[Wolves] Progress report!!

[Mo Awkati]

Hi James

Thanks for the info it has shed the light on some
questions. You are right, the application do start
much much quicker once loaded.

I am still getting used to Linux but I have to say I
am very impressed with it. It can do everything I want
and more.

Thanks for your help

Mo







 --- James Turner <james at turnersoft.co.uk> wrote: > On
Thursday 08 Jan 2004 8:07 pm, David Goodwin
> wrote:
> > > Hi
> > >
> > > I used "free" on the command line to check on
> memory
> > > usage and about half of the 512MB is used uP????
> and
> > > that was straight from booting up to the desktop
> with
> > > no applications activated. Which command or
> > > application can I use to check on which
> processes are
> > > taking the memory and how do I free up some
> more??
> >
> > In terms of computers, the slowest thing is
> accessing data on a disk.
> > Because of this, Linux attempts to cache as much
> data you've read from the
> > disk as possible - so should you access the same
> file again, no disk reads
> > are required, and performance is stellar. Try
> running Open Office, or
> > Mozilla, once.... closing them down and then
> starting them up again -
> > you'll find the second time will be a *lot*
> quicker - this is because the
> > data is still held in memory, and all that was
> required as a bit of cpu
> > work.
> 
> Here's some typical output from the "free" command:
> 
>              total       used       free     shared 
>   buffers     cached
> Mem:        514544     510120       4424          0 
>     26136     285460
> -/+ buffers/cache:     198524     316020
> Swap:      2332004     102220    2229784
> 
> The figures on the top line show that almost all of
> the memory (512Mb) is 
> being made use of (the kernel always keeps a small
> portion free for some 
> reason that I forget at the moment). About 300Mb is
> used for buffers/cache 
> (holding information that is on disc in memory to
> speed things up if it's 
> needed - as described above), while the remainder is
> actually being used by 
> processes (or the kernel).
> 
> The second line of output shows what the memory
> usage would be if the 
> buffers/cache are subtracted from the "used" figure
> and added to the "free" 
> figure. Typically upto about 60% of RAM is always
> used for buffers/cache 
> (though this can be tuned using the /proc filesystem
> for specialist 
> performance requirements).
> 
> The third line shows the amount of swap space (or
> "virtual memory") in use, 
> which is stored on hard disc and is significantly
> slower than RAM (probably 
> several hundred times slower on modern machines).
> The amount of swap used and 
> the swap used compared to total memory are probably
> the best indicators of 
> memory shortage or plenty. Memory shortage (eg swap
> space = memory used, or 
> more) is characterised by frequent and noticable
> delays in performing tasks, 
> accompanied by the hard disc light coming on,
> indicating that the swap space 
> is being accessed.
> 
> On a newly rebooted machine, the "free mem" figure
> starts out high, then 
> decreases to a small value as information is read
> from disc and kept in case 
> it's needed again. This small amount of free memory
> remains fairly constant, 
> though it may sometime increase temporarily (eg just
> after quitting an 
> application or a user logging out). Sooner or later,
> the freed-up memory will 
> either be re-used by programs or the kernel or
> absorbed into buffers/cache.
> The "mem used excluding buffers/cache" figure may
> increase or decrease 
> depending on the requirements of any programs that
> are running, usually upto 
> a maximum of about 40% (unless you've changed the
> setting in /proc), 
> following which swap space starts to be used.
> 
> (hope there aren't too many mistakes in this!)
> 
> James
> 
> 
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