On 6/28/25 10:49, D. Hugh Redelmeier via Talk wrote:
From: James Knott via Talk <talk@lists.gtalug.org> We didn't have any Wyse terminals, mostly DEC & Data Generals, though we also had a bunch on Ontel smart terminals, which, IIRC, were made in Canada. I also used to work on some really dumb (retarded? 😉) terminals that had absolutely no smarts and relied on a Data General Nova to do simple text editing, etc.. These were so old they used an acoustic delay line for memory! All I can find about Ontel seems to be about smart terminals, like the OP-1. You must have had an earlier model.
Yes, it was a smart terminal. It used an 8080 CPU and could be programmed to emulate other terminals
To use an acoustic delay line, they must have been really really old. You would know better than I because you repaired them.
I remember IBM 2260 display terminals. A bank of them was driven by one controller. The controller used an acoustic delay line for the screen memory. (I had always been told that it was a magneto-restrictive delay line, but Wikipedia says otherwise). This terminal system was introduced in 1964, before IBM used integrated circuits. <https://en.wikipedia.org/wiki/IBM_2260>
Magneto-restrictive sounds about right. The terminals were made by "VST". They were connected to a Data General Nova 800 and used for creating telegrams. Later on, the telegram system moved to a pair of Eclipse computers and used the Ontel terminals.
By the time that "glass TTYs" came on the scene, ICs were available and other forms of memory were used. I remember getting a large shift-register memory from a Datapoint terminal (the Intel 8008 architecture matches the Datapoint 2200's processor).
I also used to work on the 2200 on the CN TRACS system, which was used to keep track of freight trains consists. It was originally supposed to use the 8008, but since it couldn't deliver the required performance, Datapoint created their own CPU board. That system used ASCII internally and to the printer, Baudot for remote printer lines, EBCDIC on the serial lines to a mainframe computer in Montreal and Hollerith in the card punch/reader. I serviced all that gear, along with the data connections to elsewhere. The 2200 was also where I first came across BASIC.
Remember that a dumb terminal only needed 24 x 80 characters of buffer. Now we expect bit-mapped displays -- much larger frame buffers. Those display architectures were held back by memory costs.
I used a Tektronix terminal on a PDP-8/i (1968/1969). It used a storage CRT so that it didn't need to have a buffer! It felt a bit like using an e-ink display because the whole screen had to be rewritten to make a change (additions didn't require a refresh). The PDP-8/i software was written for a teletype, so basically the user would clear the screen when it filled up -- sort of like putting a new piece of paper in a teletype.
Our PDP-8i was used with Phillips terminals in an older telegram system. There were a dozen terminals, IIRC.