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Old 12th May 2021, 4:59 am   #13
ortek_service
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Join Date: May 2018
Location: Northampton, Northamptonshire, UK.
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Default Re: MK14 computer with a OK-80a paper tape reader - what data required for the paper

I found this useful webpage about the original OP-80A: https://deramp.com/swtpc.com/OAE80_R...AE80_Index.htm which has a copy of the original manual, plus also has software listings to read tapes on 6800-systems. It seems from this document, that straight 8bit binary format (no header characters, checksum, address pointers, etc) could be used (on black tape?), for simplicity of entering a small program to handle that:
https://deramp.com/swtpc.com/OAE80_R...NewsLetter.pdf

There's not much here https://en.wikipedia.org/wiki/Punched_tape on the individual standards, but these show a number of different systems
(Mainly what seems the most common later 'standards' of 7bit ASCII + Parity / 8 bit binary)
https://www.cryptomuseum.com/telex/r...es/ecma_10.pdf
http://www.chilton-computing.org.uk/...apman/p015.htm
https://www.cryptomuseum.com/telex/r...es/ecma_10.pdf

Although no mention of header characters, checksum, address pointers etc. with these - Which I would expect to be documented somewhere, as Motorola did an EXORtape for their 6800 EXORciser etc. system, supply software on this. As well as various other systems like Altair around then (But maybe wasn't common on the SC/MP)

You could in theory make your own tapes, either totally manually: https://www.cryptomuseum.com/telex/repair/index.htm
or using a silhouette portrait printer (a bit costly at around £200?) to produce short strips with small index holes on blank paper etc, as well as a DIY reader:
https://www.instructables.com/DIY-Pa...er-and-Reader/

I'm sure I've got a roll of 1" wide? completely blank paper tape, a picked-up a few years ago (from a Radio Rally ?). So might still be able to get this (TNMoC must get through a bit on colossus, running in a continuous loop but only 5bit - It's surprising that hand-pulling of the tape on the OP-80A could get to 5,000 cps speed that involved a high-power lamp in colossus and expensive fast selenium? sensors (Although that was before semiconductors)

Last edited by ortek_service; 12th May 2021 at 5:19 am.
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