26 Aug
2006
26 Aug
'06
5:06 p.m.
Subject: Re: Paper tape and 8th bit?
From: woodelf <bfranchuk at jetnet.ab.ca>
Date: Sat, 26 Aug 2006 16:48:38 -0600
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at
classiccmp.org>
Chuck Guzis wrote:
PT and many of the 8080 micros didn't use the punch/reader (ASR33 usually)
in the same way as the PDP-8 and onter Minis. So conventions existed but
didn't always get applied the same.
It's not a bin tape, the manual has the source listing. Its a program
"LIST"
of a PT 5k basic program that loads a long list of DATA nnn,nnn into memory
at an address and also pokes the output code of the program to point to VDM1
or Nominal IO depending of sense switch 8 (IN FF; ANI 80; JZ xxxx). Works on
IMSAI or Altair front pannal systems,useless for NS* (no sense sw at FFh).
I still have and use a VDM-1 in a Netronics Explorer 8085. I havent used PT
software since '76ish as I wrote a more compact minimal VT52 screen
emulation for it.
Allison
If you look at the preceding character, is there any correlation to the 8th
bit of the next one? The 8th bit just might be garbage left over and not
masked out.
It could be binary.The driver is loaded in the top of memory, and
seems to patch over a TTY driver. I don't have manual handy
but it does have a bootstrap loader @ 80H I think, the first
256 bytes to load in a hex loader.