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

From: Don Maslin <donm_at_cts.com>
Date: Sun Mar 17 23:01:45 2002

On Sun, 17 Mar 2002, Doc wrote:

> 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)

No, 22Disk does not understand dd images, TeleDisk images, .dsk images,
or most any other kind. It is only capable of reading, writing, and
formatting most CP/M disk formats. That is to say, it is capable of
formatting a DD blank as an Altos DSQD diskand and it is also capable of
writing available files to that disk. With a modification to the disk
definition and an image file of the boot track, it is possible to make
the new disk bootable also. This assumes that either the whole of CP/M
is on the boot track, or that any needed loaders and CPM.SYS or MPM.SYS
are written to the data area.
                                                 - don

> Doc
>
>
>
>
Received on Sun Mar 17 2002 - 23:01:45 GMT