Memory leaks

[ɹəuəllıʍ ʇɐb]

Memory leaks explained: http://en.wikipedia.org/wiki/Memory_leak

There have been mention of memory leaks in several threads recently, especially related to Firefox. I thought I should go into this in a few sentences. The above Wikipedia article explains it pretty good in details.

As a system software developer I know the causes and effects of "memory leaks" pretty well. It is basically memory allocated by an application, then never released (until the application ends). If this is done repeatedly in long running applications, this can show a tremendous amount of allocated memory building up over time (and it shows in the Task Manager).

However, this is not necessarily a totally bad thing, as unused memory is usually paged out to the virtual memory file, so it does not clog up the RAM. So the main effect may only be that the application will take some time to clean up the virtual memory as it terminates.

I think Firefox is especially afflicted with that malaise not because of bad programming, but most probably by the extensions and plug-ins. I will do some testing later with a plain Firefox (safe mode), and see if it uses the same amount of memory over time as FF running with all installed extensions.

All applications, by the way, are bound to have some memory leaks over time - including Internet Explorer. Sometimes because of programming bugs, sometimes intentional to keep certain information readily available, and sometimes it is simply unavoidable - e.g. when a subfunction unexpectedly crashes, but leaving the main application alive.

[-pops-]

Thanks for that, Pat. Very interesting and useful information there :)

[andsome]

I got lost. Not that technically minded where computers are concerned. Is this a long term building up problem, or is it all put right when we close down and start up again? That's all I really need to know.

[-pops-]

I think we're OK, andsome.

Regular shutting down (as we both do, I think) should keep us well un-leaked :)

[dadyassa]

I got lost. Not that technically minded where computers are concerned. Is this a long term building up problem, or is it all put right when we close down and start up again? That's all I really need to know.

Having a sneaky try of firefox eh ? ;) ;) :lol:

[andsome]

I think we're OK, andsome.

Regular shutting down (as we both do, I think) should keep us well un-leaked :)

Thanks.

I got lost. Not that technically minded where computers are concerned. Is this a long term building up problem, or is it all put right when we close down and start up again? That's all I really need to know.

Having a sneaky try of firefox eh ? ;) ;) :lol:

Tried ages ago and uninstalled.

[catgate]

I would imagine that there are those on here who, after sitting at the keyboard for a long period, will themseves be in need of a leak.

[CurlyWhirly]

Very interesting read Pat, thanks :)

It affects me as I use Firefox and am VERY happy with it.

[ɹəuəllıʍ ʇɐb]

I got lost. Not that technically minded where computers are concerned. Is this a long term building up problem, or is it all put right when we close down and start up again? That's all I really need to know.

Memory allocations are done by applications as a request to the OS. This memory slot is recorded as belonging to the requesting application. If an application closes or crashes without explicitly releasing that memory, the OS will do it when the application terminates.

So all memory that has been requested by an application will be freed when it ends. There is no need to reboot Windows to reclaim leaked memory. Except, of course, for Windows itself - there are so many Windows processes and services that may also leak that we really need to reboot once in a while. I reboot Windows about once or twice a week.

[andsome]

I got lost. Not that technically minded where computers are concerned. Is this a long term building up problem, or is it all put right when we close down and start up again? That's all I really need to know.

Memory allocations are done by applications as a request to the OS. This memory slot is recorded as belonging to the requesting application. If an application closes or crashes without explicitly releasing that memory, the OS will do it when the application terminates.

So all memory that has been requested by an application will be freed when it ends. There is no need to reboot Windows to reclaim leaked memory. Except, of course, for Windows itself - there are so many Windows processes and services that may also leak that we really need to reboot once in a while. I reboot Windows about once or twice a week.

When you say that you reboot Windows once or twice a week, do you mean that you leave the machine running 24/7. I close down every night and reboot every morning, unless asked to reboot more often after an install.

[ɹəuəllıʍ ʇɐb]

Yes, my computers run constantly, for several reasons. One is that my spam filter on Outlook only works when Outlook is running. Another is that I run BOINC with ClimatePrediction, which would never finish a workunit in time if I shut down the system overnight. There is no harm in running a desktop PC or server 24/7. (I do shut down laptop computers when not in use).