VT78 - lots of questions - test-drb@ccmp.vtda.org

23 Dec 2000

On Dec 23, 14:18, David Gesswein wrote:
...
  >From: pete(a)dunnington.u-net.com (Pete Turnbull)

...
  >Is there anything in particular I should watch out
for when I power it up?

...
  This is an area of discussion.  The full treatment
[...]. 
Well, I would do most of that anyway, but I wondered if there were any
particular gotchas.  I assume not, so I'll just take normal care :-)

...
  >I don't have the RX01 drives [...] I also have
a set of RX02s 
...
  My VT78 is running off of RX02's set to RX8E mode.
 They also have the
 DB25 plug on the back which will connect directly to the VT78 cable.  If
 yours don't I should be able to dig up the pinout if you don't run across
 it in one of the manuals. 
I don't see a DB25, but Tony has said something similar, and I should be
able to hack an adaptor.  Thanks for the tip about RX8E mode -- that's one
of the things I was wondering about.

I assume that the difference between RX8E (= RXV11/RX11) mode, and RX28
mode, is the denisty supported?  ie, RX28 mode makes the drives behave as
RX02 rather than RX01?  Did'nt I read somewhere that some VT78s (or was it
only DECmates?) can use RX02 mode?

...
  I have WPS, RX02 and OS/78, and COS manuals online.  I
have a complete VT78
...
  printset but I have not scanned it yet.
 http://www.pdp8.net/query_docs/query.shtml 
That's extremely helpful -- thanks!  I knew you had several manuals but
I've not had time to browse yet.

...
  What is FOCAL-GT/RT? 
All I know is what the front of the manual says: FOCAL-GT is a version of
FOCAL-11 extended to use a GT40 with graphics as well as a teletype.  So in
fact, it's not relevant at all, as it's meant for an 11/05.  It was a red
herring, sorry.

...
  >I should have some 8" floppies, though
I'm not sure what's on them because
...
  I've not
actually found them yet :-)   Is there anything I should try
downloading from the net?
  I have OS/78, COS and WPS images online, poke around in
ftp://pdp8.net/images/

Even better, since I've unpacked al the boxes and can't find any VT78
floppies.  Lots of other things I forgot I had :-)  but not those.

...
  If you have a OS/8 variant on the floppy that may be
able to use my disk
 image dump and restore programs, dumprest.zip in
 ftp://pdp8.net/software/
 I have never actually tried to use it on the VT78, I write the images
 from the 8/E.

 If you find you don't have any bootable floppies I can make you one. 
Well, before I go that far, I might try to get 8" drives running on an old
PC that has an XT controler which *should* do SD, I think.  Can I use
something like PUTR to create a disk that way?

Thanks for the suggestions and help.

-- 

Pete						Peter Turnbull
						Network Manager
						Dept. of Computer Science
						University of York