Written on the 15th March 2025.
I'm writing this on a black and yellow screen that is 38 years old, and I'm really enjoying it.
When I was a student I heard word from a friend that a local company were getting rid of their old minicomputer system.
The minicomputer was about the size of a large fridge and connected to a bunch of screens, called "terminals". These terminals aren't any use on their own; they need to talk to a separate computer. This was usually in an air conditioned "machine hall" - similar to the cloud datacentres of today.
The company had an office near the Usher Hall in the centre of Edinburgh, so a bunch of us nerds descended one Friday night and were invited to haul away what we could carry.
Unfortunately the DEC Microvax mini computer (being the size of a fridge) had to stay (the bus company gets a bit upset with this kind of thing), but I figured I could carry a VT320 terminal under my arm.
Apart from a few uses the terminal has sat unused for many years since, but I thought it would be nice to dig it out, blow the dust off and write this blog post using it.
The march of progress since the 1970s means that the terminal can connect to a modern laptop which is a bit easier than having to bring along a fridge. (Although by "modern laptop" I mean my 15 year old netbook computer, considered obsolete today).
I've got to admit: I'm really enjoying writing this on the terminal. The screen scrolls quite slowly and this gives it quite a calm feeling. There is nothing on the screen apart from the text I'm writing. The text is a lovely glowing amber colour, which feels warming.
I think we need more distraction free computing. Some might think that a 38-year old computer screen is obsolete, but I think we can learn from these systems. Why do people have to throw out computers every three years only to buy a new one which does just the same thing, only with more adverts and distractions?
If you want more:
- "LGR" has made a good video (YouTube) DEC VT320: The Classic 1987 Library Computer Terminal
The details, if you wish:
Graphics
There are lots of animations here: http://artscene.textfiles.com/vt100. Some of them are really creative. This can only be the result of the amazing drive to procrastinate instead of writing a dissertation. Some of the people signed their creations - I wonder where they are now, some forty something years later?
The VT320 is one of the fancier terminals. It has 96 user definable characters and this allows sort-of graphics. https://vt100.net/dec/vt320/soft_characters. We played around with the 'gif320' program that lets you display images on the screen (with a bit of imagination), which made the picture above.
The Linux configuration
The Linux operating system could be considered the grand-child of one of the UNIX operating systems that ran on these big old computers. It may have evolved to run on modern computers with large colour screens, but it can still talk to these old terminals. The Edinburgh Hacklab has the necessary cables, so off I headed (Or so I thought, but not quite - thanks Tim for coming to my rescue).
I used an FTDI-232 USB to serial cable to connect to my old netbook. A CH340 adapter looked like it would work, but often hung, for reasons unknown. A null-modem adapter is needed, along with a 25pin to 9pin connection cable.
The netbook is running the 'Antix' Linux distribution, which doesn't use systemd. I edited the '/etc/inittab' file and added the following line:
U0:23:respawn:/sbin/getty -L ttyUSB0 9600 vt100
…the process is different for Linux distributions running 'systemd'.
The terminal "comm settings" were set to:
- Xoff at 128
- RS-232, data leads only
- Transmit=9600, Receive=Transmit
I wrote the post using the 'vim' editor, but emacs also worked, though it did crash sometimes.
https://vt100.net has lots of documentation.
The great-grandfather of the VT320 - the DEC VT05 terminal looks (in my opinion) really great, in a 1970s retro-future way.
