Steve, Tapes were definitely expensive enough to be reused, but for something as important as system software source code, people tended to keep them and rotate through backup tapes. 7- and 9-track tapes each had a parity bit and 6 or 8 bits of data. I believe they attempted to distribute the original Fortran compiler (1957) as a deck of “binary” punched cards, but had trouble with the card punches and duplicating equipment handling so many holes.
> On Mar 3, 2026, at 5:19 PM, Steve Lewis <[email protected]> wrote: > > Fantastic, thanks for sharing that Paul ! > > I see "SOS" (SHARE OS) from 1959 and expected it was a similar workflow: > initially on punched cards, intermediate fixes done on tape, then back to > cards-- for a brief time, wouldn't tapes be a form of your storage space? so > as you were "done" with the system - or a program completed and moved to the > next batch-sequence - someone else could re-use the tape? (I recall earlier > OS's, maybe CTSS, being like that -- if you logged out without saving your > workspace, you'd lose it ) Then c. 1962ish, SOS morphed into IBM IBSYS. By > that point, maybe nearly all the interactive development was done on 7 or > 9-track? ( was there an 8-track? I think Univac had an 8-track at same > point? ) > > I have seen the 1401 demo at CHM, so this helps put it more into perspective. > > > -Steve > > > > > On Tue, Mar 3, 2026 at 4:47 PM Paul McJones via cctalk <[email protected] > <mailto:[email protected]>> wrote: >> As a student at UC Berkeley (1967-1971), I had a part-time job at the >> Computer Center, which ran a CDC 6400 under SCOPE. We punched cards, >> transferred them to magnetic tape, and used UPDATE to maintain logical >> decks. I personally used this technology while working on CAL SNOBOL and CAL >> TSS. Once we got CAL TSS far enough along to support development (on a >> second CDC 6400), we switched to Teletypes (a mixture of Model 33’s and >> Model 35’s). I still have source code for CAL SNOBOL because of archivists >> at U. of Arizona and U. of Texas, but most of the source code for CAL TSS >> was lost (listings survive). >> >> >> Paul McJones >> >> https://www.mcjones.org/CAL_SNOBOL/ >> https://caltss.computerhistory.org/
