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    SubjectRe: [PATCH] ramdisk for unusable memory > 960MB / > 2 GB
    On Mon, 1 Feb 1999, Manfred Spraul wrote:

    >This patch adds:
    >- 2 new kernel functions (alloc_hugemem, free_hugemem) that manage
    >physical, unmapped memory. (Note: if you have 1 GB memory, then there is
    >usually 64 MB unused memory).
    >- a special ramdisk that uses this memory. ( MAJOR=126, MINOR=0..7)

    The idea is nice, but the help is fuzzy:

    >+Hugeram Ramdisk
    >+CONFIG_BLK_DEV_HUGERAMD
    >+ Saying Y here makes it possible to use the memory above 1 gigabyte
    >+ as a ramdisk. This only works if you have enabled CONFIG_HUGEMEM.

    >+Huge memory support
    >+CONFIG_HUGEMEM
    >+ Enables kernel support for more than 2 gigabyte physical memory.
    >+ Note that this memory is only used for special devices such as
    >+ hugeramd.
    >+
    >+ If unsure, say 'N'.
    >+

    What about this:

    ----------------------------------------------------------------
    Huge memory support
    CONFIG_HUGEMEM
    Enables kernel support for really huge amounts of RAM (beyond 1 Gigabyte)

    Linux currently supports up to almost 1 Gigabyte of RAM (960MB to be exact)
    on Intel and compatibles computers.
    If this is too little for you, there are two things you can do:

    1: Increase manually the limit to 1984MB.
    Read the note in include/linux/page.h to do this.
    2: Use the RAM above the 960MB limit (or above 1984MB if you applied 1:)
    as a special ramdisk.

    Saying Y here makes it possible to use the solution 2:
    use the RAM above the limit as a ramdisk.

    Note that to actually enable this ramdisk, you must also say Y to the
    "Huge Ramdisk support" below.

    ----------------------------------------------------------------

    Huge Ramdisk support
    CONFIG_BLK_DEV_HUGERAMD
    Saying Y here makes it possible to use the memory above 1 Gigabyte
    as a ramdisk. This only works if you have enabled "Huge Memory support".

    The ramdisk can be accessed through block special files
    /dev/hugeram0 ... /dev/hugeram7, with major number 126 and
    minor numbers 0..7 (do "man mknod" for help how to create them)

    ----------------------------------------------------------------


    Also, the note in linux/include/asm-i386/page.h was fixed
    (0x7000000 -> 0x80000000) in 2.2.1 so everything should be fine.


    Massimiliano Ghilardi

    ----------------------------------------------------------------
    | I have yet to meet a person who had a bad experience of Linux. |
    | Most have never had an experience. |
    ----------------------------------------------------------------



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