How to make my alarm as stable as a server? I have HTC Desire with original Android 2.2 (kernel 2.6.32.15-gf5a401c) with HTC Sence. I have not installed any task killers.

Now I have a stock alarm clock application.

Yesterday evening I set my alarm for 6:30am, but got up at 10 being 2h+ late for my work.
When I took my phone, I noticed 3 things


it was showing a message like "Adobe Flash Player cannot be installed without internet connection";
second thing I noted is "Low on space" notification --- common problem for HTC Desire;
my alarm was silently asking me if I want to snooze or dismiss it.


I want


to have an alarm clock on my phone as stable as my bicycle, i.e. which


works as expected;
does not turn off automatically after 1, 5, 10 or 100500 minutes;
does not stop working in case of update or any other event (except airplane mode);

to have Android update like Debian Squeeze, i.e. not to update automatically (at least if it causes problems), but gently suggest to install only security critical updates and to give any other suggestions only by special request;
some logging for my alarm to "debug" problems with waking up.


In the list above I mention not only the alarm, but the whole system (Android update), because I think that tuning off the system can help to stabilize my alarm. Correct me if I'm wrong.

Question


What can be done to make my system and, importantly, my alarm, very stable?
What is the most stable alarm clock app?
Is there any way to make it even more stable (for instance, turn off updates to stick with a stable version)?


What is done

I have found the following relevant threads:


"Is there an alarm clock event log?" has no satisfactory answer;
"Which Alarm clock app do you use to wake up in the morning?" suggests Smart Alarm Clock and Gentle Alarm, a similar thread suggests Alarm Clock Xtreme (ad-supported or paid ($2)); I do not have any information on stability of these;
the following threads about alarm clock incidents: [1], [2];
"disable update notification" - done.


Future

Probably at some point I will reinstall Android with a question of solving low internal memory problem in mind. So if there are some solutions for a different version of Android (say 2.3) or advice for installation to make my system and alarm stable I would like to know them.

Update
As roxan pointed out, probably alarm rings just for a few minutes. If it is so, I would like to turn off this feature or set this time to something big (2 hours or more).
I also use Desire and this has never/ever happened to me under any circumstances. Alarm would not work if you had killed it but you have clearly specified you don't have any task killer.

As you said there is Snooze/Dismiss screen, the alarm indeed went on. Are you sure you didn't miss when the alarm rang at the correct time? Or are you sure the volume is loud enough?