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Old 10-26-2003, 12:05 PM   #1
whaase
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2 questions!


1) I used to be able to use the 'mail' command. It's gone, how can I get it back?

2) I used 'top' to get some info and I noticed that almost all my memory was used up. I have 655 megs and 621 or so was used. When I run 'gkrellm' it tells me I have 500 or so megs free. Why the difference and which one is correct?

Walter
 
Old 10-26-2003, 12:19 PM   #2
ToniT
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1) The mailx package contains the program in question.
2) I don't know about grellm, but the number the top shows contais also the memory used to disk cache (that is, some files (or parts of files) are kept in memory so that they can be accessed faster. In case some program needs more memoy, some of these caches are thrown away.)
 
Old 10-26-2003, 12:25 PM   #3
whaase
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Quote:
Originally posted by ToniT
1) The mailx package contains the program in question.

Got it, thank you!


2) I don't know about grellm, but the number the top shows contais also the memory used to disk cache (that is, some files (or parts of files) are kept in memory so that they can be accessed faster. In case some program needs more memoy, some of these caches are thrown away.)
Hmmm, I'll look at it more carefully... seems like quite a difference.. but I'll look

Walter
 
Old 10-26-2003, 03:04 PM   #4
Joey.Dale
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Linux handles memory differntly than winblows, you bought 655 and linux trys to use it all, you could have 4GB of RAM and Linux will use it all.
 
Old 10-26-2003, 03:22 PM   #5
Robert0380
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Quote:
Originally posted by Joey.Dale
you bought 655 and linux trys to use it all, you could have 4GB of RAM and Linux will use it all.
this is a good thing by the way.
 
Old 10-26-2003, 04:03 PM   #6
bulliver
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Quote:
2) I used 'top' to get some info and I noticed that almost all my memory was used up. I have 655 megs and 621 or so was used. When I run 'gkrellm' it tells me I have 500 or so megs free. Why the difference and which one is correct?
Here is the output of 'free -h' on by box:
Code:
             total       used       free     shared    buffers     cached
Mem:           757        721         36          0        132        352
-/+ buffers/cache:        236        520
Swap:          486         16        469
And gkrellm says:
Code:
757M - 225M used
So where does the discrepancy come in? You need to keep in mind that Linux caches all data that you access and open in RAM for faster access later. After a day or so of having your box up and running free will report almost all of your RAM as being used. If this RAM is needed for application data however, some of the cache will be purged and The RAM reclaimed as needed. This is a Good Thing.

What you need to look at is the '-/+ buffers/cache:' line. Here you can see that only 236M of application data memory is being used, and that I actually have 520M of RAM free to be used.

gkrellm's report subtracts the buffer/cache for you automatically, so that's where the discrepancy comes from. Also: gkrellm says 225M used, and free says 236 used. This is because free is just a snapshot of the current use whereas gkrellm updates itself on the fly, and I got these two figures about 30 seconds apart. Both free and gkrellm just gleam this info from the /proc filesystem (ie: direct from the kernel).

Last edited by bulliver; 10-26-2003 at 04:09 PM.
 
Old 10-26-2003, 05:36 PM   #7
ranger12002
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when i had mandrake i was only using 78mb of ram and i had 256 how come i didnt use as much?
 
Old 10-27-2003, 12:13 AM   #8
bulliver
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Well, you can only cache things that you have already loaded into memory right? So it would seem thast you opened less than 78M of data before rebooting....

You need to be fairly active with your machine to fill up your cache...ie watching lots of mpgs, listening to lots of mp3s or oggs, etc. Just running a web server is not usually going to do it...

I have 768M of RAM, and it takes a day or two of heavy use before my cache is full.
 
Old 10-27-2003, 11:38 AM   #9
Starchild
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For example; try starting OpenOffice Writer twice.
for me:
first time: 30 s
second time : 2-3 s
 
  


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