Date   : Wed, 05 Jul 1989 15:28:24 GMT
From   : sumax!amc-gw!sigma!bill@beaver.cs.washington.edu (William Swan)
Subject: Info wanted about Alspa Zero-Net

In article <89179.232817DDP100@PSUVM> DDP100@PSUVM.BITNET writes:
>   A friend recently acquired an Alspa Zero-Net system. The system disk
>seems to be crashed, unfortunately. From what we can tell in the manual we
>have, it will boot from Turbodos or CP/M. We have tried a DS/DD CP/M disk
>but it would not boot. Do we need a special CP/M format? These are 8 inch
>disks, by the way. Alspa seems to have gone out of business in mid 83 or
>at least thats where their ads drop off. I'd really appreciate any info.
>or suggestions anyone might have on this system. Thanks in advance.

The Alspa Zero-Net will boot TurboDos, I know, and might boot CP/M if the
BIOS was ever created for it (to my knowledge it never was, at least by
Alspa Computer, but I left there in early '83, a couple years before the
actual demise of the corporation - not that there was much doubt about the
eventual outcome long before then - but I digress...).

The Zero-Net disk formats are a bit unusual (Ron Alspaugh's forte -
optimising disk formats for speed :-), so you're not going to be able to
boot from just any DS/DD disk. A brief explanation:

First, the sector skew is encoded in the track image. In a "normal" disk,
the sector numbers are encoded 1-2-3-..., in the Zero-Net (actually all
Alspa DD formats are similar) they are encoded something like 1-4-7-2-5...
This eliminates the need for skew tables! :-) Still, the only penalty to
you for using an incorrectly sector-labelled disk would be slower 
performance.

A bigger problem arises in identifying the disk type. The Zero-Net used an
awful scheme the particulars of which I've forgotten over the past 6+ years.
I don't think it used the ACI-1/2 scheme of encoding the disk format in byte
0x7F of sector 1 track 0. As I recall (I'd have to look it up to be sure) it
saved it in the sector header, under disk SIDE! It goes something like: 0 
(and 1?) are standard CP/M SS/SD (IBM 3740) format, 2 & 3 are DS/SD, 3 & 4
are DD/SS, 5 & 6 are DD/DS (I seem to remember it went higher, but memory
escapes me right now).

The Zero-Net boots from a disk differently than most CP/M systems, which
normally boot from a reserved track and sector. Under Zero-Net, there are
no reserved tracks - excepting, of course, standard SS/SD disks. Instead,
the boot ROM, which has knowledge of all the disk formats, looks for a file
with a particular name, something like 0BOOT.COM, and loads and executes it. 
That file, the boot loader, then looks for another file presumably containing
the TurboDOS system image, and loads that.

All this by way of saying that you either need the two files on a SS/SD disk
to get going, or an Alspa-formatted DD disk. If you have other Alspa floppies
around, you might try them in case the system files are present on them.

Otherwise, there are two courses of action open to you:

1. Send me e-mail. I may have a Zero disk around (if I can get my ACI-2
TurboDOS system to boot). It's likely to be a very old and buggy version,
unhappily. The TurboDOS writers were madly revising the system at the time,
and the version 1.22? that I've an image of may be very old. 

2. Join the Alspa mailing list (which has been very quiet for several
months). I believe there are some Zero-Net owners there, and they may have
the scoop on more recent version. From my .mailrc file (edited...):
To join the list send request to:
       ...!ssyx.ucsc.edu!alspa-users-request
For submissions to the list:
       ...!ssyx.ucsc.edu!alspa-users


I would encourage followups to this to be conducted on the mailing list.


-- 
Bill Swan  entropy.ms.washington.edu!sigma!bill  Send postal address for info:
       Innocent but in prison in Washington State for 13.5 years:
       Ms. Debbie Runyan: incarcerated 01/1989, scheduled release 07/2002.
                          In now:  0 years,  5 months,  2 weeks,  1 day.