Formatting and verifying MFM hard disks

From: Marvin Johnston <marvin_at_rain.org>
Date: Sun Nov 30 01:41:03 2003

Something in the back of my mind says that "g c800:5" won't work but
"g=c800:5" does the job. IIRC, when I first started to use debug to LLF
the HDs, I wasted a lot of time trying to figure out why things weren't
working when using the "g c800:5" command.

Fred Cisin wrote:
>
> > >Well, lets see.... if your on a PC, I think if you type at the DOS prompt
> > >c:\> debug c800
> > That's assuming that the controller card is set to the standard address
> > of C800. C800 is the default for PCs but the cards can be addresses to
> > different addresses. Checkit is handy for finding the card address. Also
> > the code doesn't usually start right at the biginning of the ROM. It starts
> > at an offset of 5 in most controllers so you'd use debug then "g c800:5".
> > I've seen a couple of controllers that started at 2 and I think I remember
> > one that started at 10.
>
> NO!
> <pedantic>
> C800 is NOT the address! It is the SEGMENT component of a two part
> address. But when used as STATED: g C800 , it would NOT cause a branch to
> C800:0 as intended! Instead, it would go to OFFSET C800 of the current
> segment! xxxx:C800
>
> If you want offset 0 of segment C800, then the command must be: g C800:0
> NOT g C800 !!!!!!!!!!
>
> g C800:5 would, indeed, be correct for an offset of 5 within segment C800
>
> BUT "g C800" is NOT going to work.
> </pedantic>
Received on Sun Nov 30 2003 - 01:41:03 GMT