenting: everybody can make their own fork of the project, and that's OK. In fact, that was one of the core design principles of "Git" - every clone of the repository is its own little fork, and people (and companies) forking off their own version is how all development really gets done.
So forking isn't a problem, as long as you can then merge back the good parts. And that's where the GPLv2 comes in. The right to fork and do your own thing is important, but the other side of the coin is equally important - the right to then always join back together when a fork was shown to be successful.
Another issue is that you really want to have the tools to support that workflow, but you also have to have the mindset to support it. A big impediment to joining forks back is not just licensing, but also "bad blood". If the fork starts from very antagonistic reasons, it can be very hard to merge the two forks - not for licensing or technical reasons, but because the fork was so acrimonious. Again, I think Linux has avoided that mainly because we've always seen forking things as natural, and then it's also very natural to try to merge back when some work has shown itself to be successful.
So this answer kind of went off at a tangent, but I think it's an important one - I very much don't regret the choice of license, because I really do think the GPLv2 is a huge part of why Linux has been successful.
Money really isn't that great of a motivator. It doesn't pull people together. Having a common project, and really feeling that you really can be a full partner in that project, that motivates people, I think.
JA: These days when people release source code under the GPLv2, they generally do it because of Linux. How did you find the license, and how much time and effort did you put into reviewing other existing licenses?
LT: Back then, people still had fairly big flame wars about BSD vs GPL (I think partly fueled by how rms really has a knack for pissing people off), so I'd seen some of the license discussions just through various usenet newsgroups I was reading (things like comp.arch, comp.os.minix etc).
But the two main reasons were probably simply gcc - which was very much instrumental in getting Linux going, since I absolutely required a C compiler - and Lars Wirzenius ("Lasu"), who was the other Swedish-speaking CS student at University in my year (Swedish being a fairly small minority in Finland).
Lasu was much more into license discussions etc than I was.
To me, the choice of GPLv2 wasn't some huge political issue, it was mainly about the fact that my original license had been so ad-hoc and needed updating, and I felt indebted to gcc, and the GPLv2 matched my "you have to give source back" expectations.
So rather than make up another license (or just edit the original one - just removing the "no money can change hands" clause could have been an option), I wanted to pick one that people already knew about, and had had some lawyers involved.
JA: What is your typical day like? How much of it is spent writing code, versus reviewing code, versus reading and writing emails? And how do you balance personal life and working on the Linux Kernel?
LT: I write very little code these days, and haven't for a long time. And when I do write code, the most common situation is that there's some discussion about some particular problem, and I make changes and send them out as a patch mainly as an explanation of a suggested solution.
In other words, most of the code I write is more of a "look, how about we do it this way" where the patch is a very concrete example. It's easy to get bogged down into some theoretical high-level discussion about how to solve something, and I find that the best way to describe a solution is often to just write the snippet of code - maybe not the whole thing - and just make it very concrete that way.
Because all my real work is spent on reading and writing emails. It's mostly about communication, not coding. In fact, I consider this kind of communication with journalists and tech bloggers etc to literally be part of my workday - it may get lower priority than actual technical discussions, but I do spend a fair amount of time on things like this too.
And yes, I spend time on code reviews too, but honestly, by the time I get a pull request, generally the code in question should already have been reviewed by multiple people already. So while I still look at patches, I actually tend to look more at the explanations, and the history of how the patch came to me. And with the people I've worked the longest with, I don't do even that: they are the maintainers of their subsystem, I'm not there to micro-manage their work.
So quite often, my main job is to "be there", and be the collection point, and be the person who manages and enforces the releases. In other words, my job is generally more about the maintenance process than the low-level code.
JA: What is your work environment like? For example, do you prefer a dark room with no distractions, or a room with a view? Do you tend to work in silence, or while listening to music? What kind of hardware do you typically use? Do you review code with vi in a terminal, or with a fancy IDE? And, do you have a preferred Linux distribution for this work?
LT: My room isn't exactly "dark", but I do have the blinds on the window next to my desk closed, because I don't want bright sunlight (not that it's necessarily very common this time of year in Oregon ;). So no views, just a (messy) desk, with dual 4k monitors and a powerful desktop computer under the desk. And a couple of laptops sitting around for testing and for when I'm on the road.
And I want to work in silence. I used to hate the ticking of mechanical disk drives - happily long relegated to the garbage bin as I've used exclusively SSD's for over a decade by now - and noisy CPU fans are unacceptable too.
