Re: Kaypro Format

On Thu, 12 Jan 2006 13:21:51 GMT,
Dave.Dunfield@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (Dave Dunfield)
wrote:

Media compatability even between systems using very similar
hardware was/is one of the main problems I've encountered
for the last 30 years. Even now when I drag out a box there is
a box of media associated with it that is unique to it. Often the
media box is larger than the system!

>Kaypro disks are indeed numbered from sector 0 to 9. They also
>appear to be interleaved 4:1. Another "interesting" thing about
>Kaypro disks is that side-1 has the head field set to 0, and the
>sectors are numbered 10-19 (someone along the way must
>have thought it would be cool to think of a DS disk as one big
>logical track).

Maybe why the ampro using amprodsk is one of the few machines
that can read kaypro native media using a program to set up
the FDC for compatability.

I never willingly program floppy systems to produce a sector zero
or munge the field bits as it is likely to induce errors.

>Here is my IMDU utilitiy /D output for an image made from an
>original master Kaypro disk:
>
>IMageDisk Utility 1.09
>IMD 1.01: 3/08/2005 9:41:23
>KAYPRO MASTER
>CP/M version 2.2
>Copyright 1983 by Digital Research, Inc.
>S-BASIC
>Copyright 1983 Non-Linear Systems, Inc.
> 0/0 250 kbps DD 10x512
> 0 8 3 6 1 9 4 7 2 5
> D D D D D D D D D D
> 0/1 10 18 13 16 11 19 14 17 12 15
> HD: 0 0 0 0 0 0 0 0 0 0
> D D CE5 D D C00 D CE5 CE5 D
> 1/0 0 8 3 6 1 9 4 7 2 5
> C00 D D D C00 D D D C00 D
> 1/1 10 18 13 16 11 19 14 17 12 15
> HD: 0 0 0 0 0 0 0 0 0 0
> D D D D D D D D D D
> ... remaining tracks deleted ...
>80 tracks (40/40), 801 sectors (0 unavail, 524 data, 276 compressed)
>
>Note the sector numbering, and the presense of a "Sector Head map"
>record for the side 1 tracks indicating that it actually indicates head 0.
>
>>Of course that would make formatting or creating a kaypro disk
>>impossible for any system using 765based FDC. It's not supposed
>>permit sector number 0. The spec says it's not supposed to work
>>and tends to cause sector not found errors. That and IBM thought it
>>was a lousy idea for the standard 8" formats.
>
>No it doesn't - although it's officially not recommended, I have never
>yet encountered a 765 which had trouble with it. ImageDisk has no
>trouble reading/writing Kaypro disks.

I've found higher error rates usually sector not found errors. I
consider what kaypro did to be just bad.

>When I first designed my Cubix 6809 system, it was my first design
>with a 765 controller, and not knowing any better I numbered the
>sectors from zero ... Used a number variations of that system for
>many years, and never had disk problems (and never did change
>the sector numbering).

Using the 9216 helps there but the 765 is not spec'ed for it.

It was one of the odd things Tim and I discovered about formats
along the way.

>>I'm still trying to get B/P bios to work on SB180. The orignial
>>and one I wrote works so I know the hardware is good.
>
>SB-180 also has an interesting sector numbering - as you can
>see from the IMDU otput below, sectors are numbered from
>17-26 with an interleave of 2:1 (at least the heads are indicated
>correctly):

I considered that a oddity as well. Everyone wanted to use a generic
FDC/Floppy but prevent interchange it would appear. Yet almost
without fail an interchange tool is provided.

Begs the question why not program the floppy correctly instead of
playing games? If there was any one serious handicap to program
development and interchange it was the CP/M exchange media
problem. CP/M was a software bus short circuited by similar but
incompatable media. Often the solution short of transfer by serial
line was if you were lucky enough to have 8" and could do SSSD you
could. I have more than a dozen systems with 5.25" floppies and I
think four of the soft sectored systems can exchange media without
resorting to an exchange media program like multidsk or uniform.
Even that's because I rewrote the bios. After a while I resorted to
leaving out floppies and using either romdisk or fast serial protocal
to use disk resources on on of the bigger CP/M crates.


Allison
.

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