[Sugar-devel] Sugar-devel Digest, Vol 11, Issue 89 (SoaS performance/hard drive swapping)

[Douglas McClendon]

Bill Bogstad wrote:
> On Wed, Sep 16, 2009 at 10:51 AM, Jim Simmons <nicestep at gmail.com> wrote:
>> Art,
>>
>> Being a frugal person I do all my home computing on legacy machines
>> like the ones you've tested with.  As far as SoaS is concerned, I
>> agree with your conclusions.  I got better results than you did with
>> my Pentium III because I've installed a USB 2.0 expansion card on it.
>> I haven't tried a Pentium II.
>>
>> What I'd like to point out is that while these older machines don't
>> run SoaS very well they may be perfectly adequate running Fedora 11
>> with the included Sugar environment, especially if the Sugar
>> environment and its Activities are the only things running.  I do that
>> with a Pentium III with 256 Meg of RAM and probably much less than 1
>> gigahertz speed.  One advantage you have doing this is you can have a
>> swap partition on the hard drive.  Another advantage is that the
>> Fedora 11 distribution probably supports more sound cards than SoaS
>> ever could.  Plus you don't have to deal with slow USB 1.0 ports,
>> flaky thumb drives, etc.
> 
> I was under the impression that SoaS WAS Fedora 11 at that level of
> the software (just installed and configured a little differently). I
> haven't delved into SoaS packages in detail so I could be wrong here.
> 
> As for swap, if you are repurposing discarded machines on any kind of
> scale you are going to end up with non-functional machines which are a
> great source of parts.  Strip the RAM from the dead machines and
> upgrade the rest.  This is something that even 10-12 year old kids can
> help with and probably enjoy.  If it's part of a project where they
> get to take the machines home afterwards they will be even more
> motivated.
> 
> My wish is to figure out ways that SoaS can take advantage of the hard
> drive while still remaining a portable environment. Hmm...  Hey,  here
> is a potentially useful 'hack'.  Have SoaS detect the presence of a
> hard drive at boot time, look for partitions marked as Linux swap, and
> enable swapping on them.  This could make 256Meg machines much more
> usable.  Should be as safe as the contents of partitions with the
> Linux swap type are pretty much fair game to be overwritten at any
> reboot.
> 
> The only case that I can think of where this would be a problem is if
> someone is doing Linux kernel dumps to swap space for diagnostic
> purposes.  If they are doing this then they are uber-Linux wizards and
> are already having to deal with this potential issue in their normal
> usage of the machine.
> 
> Anybody want to code/script this up?

I'm pretty sure /etc/rc.d/init.d/livesys (search for swapon) in f11/soas
already does just that.

> 
> Or we could make a swap file on the flash stick (not in the Linux root
> filesystem though, too many levels of indirection for good
> performance).  This could be setup to only be turned on when the
> physical memory in the machine is below a certain amount.

With the wide variance in performance of usb drives (from rotating, to
good flash, to old cheap slow flash), I think you might need more logic
to get a good general purpose solution here.  I.e. there may be cases 
where the flash performance is so bad it isn't worth doing.

-dmc



> 
> Perhaps do both in the same system startup script.  Check for hard
> drive swap partition(s) first and use if available.  If no hard drive
> swap partitions are available, check memory of machine and use a swap
> file on flash if memory is low.  This idea
> I really like (of course I'm biased).
> 
> Bill Bogstad
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