[Malvern] Memory Reliability

[Matthew Wild]

Hi Guy...

On 8/14/07, Guy Inchbald <guy at steelpillow.com> wrote:
>
> On Tue, 14 Aug 2007 08:22:22, Geoff Bagley <geoff.bagley at btinternet.com>
> wrote:
> >Am I missing something here ?  Does the type of network you use have a
> >bearing on the potential
> >for memory leakage ?  Possibly in badly written network software ?
>
> Methinks ye networky topic, complete with dire jokes (hooray!), hath
> hijacked a perfectly good memory-related thread.


Agreed :)

Meanwhile, On Mon, 13 Aug 2007 00:31:09, Matthew Wild <mwild1 at gmail.com>
> wrote:
> >Memory is always freed when the process exits.
> and
> >Actually restarting the process should free the RAM,
>
> Indeed it should. When it doesn't, we call the phenomenon "memory leak".
> I guess you weren't around during the early days of Java?


I don't know what you mean exactly. If a process exits, it can no longer own
memory, or in fact any resources...

Memory leaks are when a process allocates memory, that is, it asks the OS
for a chunk of memory, a particular size. Due to bad code, it is possible
that this chunk gets forgotten about after it has been used, and the program
doesn't tell the OS to free it. Imagine this part of the code is run every
time a particular thing happens - say, a file is opened. Eventually the
number of used chunks will grow, and grow, and grow.

If, however, you quit this program, the OS will immediately know that it has
finished with these chunks of memory. They are then marked as FREE for any
other application on the system to use.

As you see, there is no need here for a reboot.

>There is not too much that an OS can do
> >about temporary files. Unless they are in a pre-allocated place that
> >gets cleaned at startup, a reboot will have no effect on these.
>
> Not too much maybe, but don't forget that Microsoft are real
> professionals: if it's possible and its crap, they'll fine a way.
> Windows' biggest temporary file (hey, I've forgotten which one, it's so
> long since I had to play with it)


You mean the swap file?  Also note that Linux uses seperate partitions for
swap, instead of re-using the *file* system that is for, er.. files...

does start in a pre-allocated place -
> which used to be bang in the middle of the system install area of the
> HD. When the allocated disc space filled up, the next bit of the file
> got stuck wherever the FAT 32 or NTFS filesystem felt like - and so on,
> building up a labyrinthine tangle of disc sectors for the ever-growing
> temp file - until the FAT got too - uh, fat, and the whole thing
> crashed. Luckily, as you say, the original empty file is recreated on
> rebooting.
>
>
> >I think you know more about openMosix than I do :)
>
> Only what I read in the FAQ you linked to.  ;)


I linked to nothing... I think you got me confused with someone else :)

>I find Inkscape a great application for vector graphics.
>
> Inkscape is coming along nicely, but is a bit limited in file formats
> ATM. I'm looking forward to Xara Xtreme reaching v1.0.


SVG rules! :)

>I am also able
> >to double-click .exe files in Ubuntu for WINE to run them (and I have
> >used this with setup exe's too).
>
> So, you can just download some install.exe, double-click it and WINE
> kicks in? I knew that was mooted but I didn't realise it was now
> working. Or does it still need a few magic spells in the usual Linux
> "it's so easy" kind of way?



I was as surprised when I found this out too. But yes, double-clicking an
exe runs it. Setup.exe, or any other kind. No magic required. I'm not sure I
even like this :)

Matthew.
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