DSQD Drives (Was: RE: Diags/Boot image for Altos 580)

From: Doc <doc_at_mdrconsult.com>
Date: Sun Mar 17 18:20:38 2002

On Sun, 17 Mar 2002, Fred Cisin (XenoSoft) wrote:

> On Sun, 17 Mar 2002, Joe wrote:
>
> > That MIGHT work but I don't recommend it. The 1.2M drive has
> > compatibility problesm with the 360k drives and it has the sme compatility
> > problems with the QD drive.
>
> Actually, it is NOT the sme compatility, (nor the same compatability :-)
> problems. The big problem with 360K in 1.2M is the head width. THAT is
> OK for "QD". But there can be some problems sometimes with trying to do
> "QD" with 1.2M, since sometimes it can be difficult to get it to switch
> density without also switching into "double-stepping" mode.

  Erck. That distant splash you just heard was the sound of Doc hitting
the bottom of the well. We passed the "All Greek To Me" phase awhile
back.
  So. The "fd0h720" device on my Debian Linux machine is defined as
"/dev/fd0h720 5.25" 720K in a 1200K drive"
  Will the 1.2M drive write reliable QD disks? Note that I said "write
reliable" not "reliably write". Several tries is no biggie.

> Correct spelling. 360K (AND "QD") is 300 Oerstedts; 1.2M is 600
> Oerstedts.

  Uh. OK. In dumbass terms, does that mean "no go"?

> > That should work as long as the PC understands the file structure. You
> Pretty EXTREME assumption! Not much besides CP/M,MP/M understands CP/M
> file system and DIRectory structure.
>
> > may need to use 22disk or something similar that understands the Altos
> > structure.

  No, dd doesn't care in the slightest what the file structure is. I've
imaged disks with filesystems totally unknown to Linux with dd.
Blocksize is sometimes an issue, but I've found that setting blocksize
to "1" fixes that just fine.
  Or, if I had a copy of 22disk (yeah, I'll google in a minute) I
suppose I could boot to DOS and do that. Does 22disk understand dd
images? (Andreas already cut to the chase & imaged a couple of trial
runs for me)

        Doc
Received on Sun Mar 17 2002 - 18:20:38 GMT