a friend of mine sent me these photos of an IBM MT/ST tape (magnetic tape / selectric typewriter).

[tubetime@mastodon.social]

@philcowans probably 1970s.

[tapewolf@meow.social]

@tubetime I will have to try and get a magnetic viewer someday, but they're not cheap

[sverx@mastodon.gamedev.place]

@tubetime you need to both bring the carriage back *and* move the paper one line

[vathpela@infosec.exchange]

@penguin42 @tubetime seems like the blank in the middle also makes sense if it's transcribed from (or merely some design bits are borrowed from) paper tape with a center tracking sprocket.

[vathpela@infosec.exchange]

@mwichary @tubetime I wonder if it's intended to be fit for mechanical transcription to some form of paper tape, without translation, and so it actually has to represent the tracking sprocket holes.

[mwichary@mastodon.online]

@vathpela @tubetime That’s exactly what I was thinking of, too!!!

[deborahh@cosocial.ca]

@tubetime @ShaulaEvans what?!?!

[carpetbomberz@mastodon.online]

@tubetime @bitsavers

All the *kewl kids are doin' it

[tubetime@mastodon.social]

@mwichary @vathpela possible but also the documentation refers to a search bit, so presumably you could set a marker bit there.

[bitsavers@oldbytes.space]

@carpetbomberz @tubetime

and thanks to @tubetime someone will have figured it out for them, assuming "doin' it" means reading old magtape selectric cartridges

[carpetbomberz@mastodon.online]

@bitsavers @tubetime

that is what doin' it means in this context ️

[vathpela@infosec.exchange]

@tubetime @mwichary making that a dedicated bit instead of a symbol sure seems weird.

[snowfox@tech.lgbt]

@tubetime Interesting bit numbers. 1, 2, 2a(?), 5, 10, 20; maybe it was originally for a decimal system?

The * on the 2's Ck/Sft suggests it supports both uppercase and lowercase (lining/text?) digits which is interesting since there's no separate 1, so no way to encode "lowercase" 1.

[acsawdey@fosstodon.org]

@tubetime So is the MT/ST before or after the "Magcard Composer" which was basically a Selectric that could key in text and store it on what looked like a punch card but was covered with magnetic media. Then you'd put in the expensive mineral-coat paper and play it back to get a nice error-free galley that you could paste up into book form. Low end typesetting in the late 1970's ...

[mwichary@mastodon.online]

@vathpela @tubetime I don’t know what “search” is exactly and Internet Archive is down, but if it’s something like beginning of a new section, I can see the value of a separate hole – it could potentially allow to find sections faster (random access)?

[somevegancheeseisok@mastodon.social]

@tubetime holy shit this is so cool

[dukeduke@mastodon.social]

@acsawdey @tubetime I snagged a Magcard Selectric from a govt auction, back in the '80s. The giant magcard unit became a small side table to the desk, while the Selectric became our home typewriter. I loved typing on those beasts.

[pesco@bsd.network]

@tubetime ​ wie geil ist magnaviewer

[petes_bread_eqn_xls@mastodo.neoliber.al]

@tubetime fun fact: Len Deighton’s historical fiction book “Bomber” was written on an MT/ST.

[ruenahcmohr@infosec.exchange]

@tubetime oh I found a set of code tables on a crazy old book I meant to post, this reply is actually just to remind me to POST IT RUE.