17 Jun
2006
17 Jun
'06
9:32 p.m.
From: Fred Cisin <cisin at xenosoft.com>
Reply-To: "General Discussion: On-Topic and Off-Topic
Posts"<cctalk at classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Floppy stepping problem
Date: Sat, 17 Jun 2006 13:54:22 -0700 (PDT)
Hi Fred
I had issues getting the 1.44M to work at all with the wire from the
360K disk connected. I've removed the wire from the 360K disk. The
360K seems to work fine when staying in the DOS world. I'm able to
transfer files to and from the 1.44M to the 360K. It is only when I use
my program that it gets lost.
>The 360K floppy I have, only has the drive
select jumpers. I've tried
>changing the DBT and using Int 13 but it is still not working. I guess
>I'll just have to live with it. It is working, it is just that when the
>1.44M goes>to another track, I have to recal the 360K drive...
On Sat, 17 Jun 2006, Chuck Guzis wrote:
Does your 360K drive have the terminator
installed? If not, have you
tried
it with the terminator? (you don't need to
use the standard 150 ohm
ones;
1K should be good enough).
Check pin 34 of the drive. Is it using it for "Disk Change", or for
"READY"?
Use Int 1Eh to point to a new parameter table, copied from the old one.
Insert some code to check whether 1E is still pointing to your table after
a floppy access.
Insert some code to check the validity of your table after a floppy access.
Point 1E back to where it was, afterwards.
According to what I've seen, one also needs to do INT 13 with AH=0
to get these values transfered to the controller.
Check the behavior under DOS 2.10 (which has the absolutely slowest
default step rates (to work with the Qume 142))
What else can be narrowed down as occurring when you get the recals?
(several other kinds of floppy errors could result in a recal.)
I'd do another post with psudo code to show what I do.
Can you assume that everyone will have 640K?
You COULD read the image into RAM, to avoid any switching of floppies.
I've thought about that but the way I'm generating my program assume
to run in a 64K memory chunk. I do have a few that I know don't have a
full 640K. I'd like to stay within what I can do in a *.COM file.
I'm currently doing a full track.
Dwight