LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 03-18-2010, 03:12 PM   #1
karlochacon
Member
 
Registered: Dec 2006
Posts: 107

Rep: Reputation: 17
Memory Size doubt


hi

I have some Red Hat Ent 5.0 Servers which have 4GB of RAM
2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:21 EST 2007 i686 i686 i386

Code:
[root@~]# dmidecode | grep Size
        Runtime Size: 57104 bytes
        ROM Size: 4096 kB
        Installed Size: 32 KB
        Maximum Size: 32 KB
        Installed Size: 12288 KB
        Maximum Size: 12288 KB
        Size: 2048 MB
        Size: 2048 MB
but when I run top it shows
Code:
Mem:   3369744k total,  3126036k used,   243708k free,
same thing when I run
Code:
# free -m
            total       used       free     shared    buffers     cached
Mem:        3290       3052        237          0        359       1905

any idea why is not reporting the 4 GB?

thanks a lot
 
Old 03-18-2010, 03:15 PM   #2
karlochacon
Member
 
Registered: Dec 2006
Posts: 107

Original Poster
Rep: Reputation: 17
is this why is not reporting the 4GB? or something else?
http://www.cyberciti.biz/tips/redhat...m-support.html
 
Old 03-18-2010, 07:43 PM   #3
jamescondron
Member
 
Registered: Jul 2007
Location: Scunthorpe, UK
Distribution: Ubuntu 8.10; Gentoo; Debian Lenny
Posts: 961

Rep: Reputation: 69
What happens if you install the package?
 
Old 03-18-2010, 07:55 PM   #4
chrism01
LQ Guru
 
Registered: Aug 2004
Location: Sydney
Distribution: Centos 6.8, Centos 5.10
Posts: 17,240

Rep: Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324
Fundamentally, the system reserves some mem for the kernel+drivers, see eg http://kbase.redhat.com/faq/docs/DOC-6571, http://kbase.redhat.com/faq/docs/DOC-7064. Have a search http://www.redhat.com/search .
 
Old 03-18-2010, 08:31 PM   #5
Quakeboy02
Senior Member
 
Registered: Nov 2006
Distribution: Debian Squeeze 2.6.32.9 SMP AMD64
Posts: 3,275

Rep: Reputation: 126Reputation: 126
Quote:
Originally Posted by karlochacon View Post
is this why is not reporting the 4GB? or something else?
http://www.cyberciti.biz/tips/redhat...m-support.html
More than likely, at least that's the usual issue.
 
Old 03-19-2010, 03:59 AM   #6
nodopro
Member
 
Registered: Oct 2008
Posts: 48

Rep: Reputation: 16
Well actually it's 4GB. When you dmidecode will list each slot (bank). In your case, it list 2 banks that having 2GB memory each and you grep 'size' that's why it show size two times. To add it up, you have 4GB total (2 DIMMS and 2GB each).
 
Old 03-19-2010, 08:27 AM   #7
johnsfine
LQ Guru
 
Registered: Dec 2007
Distribution: Centos
Posts: 5,286

Rep: Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181Reputation: 1181
Quote:
Originally Posted by karlochacon View Post
is this why is not reporting the 4GB? or something else?
http://www.cyberciti.biz/tips/redhat...m-support.html
The topic of that link (install the PAE kernel) is almost certainly what you need.

But in that link there is some very careless phrasing

The non-PAE kernel can only address up to 4GB of memory. Install the kernel-PAE package if your machine has more than 4GB of memory

That part is misleading (and contradicted by other phrases on the same page).

The correct information is:

The non-PAE kernel can address up to 4GB of physical address space. 4GB of physical address space can contain only 3 and a fraction GB of actual memory (the exact amount is determined by the BIOS, not by Linux).

Install the kernel-PAE package if your machine has more than the 3 and a fraction GB of memory that fits in 4GB of physical address space.

Last edited by johnsfine; 03-19-2010 at 09:54 AM.
 
Old 03-19-2010, 09:46 AM   #8
i92guboj
Gentoo support team
 
Registered: May 2008
Location: Lucena, Córdoba (Spain)
Distribution: Gentoo
Posts: 4,063

Rep: Reputation: 381Reputation: 381Reputation: 381Reputation: 381
To sum up. you need a PAE-enabled kernel *or* a 64 bits OS, in case your cpu supports x86_64 at all.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
tool to detect number of memory slots, memory module type, speed, and size stefanwolf Linux - Hardware 8 04-22-2013 10:48 AM
Good Memory Size and Moemory Size in lsconf output Jaimine AIX 3 05-18-2009 02:07 PM
Doubt with shared memory (IPC). webquinty Linux - Newbie 0 11-05-2008 11:51 AM
is shared memory expandable in memory size? Thinking Programming 4 08-16-2005 10:57 AM
Doubt about how a linker builds a memory image funkymunky Programming 4 02-18-2005 12:59 PM


All times are GMT -5. The time now is 08:30 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration