Taking a look at the 8051 code in an LK201 keyboard has been an interesting and educational diversion from the 8051 code in the #VT320 terminal that I’m _really_ interested in. For starters, almost everything about a keyboard is smaller – no external RAM, ROM, NVRAM or DUART, just the inbuilt serial buffer, 4K of code and 128 bytes of RAM. It has provided a way to improve my 8051 emulator from a collection of hacks for one purpose to a more reusable, hookable system. #retrocomputing
Now I can send key presses into the #VT320 emulation, I can explore set-up mode and save configurations to the nvram. This morning the terminal kept saying ‘NVR Error’ when I did that. Hmm, close examination revealed that I’d typo'd my implementation of the ER5911 SEEPROM and I’d swapped the opcodes for ‘Program Disable’ and ‘Erase All’ so I was not only erasing everything that’d just been saved, it took 20 ms to do that, when the nvram should’ve been ready immediately. Hurrah. #retrocomputing
It’s taken three weeks of effort to write emulators for the 8051 microcontroller, ER5911 SEEPROM, SCC2681 DUART and get frustrated over the timings required to make the firmware happy, but my #VT320 emulator now runs the original ROM far enough to pass POST. At this rate, I’ll have understood and annotated the rest of the code by its 40th birthday, and not a minute before. 😓 #retrocomputing
I’ve just started disassembling the ROM for Digital’s VT320 terminal, which contains an 8051. I'm using D52 to direct the disassembly. The 8051 has a 16-bit register DPTR, through which you can access either ROM or RAM, which are separate spaces, requiring two symbol tables. The documentation describes a directive "d" which can say, for each opcode address, which symbol table should be searched. Except ... it doesn't work. So, to fix D52 before the real job! #retrocomputing #VT100 #VT320
Sur la table d'opération un terminal #dec #digital #vt320 , le tube est un peu fatigué je reprends la procédure d'alignement de l'image pour voir si je peux un peu l'améliorer
#retrocomputing
DEC VT320: The Classic 1987 Library Computer Terminal

Digital Equipment Corporation built plenty of terminals in the 70s and 80s, but we're focusing on the VT320-C2. Amber monochrome, LK201 keyboard, and a favor...

YouTube

Now people may ask things like: "Why?" and the answer is: For a primitive approach to #SecureComputing.

  • Because loading the #OS into #RAM allows not just for a non-persistent setup like an #SSH-#Terminal (think #VT320 but better!) but being hard-wired as #ReadOnly means it's tamper proof by design when combined with an intrusion-detection & tamper-proof seals: Physical Access will be detectable and Remote Access cannot cause permanent damages.

And that may also be useful with other #ThinClient-like "aplianced" devices.

  • Basically for anything where #NetworkBoot ain't an option for whatever reasons!

https://www.youtube.com/watch?v=RuZUPpmXfT0 via @lazygamereviews

DEC VT320: The Classic 1987 Library Computer Terminal

Digital Equipment Corporation built plenty of terminals in the 70s and 80s, but we're focusing on the VT320-C2. Amber monochrome, LK201 keyboard, and a favor...

YouTube
Homelab update. #vt320

@Screwtapello

Inspired by this to style a Windows Terminal+PowerShell prompt like a VT320 term using your font and oh-my-posh.

Honestly I spent way too much time making it work, but it does look pretty cool.

The toolbar is an illusion, though - actually part of the prompt. I wish OMP had a way to "pin" a block at the top of the terminal.

(no I won't add the retro terminal effects in WT because it's ugly and annoying)

#RetroComputing #typography #OhMyPosh #PowerShell #WindowsTerminal #VT320

DEC VT320: The Classic 1987 Library Computer Terminal

Digital Equipment Corporation built plenty of terminals in the 70s and 80s, but we're focusing on the VT320-C2. Amber monochrome, LK201 keyboard, and a favor...

YouTube