And it's all done in a traditional terminal, although I don't use 'vi'. I use this abomination called "micro-emacs", which has absolutely nothing to do with GNU emacs except that some of the key bindings are similar. I got used to it at the University of Helsinki when I was a wee lad, and I've not been able to wean myself from it, although I suspect I will have to soon enough. I hacked up (a very limited) utf-8 support for it a few years ago, but it's really showing its age, and showing all the signs of having been written in the 80's and the version I use was a fork that hasn't been maintained since the mid 90's.
University of Helsinki used it because it worked on DOS, VAX/VMS and Unix, which is why I got introduced to it. And now my fingers are hardcoded for it. I really need to switch over to something that is actually maintained and does utf-8 properly. Probably 'nano'. But my hacked-up piece of historical garbage works just barely well enough that I've never been really forced to teach my old fingers new tricks.
So my desktop environment is fairly simple: several text terminals open, and a web browser with email (and several other tabs, mostly news and tech sites). I want to have a fair amount of desktop space, because I'm used to having fairly big terminal windows (100x40 is kind of my default starting size), and I have multiple terminals open side-by side. Thus the dual 4k monitors.
I use Fedora on all my machines, not because it's necessarily "preferred", but because it's what I'm used to. I don't care deeply about the distribution - to me it's mainly a way to get Linux installed on a machine and get all my tools set up, so that I can then replace the kernel and work on just that.
JA: The Linux Kernel Mailing List is where kernel development happens publicly, and is extremely high traffic. How do you keep up with so much email? Have you explored other solutions for collaboration and communication outside of a mailing list, or is there something about a simple mailing list that is perfect for what you do?
LT: Oh, I don't read the kernel mailing list directly, and haven't in years. It's much too much.
No, the point of the kernel mailing list is that it basically gets cc'd on all the discussions (well - one of the kernel mailing lists do, there are many - and then the traditional lkml list is the fallback for when there isn't some more targeted list). And that way, when a new person is brought into the discussion, they can see the history and the background by looking at the kernel mailing list.
So what I used to do was to be subscribed to the list, but have all the lkml email that I wasn't cc'd on personally be auto-archived, so I'd not see it by default. But then when some issue escalated to me, all that discussion would show up, because it was there in my email, just not in my inbox until it was needed.
These days, I actually use the lore.kernel.org functionality instead, because it works so well and we have some other tools built around it. So rather than having it auto-archived in my own mail archives, the discussions end up being visible that way instead. But the basic workflow is conceptually the same.
I do get a fair amount of email still, obviously - but in many ways it has been getting better over the years, rather than worse. A big part of that is Git and how well the kernel release flow works: we used to have many more problems with code flow, and tooling. My email situation was actually much much worse back around the turn of the century, when we still dealt in huge patch-bombs and we had serious scalability problems in the development flow.
And the mailing list (with tooling around it) model really does work very well. That's not to say that people don't use other means of communication in addition to email (both person-to-person, and the mailing lists): there are people who enjoy various realtime chat setups (IRC being the traditional one). And while that has never been my thing, it is clearly what some people like to use for brainstorming. But that "mailing list as an archive" model works very well, and works seamlessly together with the whole "send patches between developers as emails" and "send problem reports as emails".
So email remains the main communication channel, and makes it easy to discuss technical issues, with patches embedded in the same medium. And it works across time zones, which is very important when everybody is so spread out geographically.
JA: I followed kernel development closely for about a decade, blogging about it on KernelTrap and writing about new features as they evolved. I stopped around the time the 3.0 kernel was released, which had followed 8 years of 2.6.x versions. Is it possible to summarize some of the more interesting things that have happened in the kernel since the 3.0 release?
LT: Heh. That's so long ago that I couldn't even begin to summarize things. It's been a decade since 3.0, and we've had a lot of technical changes in that decade. ARM has grown up and ARM64 has become one of our primary architectures. Lots and lots of new drivers, and new core functionality.
If anything, what is interesting about the last decade is how we've actually kept the actual development model really smooth, and what hasn't changed.
We've gone through many different version number schemes over the decades, we've had different development models, but the 3.0 release was in fact the one that finalized the model we've used ever since. It kind of made official the whole "releases are time-based, version numbers are just numbers, and don't have any feature dependencies".
We'd started the whole time-based releases with a merge window in the 2.6.x days, so that part wasn't new. But 3.0 was when the last vestiges of "the number has meaning" were thrown overboard.
