General Unix-pc Stuff

C M Votava cmv at cbnewsc.ATT.COM
Sat Sep 9 02:03:01 AEST 1989


Well, I've queue'd up enough gunk to justify a netnews posting, so here's
a bunch of general stuff.

ITEM #1
I've been talking with Alloy about the source code for the DOS-73 board. Half
of the code they have (the stuff that gets "pumped" to the board) but they
have apparently "lost" the source for all of the stuff that runs on the
unix side (the device driver, screen painter, etc.). If you know of anybody
that might have a copy of this code please have them contact Alloy at
(508-481-8500 ask for Sue Nevue) as they really want to get this back.

ITEM #2
I've also written a program (not ready for posting yet), that allows you to
examine and modify the raw bits on a disk (hard or floppy) including the
boot sector. When you run the command, reads bits off of the disk starting
at the beginning (/dev/rfp020 if you do the floppy), and writes these bits
into an ascii file in a format similar to od(1). You can then edit these
bits with vi(1) and re-write the new bit pattern back on to the disk. The
main use for this command was to allow folks to format MS-DOS disks by
copying the boot sector of an already formatted MS-DOS disk to a blank one.
Other uses that have become evident with this tool are things like examining
the cpio sequence numbers on a series of backup disks (and modifying them
if needed), and changing VHB parameters on hard disks other uses could be
such things as patching 3b2 floppies to make them unixpc readable (if you
have the 720K floppy installed). It still needs work, but if there is enough
interest I'll try to get it in shape and post it.

ITEM #3
I've just successfully added an on/off switch for the monitor on my unixpc,
after reading the article by (wtm at impulse.UUCP - Thanks Bill!). Turning the
monitor on and off while the rest of the machine runs has no effect on it other
than saving about 15 watts of power. Bill says that that sometimes when
flyback transformers fail, they catch on fire, and he didn't like the idea
of that happening while he was not home. It seemed like a good idea to me
to be able to turn it on and off, so I installed the switch. If there's enough
interest on how I did this, I'll post instructions to the net.

ITEM #4
For all of you voice power fans, I've just verified the bus lines labelled
"Audio From Tape", "Audio From Phone Line" and "Audio To Phone Line" actually
go where the schematics say they go. This means that with a couple of white
wires, and some clever programming we can pipe the voice power output through
the on board speaker, without tying up any phone jacks! With even more
programming, we can handle 3 phone lines, have music play while on
hold, playback/record to/from an in-progress phone conversation, slice, dice
peel, chop, grate, and make mounds and mounds of cole slaw.

ITEM #5
The publicly available AT&T description of the 882A modem chip (the one we
have in the unixpc) states that it can be run at 2400 baud in some kind
of "external mode" where there is an external high speed DSP attached to it.
I don't have all of the details in front of me now, but I'm hoping that
someone on the net will be familiar with this and let us know how to do it.
Otherwize I'll have to dig up the information myself. Can anybody help?

Let's be careful out there...

-Craig Votava

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