3 ms·

I remember magnetic tape being a lot more common than paper tape for the uses you suggest.

by mark-r 3y ago

jcrawfordor 3y ago
Yeah, magnetic tape is almost as old as the programmable computer, with the UNIVAC notably featuring magnetic tape drives. The main downside was that paper tape could be hand-punched using commodity equipment (often teletypes), while magnetic tape couldn't. Magnetic tape was also more expensive initially but I think that cost gap narrowed as paper tape fell out of use. Paper tape was probably becoming uncommon in most mainframe environments by the mid-1960s as the programming modality mostly became punched card source to magnetic tape object. Most IBM mainframes for example could IPL from any input channel, so while a paper tape reader was still a standard option on the 360 series in the mid-'60s, it probably only would have been used by more cash-strapped users. I think IBM generally stopped using paper tape as an exclusive or main I/O format by the end of the '50s. They were ahead of some of their competitors on that, though, probably due to their considerable expertise in both punched cards and magnetic tape. Some minicomputers continued to use paper tape for initial program loading well into the '70s though, including the PDPs used for Unix development. A number of these computers couldn't "boot" from the tape drives because they were I/O peripherals, while the console and its attendant paper tape punch/reader interacted directly with memory. This arrangement was sometimes called an "autoloader," where you could set a switch and a starting address and everything coming from the console keyboard/reader were put directly into memory sequentially. I have also seen videos of PDP users hand-toggling a program to read from a tape drive into memory; I think that's mostly a flourish for modern demonstrations and contemporary operators would have used the tape reader, but it's not a long enough program to be infeasible.

I remember magnetic tape being a lot more common than paper tape for the uses you suggest.

by mark-r 3y ago

I remember magnetic tape being a lot more common than paper tape for the uses you suggest.

Yeah, magnetic tape is almost as old as the programmable computer, with the UNIVAC notably featuring magnetic tape drives. The main downside was that paper tape could be hand-punched using commodity equipment (often teletypes), while magnetic tape couldn't. Magnetic tape was also more expensive initially but I think that cost gap narrowed as paper tape fell out of use. Paper tape was probably becoming uncommon in most mainframe environments by the mid-1960s as the programming modality mostly became punched card source to magnetic tape object. Most IBM mainframes for example could IPL from any input channel, so while a paper tape reader was still a standard option on the 360 series in the mid-'60s, it probably only would have been used by more cash-strapped users. I think IBM generally stopped using paper tape as an exclusive or main I/O format by the end of the '50s. They were ahead of some of their competitors on that, though, probably due to their considerable expertise in both punched cards and magnetic tape. Some minicomputers continued to use paper tape for initial program loading well into the '70s though, including the PDPs used for Unix development. A number of these computers couldn't "boot" from the tape drives because they were I/O peripherals, while the console and its attendant paper tape punch/reader interacted directly with memory. This arrangement was sometimes called an "autoloader," where you could set a switch and a starting address and everything coming from the console keyboard/reader were put directly into memory sequentially. I have also seen videos of PDP users hand-toggling a program to read from a tape drive into memory; I think that's mostly a flourish for modern demonstrations and contemporary operators would have used the tape reader, but it's not a long enough program to be infeasible.