We'd had the random numbering scheme (mainly before 1.0), we'd had the whole "odd minor numbers means development kernel, even means stable production kernel" model, and then in 2.6.x we started doing the time-based release model. But people still had that "what will it take to increase the major number" question. And 3.0 made it official that even the major version number has no meaning, and that we'll just try to keep the numbers easy to deal with and not let them grow too big.
So for the last decade, we've made absolutely huge changes (Git makes it easy to show some statistics in numbers: about three quarters of a million commits by over 17 thousand people). But the development model itself has actually been quite smooth and stable.
And that really hasn't always been the case. The first two decades of kernel development were full of fairly painful development model changes. This last decade has been much more predictable release-wise.
JA: As of now, the latest release is 5.12-rc5. How standardized is the release process? For example, what sorts of changes go into an -rc1, versus an -rc2 and so on? And at what point do you decide a given release is ready to be officially released? What happens if you're wrong and a large regression is found after the final release, and how often does this happen? How has this process evolved over the years?
LT: So I alluded to this earlier: the process itself really is pretty standard, and has stayed so for the last decade. It went through several upheavals before that, but it's actually been almost like clock-work since 3.0 (and in fact a few years before that - the switch to Git in many ways was the beginning of the modern process, and it took a while before everybody got used to it).
So we've had this cadence of "two weeks of merge window" followed by roughly 6-8 weekly release candidates before final release for almost 15 years by now, I think.
And the rules have always been the same, although they haven't always been entirely strictly enforced: the merge window is for new code that is supposedly "tested and ready", and then the subsequent roughly two months are for fixes and to actually make sure all the problems are shaken out. Which doesn't always happen, and sometimes that supposedly "ready" code gets disabled or outright reverted before the release.
And then it repeats - so we have a release roughly every 10 weeks or so.
And the release criteria is me feeling confident enough, which obviously in turn is based on what kinds of problem reports are still coming in. If some area still shows issues late in the rc game, I'm fairly aggressive about just reverting things, and saying "we'll deal with this in a later release once we've figured the thing out fully", but on the whole it's fairly rare that that is needed.
Does it always work out? No. Once the kernel is released - and particularly once a distro picks it up - you get new users, you get people who didn't test it during development that find things that didn't work and we didn't catch during the rc series. That's pretty much inevitable. It's part of why we have the whole "stable kernel" trees, which continue to add fixes after the release. And some stable kernels are maintained for longer than others, and get called LTS ("Long Term Support") kernels.
All of this has remained fairly unchanged in the last ten years, although we do end up having a lot more automation in place. Kernel testing automation is hard in general - partly because so much of the kernel is drivers which then obviously depends on hardware availability - but there are several farms doing both boot and performance testing, and do various randomized load testing. And that has improved a lot over the years.
JA: Last November you were quoted as being impressed by Apple's new ARM64 chips found in some of their new computers. Are you following the development effort to support them with Linux? I see work was merged into for-next. Is it likely Linux will boot on Apple's MacBook hardware as early as the upcoming 5.13 kernel? Are you likely to be an early adopter? What is the significance of ARM64?
LT: I'm checking in on it very occasionally, but it's early days yet. As you note, the very early support will likely be merged into 5.13, but you need to realize that that is really only the beginning, and doesn't make Apple hardware useful with Linux yet.
It's not the arm64 part that ends up being the problem, but all the drivers for the hardware around it (the SSD and GPU in particular). The early work so far gets some of the really low-level stuff working, but doesn't result in anything useful outside of early hardware enablement. It will take some time for it to be a real option for people to try out.
But it's not just the Apple hardware that has improved - the infrastructure for arm64 in general has grown up a lot, and the cores have gone from "Meh" to being much more competitive in the server space. The arm64 server space was pretty sad not that long ago, but Amazon's Graviton2 and Ampere's Altra processors - both based on the much improved ARM Neoverse IP - are much better than what the offerings were a few years ago.
I've been waiting to have a usable ARM machine for over a decade by now, and it's not there yet, but it's clearly much closer than it used to be.
In fact, I guess I could say that I've been wanting an ARM machine for much longer than that - back when I was a teenager, the machine I really wanted was an Acorn Archimedes, but availability and price made me go with a Sinclair QL (M68008 processor) and then obviously a few years later a i386 PC instead.
So it's been kind of brewing for decades, but they still haven't been widely available and price/performance competitive as computers for me. One day. Hopefully in the not too distant future.
JA: Is there anything in the kernel which is not optimal, but would require a complete rewrite to address properly? In other words, the kernel is 30 years old and knowledge, languages and hardware have changed a lot in these 30 years: if you rewrote it from scratch now, what would you change?
LT: We've actually been really good about even completely rewriting things if necessary, so anything that would have been an unmitigated disaster has long since been rewritten.
Sure, we have a fair amount of "compatibility" layers, but they are usually not horrendous. And it's unclear if even those compatibility layers would really go away if rewriting from scratch - they are about backwards compatibility with older binaries (and often backwards compatibility with older architectures, e.g. running 32-bit x86 apps on x86-64). Since I consider backwards compatibility to be very important, I'd want to keep those even in a rewrite.
So there are obviously lots of things that are "not optimal" in the sense that anything can be improved, but the way you phrase the question, I'd have to say that no, there's nothing there that I despise. There's legacy drivers that nobody is ever going to care about enough to clean up, and so they may do ugly things, but a key part of that is "nobody cares enough". It hasn't been a problem, and when it does become a problem we tend to fairly actively remove true legacy support that we can't find anybody that cares about. So we've gotten rid of lots of drivers over the years, and we've gotten rid of whole architecture support when it no longer makes any sense at all to maintain.
No, the only major reason for a "rewrite" would be if you end up having some use-case where the whole structure no longer makes sense. The most likely scenario would be some small embedded system that just doesn't want everything that Linux offers, and has a hardware footprint so small that it simply wants something smaller and simpler than what Linux has become over the years.
Because Linux has grown a lot. Even small hardware (think cell phones etc) today is much more capable than the original machine Linux was developed on was.
JA: What about rewriting at least parts with Rust, a language that was specifically designed for performance and safety? Is there room for improvement in this way? Do you feel it’s ever possible for another language like Rust to replace C in the kernel?
LT: We'll see. I don't think Rust will take over the core kernel, but doing individual drivers (and maybe whole driver subsystems) in it doesn't sound entirely unlikely. Maybe filesystems too. So it's not "replace C", but more of "augment our C code where it makes sense".
Of course, drivers in particular is about half of the actual kernel code, so there's a lot of room for that, but I don't think anybody is really expecting to rewrite existing drivers in Rust wholesale, more of a "some people will do new drivers in Rust, and a couple of drivers might be rewritten where it makes sense".
But right now that's more of a "people are trying it out and playing with it" rather than anything more than that. It's easy to point to advantages, but there are certainly complexities too, so I'm very much taking a wait-and-see approach to see if the promised advantages really do pan out.
JA: Are there any specific parts of the kernel that you are personally most proud of?
LT: The stand-out parts I tend to point to are the VFS ("virtual filesystem") layer (and the pathname lookup in particular) and our VM code. The former because Linux just does some of those fundamental things (looking up a filename really is such a core operation in an operating system) so much better than anything else out there. And the latter mainly because we support 20+ architectures, and we still do it with a largely unified VM layer, which I think is pretty impressive.
But at the same time, this is very much a function of "what part of the kernel do you care about". The kernel is big enough that different developers (and different users) will simply have different opinions of what matters most. Some people think scheduling is the most exciting part of the kernel. Others like the nitty-gritty of device drivers (and we have a lot of those). I personally tend to be more involved in the VM and VFS areas, so I then naturally point to those.
JA: I found this description of pathname lookup, and it's more complex than I expected. What makes the Linux implementation so much better than what is done in other operating systems? And what do you mean by "better"?
LT: Pathname lookup is really such a common and fundamental thing that most people outside of kernel developers don't even think about it as a problem: they just open files, and take it all for granted.
But it's actually fairly complicated to do really well. Exactly because absolutely everything does pathname lookups all the time, it's hugely performance-critical, and it's very much one of those areas where you also want to scale well in SMP environments, and it has lots of complexity in locking. And you very much do not want to do any IO, so caching is very important. In fact, pathname lookup is so important that you can't leave it to the low-level filesystem, because we have 20+ different filesystems, and having each of them do their own caching and their own locking would be a complete disaster.
So one of the main things the VFS layer does is really handle all the locking and caching of pathname components, and handle all the serialization and the mount point traversal, and do it all with mostly lock-free algorithms (RCU), but also with some really clever lock-like things (the Linux kernel "lockref" lock is a very special "spinlock with reference count" which was literally designed for the dcache caching, and it's basically a specialized lock-aware reference count that can do lock elision for certain common situations).
