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using Ubuntu 12.04 with 2 Gb DDR3 ram with 3.2.0-39-generic

free -k
         total       used       free     shared    buffers     cached
Mem:       2012040    1875968     136072          0       4100     299696
-/+ buffers/cache:    1572172     439868
Swap:      2057212     260152    1797060

2 GB in KB:2097152

2097152-2012040=85112

Memory used by Kernel

dmesg|grep Memory

Memory: 1994460k/2058272k available (6571k kernel code, 452k absent, 63360k reserved, 6632k data, 920k init)

85112-77015=8097k

Where can i see this 8 Mb of used ram.If its used by Devices through DMA can it be visible.

Also is reserved refers to memory reserved for BIOS?

http://pastebin.com/GrvrfzUu

[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
[    0.000000]  BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 000000007da08c00 (usable)
[    0.000000]  BIOS-e820: 000000007da08c00 - 000000007da5cc00 (ACPI NVS)
[    0.000000]  BIOS-e820: 000000007da5cc00 - 000000007da5ec00 (ACPI data)
[    0.000000]  BIOS-e820: 000000007da5ec00 - 0000000080000000 (reserved)
[    0.000000]  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fed00400 (reserved)
[    0.000000]  BIOS-e820: 00000000fed20000 - 00000000feda0000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved)
[    0.000000]  BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
[    0.000000] NX (Execute Disable) protection: active
[    0.000000] SMBIOS 2.5 present.
[    0.000000] DMI: Dell Inc. OptiPlex 380                 /0F0TGN, BIOS A05 02/24/2011
[    0.000000] e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved)
[    0.000000] e820 remove range: 00000000000a0000 - 0000000000100000 (usable)
share|improve this question
    
... ... ...what?! –  Bobby Jul 11 '13 at 10:14
    
....what what?! –  kevin Jul 11 '13 at 10:15
    
I don't understand what you're asking for. –  Bobby Jul 11 '13 at 10:16
    
Can we see memory used by devices through DMA? –  kevin Jul 11 '13 at 10:21
    
You should provide the full output of free and dmesg | grep Memory. There's no point in doing the arithmetic yourself when it's included in the standard output. –  user235731 Jul 11 '13 at 10:24

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