On Mon, Jun 23, 2025 at 3:59 AM Frank Leonhardt via cctalk <[email protected]> wrote:
> > There was a version of the Silent 700 terminal which had a unit on top > > containing 2 digital cassette drives [1]. These 'replaced' the paper > > tape punch and reader of other ASR terminals, I think you could save > > data from either the line or keyboard onto a caseette (equivelent of > > punching paper tape), copy from one to the other editing as you go and > > send the data from cassette to the line or printer (equvalent of > > reading a paper tape). > > > > [1] Same dimensions as a normal audio Compact Cassette but with a > > different grade of tape (higher coercivity?). You can identify the > > cassettes by the slightly off-centre notch in the rear edge. > > I never saw one of those, but that's the sort of thing I was as talking > about. The BIOS on a lot of the 8-bit micro boards I used was agnostic > as to whether it was a cassette tape interface or serial reader/punch. > The only snag was that the cassette couldn't start and stop on a > per-character basis so you couldn't realistically make a tape by keying > as you could with paper, and you had to insert nulls on the end of a CR > to allow time for processing a line that had just been input. Microsoft > BASIC had a NULL command to set the number of nulls required. So how, if > it could, did this Silent 700 make a keyed tape? These were not normal audio cassette recorders. They were units with several motors and solenoids so that the tape motion was controlled by the electronics. The 'ASR unit' -- the unit bolted on top of the normal Silent 700 -- contained buffer RAM, I think the data on the tape was stored in blocks so when doing key-to-tape, your keystrokes were stored in the buffer, then when the buffer was full, a block of data was written to tape. There were several such models. The older one was the ASR733 which was all TTL. The ASR742 had a 8008 in the main part of the terminal but I think the tape unit was still all TTL. FWIW I am sure I've seen single tape drives with a pair of RS232 sockets on the back to link between a terminal and modem and give 'ASR' facilities -- recording data to tape in blocks and replaying it later. -tony