End result: the low-level file systems still need to do the actual lookup for things that aren't cached, but they don't need to worry about caching and all the coherency rules and the atomicity rules that go along with pathname lookups. The VFS handles all that for them.
And it all outperforms anything any other operating system has done, while basically scaling perfectly to even machines with thousands of CPU's. And it does that even when those machines all end up touching the same directories (because things like the root directory, or a project home directory, are things that even heavily threaded applications all touch at the same time, and that don't get distributed to any kind of per-thread behavior).
So it's not just "better", it's "Better" with a capital 'B'. Nothing else out there comes even close. The Linux dcache is simply in a class all its own.
JA: The past year has been difficult all around the world. How has the COVID-19 pandemic affected the kernel development process?
LT: It actually has had very minimal effect, because of how we always worked. Email really ends up being a wonderful tool, and we didn't rely on face-to-face meetings.
Yes, it did affect the yearly kernel summit last year (and this year is still up in the air), and most conferences got cancelled or turned virtual. And people who worked in offices before mostly started working from home (but a lot of the core kernel maintainers already did so). So a lot of things around it changed, but the core development itself worked exactly as before.
And it obviously affected all our lives in other ways - just the social ramifications in general. But on the whole, being a kernel developer who already interacted with people almost entirely over email, we were probably some of the least affected.
Git Distributed Version Control System
JA: Linux is only one of your ubiquitous contributions to open source. In 2005 you also created Git, the extremely popular distributed source control system. You quickly migrated the Linux kernel source tree out of the proprietary Bitkeeper and into the newly created and open sourced Git, and in the same year handed off maintainership to Junio Hamano. There's a lot of fascinating history there, what led you to handing off leadership on this project so quickly, and how did you find and select Junio?
LT: So there's two parts to this answer.
The first part is that I very much did not want to create a new source control system. Linux was created because I find the low-level interface between hardware and software fascinating - it's basically a labor of love and personal interest. In contrast, Git was created out of necessity: not because I found source control interesting, but because I absolutely despised most source control systems out there, and the one that I found most palatable and had really worked fairly well in the Linux development model (BitKeeper) had become untenable.
End result: I've been doing Linux over 30 years (the anniversary of the first release is still a few months away, but I had started on what would become Linux already 30 years ago), and I've been maintaining it the whole time. But Git? I did not ever think I'd really want to maintain it long-term. I love using it, and I obviously think it's the best SCM out there by a huge amount, but it's not my fundamental passion and interest, if you see what I'm trying to say.
So I always wanted somebody else to maintain the SCM for me - in fact I would have been happiest had I not had to write one in the first place.
That's kind of the background.
As to Junio - he was actually one of the very first people who came in as Git developers. His first change came in within days after I had made the very first (and very rough) version of Git public. So Junio has actually been around some since pretty much the beginning of Git.
But it's not like I handed the project off to the first random person to show up. I did maintain Git for a few months, and the thing that made me ask Junio if he wanted to be the maintainer is that very-hard-to-describe notion of "good taste". I don't really have a better description for it: programming is about solving technical problems, but how you solve them, and how you think about them is important too, and it's one of those things you start to recognize over time: certain people have that "good taste" thing and pick the "right" solution.
I don't want to claim that programming is an art, because it really is mostly just about "good engineering". I'm a big believer in Thomas Edison's "one percent inspiration and ninety-nine percent perspiration" mantra: it's almost all about the little details and the everyday grunt-work. But there is that occasional "inspiration" part, that "good taste" thing that is about more than just solving some problem - solving it cleanly and nicely and yes, even beautifully.
And Junio had that "good taste".
And every time Git comes up, I try to remember to really make it very very clear: I may have started and designed the core ideas in Git, but I often get too much credit for that part. It's been 15+ years, and I was really only involved with Git in that first year. Junio has been an exemplary maintainer, and he's the one who has made Git what it is today.
Btw, this whole "good taste" thing and finding people who have it, and trusting them - that's very much not just about Git. It's very much the history of Linux too. Unlike Git, Linux is obviously a project that I still do actively maintain, but very much like Git, it's also a project with lots of other people involved, and I think one of the big successes of Linux is having literally hundreds of maintainers around, all with that hard-to-define "good taste", and all people who maintain parts of the kernel.
JA: Have you ever given control to a maintainer only to later determine it was the wrong decision?
LT: Our maintainership structure has never been so black-and-white and inflexible that that would ever have been an issue. In fact, it's not like we even make maintainership control be something very documented: we do have a MAINTAINERS file, but that's so that you can find the right people, it's not really a sign of some exclusive ownership.
