BIOS settings.

QNX Newsgroups (Archives) qdn.public.qnx4
1

Does anyone know of a QNX utility that can save and then restore the BIOS’s
CMOS memory (i.e., so I could have emergency diskette which would restore
the BIOS settings)? Has anyone ever written a beast like this?

2

Hi Lloyd,
I’ve written such beast few years ago, but in DOS environment :wink: It’s not a big deal to write your
own utility. Use 8bits port 0x70 to write there the address of register and read/write the value
throught the 8bits port 0x71. Use exactly 8 bits IO operations because these adresses are shared
with another stuff in modern PC. Also remember the first adresses (registers 0-0x0d) are for RTC’s
status/control and time|calendar, so don’t use these registers. 0x0e, 0x0f is shutdown status and
POST diagnostic bytes, avoid them also. Usually CMOS registers for BIOS settings are from 0x10 to
0x3f, but many RTC chips support addresses till 0x7f or more.
Best regards.

Eduard.
ed1k at ukr dot net

Lloyd Elwood <LloydE@harding.ca> wrote in article <aacdh1$20o$1@inn.qnx.com>…

Does anyone know of a QNX utility that can save and then restore the BIOS’s
CMOS memory (i.e., so I could have emergency diskette which would restore
the BIOS settings)? Has anyone ever written a beast like this?

3

Ooops, sorry. I re-read carefully your questions :wink: What do you mean by “restore the BIOS
settings”? Be very careful, if you lost your BIOS settings and reboot system - highly probably you
wont get booting :wink:

Eduard.
ed1k at ukr dot net

4

ed1k <ed1k@spamerstrap.com> wrote in article 01c1ef6c$05dc13a0$106fa8c0@ED1K…

Hi Lloyd,
I’ve written such beast few years ago, but in DOS environment > :wink: > It’s not a big deal to write
your
own utility. Use 8bits port 0x70 to write there the address of register and read/write the value
throught the 8bits port 0x71. Use exactly 8 bits IO operations because these adresses are shared
with another stuff in modern PC.

Bit 7 of port 0x70 controls the NMI logic on Intel PIIX4.

Also remember the first adresses (registers 0-0x0d) are for RTC’s
status/control and time|calendar, so don’t use these registers. 0x0e, 0x0f is shutdown status and
POST diagnostic bytes, avoid them also. Usually CMOS registers for BIOS settings are from 0x10 to
0x3f, but many RTC chips support addresses till 0x7f or more.

Intel PIIX4 chipset supports 2 banks:

  1. primary CMOS registers 0x0-0x7f through ports 0x70, 0x71;
  2. extended CMOS (can be disabled) registers 0x0-0x7f through ports 0x72, 0x73.
    –
    Eduard.
    ed1k at ukr dot net