topic Re: Memory ... many terms in Operating System - HP-UX

Memory ... many terms

Manuales — Wed, 07 Dec 2005 18:21:22 GMT

Hi ... could you help me explaining me the ooutput ps command in memory line:

Memory: 589368K (176648K) real, 944360K (245876K) virtual, 1541748K free Page#
1/24

i can't understand very well about memory,
what is real memory?
what is virtual memory?
what is free memory?
what is phisical memory?

Thanks, Manuales

Re: Memory ... many terms

Sanjay_6 — Wed, 07 Dec 2005 18:30:59 GMT

Hi,

Maybe this will help,

http://docs.hp.com/en/1218/mem_mgt.html

Hope this helps.

Regds

Re: Memory ... many terms

Manuales — Wed, 07 Dec 2005 18:48:55 GMT

thanks sanjay .. i'm going to read it , but, could you tell me in little words please??

Thanks, Manuales.

Re: Memory ... many terms

Mel Burslan — Wed, 07 Dec 2005 21:11:42 GMT

to put it roughly,

real memory and physical memory usually refer to the same thing in most technical context which is the amount of actual RAM (hardware) found in a server.

virtual memory, for almost all intents and purposes, can be equated to the available swap space.

free memory is quite tricky as I have seen in the past that meant more than one thing. But in the global sense, you can look at your total memory amount as the total of RAM & SWAP. The operating system will occupy some of this total system memory, as well as any launched program will also use/reserve a chunk to itself, making the free memory go away. After all have been said and done, amount of free space left over, is referred to as free memory.

But take all of this with a big grain of salt as many people and many applications define these terms as the author of a document understands and they can be some variation of these definitions. So, be forewarned. To understnad the concept of memory better, you need to read a detailed document like Sanjay referred to about memory management on HPUX.

Hope this helps.