Can I load BIOS-defaults from harddrive by empty battery?

[tchouch]

Does anyone know how to load BIOS-defaults after CMOS-battery is empty (without user actions like F1 etc. - PC should work without keyboard)? PC and battery are of course OK at time, the problem is - PC should boot everytime after battery is dead... I think, it is possible to save BIOS values on disk and by each boot load a couple drivers to write in CMOS from harddrive? May be does anyone know any old solution for MS DOS?

 

[MKuiper]

tchouch,

I think what you want is not possible because the bios starts complaining before the os is loaded. Your only change might be a customized bios.
Marcel

 

[mingis]

Are the BIOS settings not reset to default values after battery is dead? I thought that one of possibilities to reset default values is to take out the battery?

 

[tchouch]

Thanks for Your interest.
The BIOS-Settings may be of course reset to defaults, but an user needs to press F2, and then may be F1 (if first boot device is by default drive A and the PC should boot from drive C, for example). The problem is, PC does not have any keyboard and it will waiting for F1, but it can never be pressed. I think now, it may be better, easy to change BIOS - defaults to do not ask for user input (F1, F2 etc.) and easy try to boot from C-drive, if checksum is wrong (it is the problem with empty battery!). But I don't know any application/sample to read (at least!) and may be change BIOS settings (I will then of course make a new ROM with this new BIOS).

 

[mingis]

1. Ok, Floppy is the first boot drive, but harddrive is the second. If there is no floppy inside, system should boot from the harddisk. Or system does not recognise any harddisk by default?
2. Are you sure, that BIOS waits for F1 because of checksum failure but not because of absence of the keyboard? Plug in some broken keyboard or only keyboard chip without any keys and keyboard housing.
3. Buy new battery.

 

[tchouch]

mingis, thanks.
1. System does recognise the harddisk by default, but it is so: without battery system write
Press F1 to Setup
Press F2 to load defaults.
If I press F2, system says somewhat like this:
Can't read disk in drive A!
Press F1 to skip.
2. Yes I'm sure. Such messages comes with keyboard present too. It is not a problem to find a keyboard - I have enough of them. The problem is: PC works in long-life systems (10-20 and may be more years), which have no keyboards at all, and if battery is empty, client can't start and use these systems still all batteries are replaced. I can't insert an accu instead - system may be not used 3-5 month.

 

[mingis]

Boot from the floppy, restore your saved CMOS contents using out 70h and out 71h, reboot the system from harddisk. Or your sophisticated device has no floppy as well?

 

[tchouch]

Thanks for 70h and 71h, I will use it.
Normally it has no floppy too. If it has any, it may have not a boot-disk inserted.

 

[mingis]

> it may have not a boot-disk inserted
You can use two floppy drives then - A: and B:, A: - always with the boot floppy inserted, B: - for user purposes. Btw, 70 and 71 are processor ports used to read/write CMOS contents.