So the whole "who owns what" is more of a fluid guideline, and a "this person is active and is doing a good job" than some "oops, now we gave that person ownership and then he screwed up".
And it's fluid also in the sense that maybe you are the maintainer of one subsystem, but if there's something you then need from another subsystem, you can often cross borders. Usually it's something that people talk about extensively before doing, of course, but the point is that it does happen and it's not some hard "you're only supposed to touch that file" kind of rule.
In fact, this is actually somewhat related to the earlier discussion about the licensing, and another example of how one of the design principles of "Git" was that whole "everybody has their own tree, and no tree is technically special".
Because a lot of other projects have used tooling - like CVS or SVN - that fundamentally does make some people special, and that fundamentally does have a "ownership" that goes along with it. In the BSD world, they call it the "commit bit": giving a maintainer the "commit bit" means that he's now allowed to commit to the central repository (or at least parts of it).
I always detested that model, because it inevitably results in politics and the "clique" model of development, where some people are special and implicitly trusted. And the problem isn't even the "implicitly trusted" part - it's really that the other side of the coin is that other people are not trusted, and are by definition outsiders, and have to go through one of the guardians.
Again, in Git that kind of situation doesn't exist. Everybody is equal. Anybody can do a clone, do their own development, and if they do a good job they can get merged back (and if they do an outstanding job, they become maintainers, and they end up being the ones doing the merging into their trees ;).
So there's no need to give people special privileges - no need for that "commit bit". And that also means that you avoid the politics around it, and you don't need to trust people implicitly. If they end up doing a bad job - or more commonly, just end up fading away and finding another interest - they don't get merged back, and they also don't stand in the way of other people who have fresh new ideas.
JA: Do new features of Git ever impress you, and become part of your workflow? Are there features you'd still like to see added?
LT: My use cases were obviously the first ones to be fulfilled, so for me it has seldom been about new features.
Over the years, Git has certainly improved, and some of it has been noticeable in my workflow too. For example, Git has always been fairly fast - it was one of my design goals, after all - but a lot of it was originally done as shell-script around some core helper programs. Over the years, most of that shell scripting has gone away, and it means that I can apply patch-bombs from Andrew Morton even faster than I could originally. Which is very gratifying, as that was actually one of the early benchmarks I used for performance testing.
So Git has always been good for me, but it's gotten better.
The big improvements have been about how much better it has become to use as a "regular user". A lot of that has been people learning the Git workflow and just getting used to it (it is very different from CVS and other things that people used to be used to), but a lot of it is Git itself having become a lot more pleasant to use.
Conclusion, Part One
In the second part of this interview, Linus talks about what he's learned from managing a large open source project. He offers much insight and advice to maintainers about what he's found works best for him, and how he avoids burn out. He also talks about the Linux Foundation, and what he does when he's not focused on developing the Linux kernel.
For Part Two, click here
Click the link to see what other Open Source Leaders talk with Tag1 about. | 2024-11-07T23:27:27 | en | train |
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55,161 | cstejerean | 2007-09-16T05:32:34 | The bicycle powered supercomputer | http://www.engadget.com/2007/09/15/the-bicycle-powered-supercomputer/ | 2 | 0 | null | null | null | null | null | null | null | null | null | null | train |
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55,164 | redrory | 2007-09-16T05:48:39 | lol: Look at me trying to learn Ruby on Rails... | Things are coming along well, Starting my first app, 2nite<p>Just waiting for InstantRail to finish UnZipping..<p>Come back for updates.. | http://redrory.com/2007/09/15/lol-look-at-me-trying-to-learn-ruby-on-rails/ | 2 | 1 | [
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Please forward this error screen to redrory.com's WebMaster.
The server cannot find the requested page:
| 2024-11-08T16:25:22 | null | train |
55,172 | cstejerean | 2007-09-16T06:33:31 | The Entrepreneurial Mind: Managing with Assumptions | null | http://forum.belmont.edu/cornwall/archives/007830.html | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
55,175 | cstejerean | 2007-09-16T06:38:07 | Yahoo Mash: The Social Network for Graffiti Lovers | null | http://bits.blogs.nytimes.com/2007/09/15/yahoo-mash-attempts-hip/ | 1 | 0 | null | null | null | null | null | null | null | null | null | null | train |
55,196 | tojileon | 2007-09-16T07:20:11 | Have you seen this PG page? | http://www.paulgraham.com/gateway.html | 33 | 21 | [
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