Professional Web Applications Themes

storing some bytes in CMOS-RAM - UNIX Programming

Hi, I would like to store a few bytes using the /dev/nvram device. Is there some free usable memory? And how to determine, which bytes are available? Or does the BIOS use the entire nvram-space? Thanks in advance, Juergen...

  1. #1

    Default storing some bytes in CMOS-RAM

    Hi,
    I would like to store a few bytes using the /dev/nvram device. Is there some
    free usable memory? And how to determine, which bytes are available? Or
    does the BIOS use the entire nvram-space?

    Thanks in advance,
    Juergen
    Jürgen Guest

  2. #2

    Default Re: storing some bytes in CMOS-RAM

    Jürgen Querengässer wrote: 

    The answer is specific to the flavor of system you are using. For many
    *NIX systems there is no such device. I suggest you ask in a forum
    that is specific to the system you are talking about.

    -- ced

    --
    Chuck Dillon
    Senior Software Engineer
    NimbleGen Systems Inc.

    Chuck Guest

  3. #3

    Default Re: storing some bytes in CMOS-RAM

    On Wed, 27 Aug 2003 13:29:07 +0200
    Jürgen Querengässer <de> wrote:
     

    From Configure.help in the Linux kernel source tree:

    /dev/nvram support
    CONFIG_NVRAM
    If you say Y here and create a character special file /dev/nvram
    with major number 10 and minor number 144 using mknod ("man mknod"),
    you get read and write access to the extra bytes of non-volatile
    memory in the real time clock (RTC), which is contained in every PC
    and most Ataris. The actual number of bytes varies, depending on the
    nvram in the system, but is usually 114 (128-14 for the RTC).

    This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
    on Ataris. /dev/nvram may be used to view settings there, or to
    change them (with some utility). It could also be used to frequently
    save a few bits of very important data that may not be lost over
    power-off and for which writing to disk is too insecure. Note
    however that most NVRAM space in a PC belongs to the BIOS and you
    should NEVER idly tamper with it. See Ralf Brown's interrupt list
    for a guide to the use of CMOS bytes by your BIOS.

    <end quote>

    I get the idea it's not something that you'd want to use if you could
    avoid it.

    Jason Creighton
    Jason Guest

Similar Threads

  1. bytes.pm problem
    By Sergei Shelukhin in forum PERL Modules
    Replies: 2
    Last Post: July 19th, 06:55 AM
  2. not getting bytes loaded
    By Frank Grimes in forum Macromedia Flash Actionscript
    Replies: 0
    Last Post: February 16th, 06:17 PM
  3. Bytes
    By Ron in forum Web Design
    Replies: 3
    Last Post: January 18th, 09:41 PM
  4. Replies: 14
    Last Post: September 22nd, 11:54 AM
  5. CMOS and log in problem
    By Chris Jones in forum Windows Setup, Administration & Security
    Replies: 0
    Last Post: July 11th, 02:28 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139