[comp.sys.att] INT 19H in AT&T 6300 ROM BIOS

wtm@neoucom.UUCP (01/30/87)

Hi,

I wanted to write a little program that would simulate depressing
the ctrl-alt-del key sequence, as I am working on a 6300 remotely
via modem.  I have some memory resident programs that don't give
you the option of unloading, so I'd like to have a batch file that
resets my mahcine.

My machine has resident diagnostics v 1.21 that I'm running this
on, so I'd be interested in hearing if 1.43 will get rid of the
following problem.

Here's what I did:

I used DEBUG to enter the following program, which I've used on
IBMs and several other compatibles.  It seems to ALWAYS work for
rebooting from the floppy, and on some 6300's it always works.  On
some 6300s, it'll work about 1/2 the time for the the fixed disk.
It appears to me from the 6300 tech manual that the BIOS doesn't
give the HDU enough time to reset ("only" three tries), and thus
the system hangs.  By the way the system with v 1.43 always would
boot the HDU correctly.

Here's my klutzy attempt.  Feed it sans comments to DEBUG to try
it out:

Cut this and put it in a file, then DEBUG < file to create
WARMBOOT.COM.

N WARMBOOT.COM		;new file name
A 100			;standard load point
INT 19			;system reset
MOV AH,4C		;dos function request
MOV AL,0		;exit with no error set
INT 21			;exit to dos
R CX			;cx contains length of file to write
8			;write 8 bytes
W			;write them
Q			;exit debug

Does anybody have a better idea as how to do this?  Thanks in
advance for any who comment.

  --Bill

Bill Mayhew
Division of Basic Medical Sciences
Northeastern Ohio Universites' College of Medicine
Rootston, OH  44272  USA    phone:  216-325-2511
(wtm@neoucom.UUCP    ...!cbatt!neoucom!wtm)

davidsen@steinmetz.UUCP (02/03/87)

In article <372@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes:
> ... stuff about reboot ...
>Does anybody have a better idea as how to do this?  Thanks in
>advance for any who comment.

I'm not sure it *better*, but a hardware reset of a 8086 or 8088
is followed by execution at FFFF:0000. On *many* machines a
program which does a far jump to that location will give the
effect of a power-on boot, which clears some problems which a
DOS boot doesn't. There may be hardware which needs to be reset,
so try this before you form an opinion.


-- 
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