Subject: Re: Paper tape Utilities/Images
From: "Dave Dunfield" <dave06a at dunfield.com>
Date: Thu, 28 Sep 2006 05:49:15 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
I have posted the utilities I created to read
paper tapes to my site in
the Software/Images section (near the bottom of the main page):
Dave.... have you considered supporting serially attached paper tape
reader/punches instead of just parallel devices?
I'd be happy to ... but I don't have a serial reader, so I need info on
the details of the interface (does it just send the raw serial stream as
read from the tape or is there some protocol around it).
Most of the serial PTR/PTP I used were not unlike the ASR33, The only
protocal was the usual; start and stop bits of serial comms. So for
every byte read by the reader you got a byte in serial form. It's just
a stream of chars (7 or 8bit) as punched on the tape. Reminder,
leader on most of those will be read as zeros so the average tape will
have a long line of zeros preceeding the content.
There was one I'd used (deep memory test ca1977) that used the CTS
line on the serial output to a corospnding line on the serial input
(both for punch and reader) as hardware flow control (their manual
called it hardware restraint). For that case CTS gated read(send bytes)
no read and for the punch case CTS gated the hosts ability to send the
next byte until the punch was ready for the next character. This was
only needed for slow (read case) hosts that could not accept the 300cps
read or a fast (relative) host that could over run the 75cps punch. Oddly
enough the unit (punch reader was Remex with custom third party board)
only had 4800 baud serial rate! Only saw one like it and the closest
Remex model was parallel only.
That's the hardware.. The tapes them selves could be Intel hex format, Moto
S records, binary, ASCI text or some vendors format (relocatable binary
or hex in some cases). Never minding DEC BIN and RIM formats. The oddest
and is old Intel BNPF!
FYI: for those not familiar that was a ROM submission format and Xasm
output format. Each byte was recorded on Ptape as example:
11000011 C3h BPPNNNNPPF (yes 10 chars on tape!)
00000000 00h BNNNNNNNNF
00010000 10h BNNNPNNNNF
The small advanatage is human readable. It was self cehcking at the char level
as anything other than BNPF was invalid. I was wasy to do a simple reader
needed only to sense three holes (sprocket and two bits) to discern if
the character was B,N,P or F making it very easy to serialize. I had
to do that back in '74 as a lab EE for a controller (8008 based) project.