Re: about /proc/meminfo and mmap

From: Cefiar (cefiar1@optushome.com.au)
Date: Sat Oct 21 2000 - 03:50:47 EDT

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    At 08:24 PM 20/10/00 -0400, Zhixu Liu wrote:
    >My PC have 128M RAM, but in /proc/meminfo, it display 122424K, not
    >128*1024K = 131072K, what does this mean?

    Sounds like something is stealing your ram.

    Usual suspects are..

    Shadow RAM is enabled.
      - This steals a TINY (usually 64k for BIOS, and 32k each for each extra
    memory address enabled) of ram. Nothing major though.

    Local memory accessing devices.
      - Embedded video cards (and possibly embedded sound devices) on boards
    using the Intel 815E chipset (and others) use local RAM for memory, instead
    of their own special memory - to reduce cost. Apart from weird memory
    sizes, this also can lead to latency and slow-down issues when accessing
    the memory normally. Many of these machines have AGP slots, and almost
    always have a PCI slot, so throwing in a cheap video (audio?) card can
    remove such issues, and frees up that memory again. Maximum I've seen a
    board allow for local video ram is 8 Meg, which is pretty much the amount
    you are missing. The board in question was a Socket 7 board with embedded
    video.

    --
      -=[ Stuart Young (Aka Cefiar) ]=-------------------------------
      | http://amarok.glasswings.com.au/ | cefiar1@optushome.com.au |
      ---------------------------------------------------------------
    

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