4 ms·

I'm still unclear on this - I notice from online that Linux, for example, supports up to 256 TTY devices by default. How might one go about actually physically

by b800h 3y ago

I'm still unclear on this - I notice from online that Linux, for example, supports up to 256 TTY devices by default. How might one go about actually physically hooking up that many devices these days? Is a terminal concentrator still available?

convolvatron 3y ago
16 port isa cards were a thing. apparently they are still made. not fond memories.
kens 3y ago
Here's an example of a PCI card that supports 16 RS-232 devices: https://www.amazon.com/StarTech-com-PCI-Express-Serial-Card/dp/B06XSKGB64 https://www.amazon.com/StarTech-com-PCI-Express-Serial-Card/... (not an affiliate link)
yjftsjthsd-h 3y ago
If you asked me to do it, I'd probably see how many serial/USB adapters I could plug into how many USB hubs attached to a single box. I can't see any reason it wouldn't work, and the parts are cheap enough, and not even particularly obscure. I suspect the failure point would be something in the stack not expecting to have to operate like that and having insufficient performance, but this is all speculative.
marcus0x62 3y ago
In the mid 90’s we used Cyclades multi-port serial cards to do this. These were PCI cards that connected to one or more breakout boxes that contained (in our case) 16 RS-232 ports each. We had 48 total ports connected to a 60mhz Pentium with 32MB of RAM. This was a decidedly low budget solution, even at the time. There were also commercial offerings from vendors like Cisco and Livingston that provided a terminal server in a dedicated appliance form factor. edit the breakout boxes look like this: https://149707953.v2.pressablecdn.com/wp-content/uploads/imported/7/27/USED-CYCLADES-16-PORT-SERIAL-MODULE-SM16-170818533027-580x871.jpg https://149707953.v2.pressablecdn.com/wp-content/uploads/imp...
EvanAnderson 3y ago
Perle continues to make the IOLAN device concentrators (they were Chase brand when I used them in the 90s). Today they’re marketed as “device servers” for connecting console ports on embedded devices to IP networks but you could still serve dumb terminals from them just fine.
johnklos 3y ago
Back then there were dedicated boards with large numbers of serial ports. These days you can get PCI(e) serial boards with, say, 16 serial ports. Personally, I'm using a Commodore A2232 seven port serial board in my Amiga 4000, which has its own 65CE02 CPU to offload work from the main CPU.
- icedchai 3y ago
  What are you using it for? When I was a teenager, I dreamed of getting one of those boards so I could have a multi-line BBS on my Amiga!
  - johnklos 3y ago
    I use it to have serial consoles on a number of other machines for remote administration. The sessions get started automatically on boot with tmux and cu, so it's very convenient and easy - much easier than having a ton of USB-serial adapters hanging off of a newer machine.

by b800h 3y ago

convolvatron 3y ago

16 port isa cards were a thing. apparently they are still made. not fond memories.

kens 3y ago

Here's an example of a PCI card that supports 16 RS-232 devices: https://www.amazon.com/StarTech-com-PCI-Express-Serial-Card/dp/B06XSKGB64 https://www.amazon.com/StarTech-com-PCI-Express-Serial-Card/... (not an affiliate link)

yjftsjthsd-h 3y ago

If you asked me to do it, I'd probably see how many serial/USB adapters I could plug into how many USB hubs attached to a single box. I can't see any reason it wouldn't work, and the parts are cheap enough, and not even particularly obscure. I suspect the failure point would be something in the stack not expecting to have to operate like that and having insufficient performance, but this is all speculative.

marcus0x62 3y ago

In the mid 90’s we used Cyclades multi-port serial cards to do this. These were PCI cards that connected to one or more breakout boxes that contained (in our case) 16 RS-232 ports each. We had 48 total ports connected to a 60mhz Pentium with 32MB of RAM. This was a decidedly low budget solution, even at the time. There were also commercial offerings from vendors like Cisco and Livingston that provided a terminal server in a dedicated appliance form factor. edit the breakout boxes look like this: https://149707953.v2.pressablecdn.com/wp-content/uploads/imported/7/27/USED-CYCLADES-16-PORT-SERIAL-MODULE-SM16-170818533027-580x871.jpg https://149707953.v2.pressablecdn.com/wp-content/uploads/imp...

EvanAnderson 3y ago

Perle continues to make the IOLAN device concentrators (they were Chase brand when I used them in the 90s). Today they’re marketed as “device servers” for connecting console ports on embedded devices to IP networks but you could still serve dumb terminals from them just fine.

johnklos 3y ago

Back then there were dedicated boards with large numbers of serial ports. These days you can get PCI(e) serial boards with, say, 16 serial ports. Personally, I'm using a Commodore A2232 seven port serial board in my Amiga 4000, which has its own 65CE02 CPU to offload work from the main CPU.

icedchai 3y ago
What are you using it for? When I was a teenager, I dreamed of getting one of those boards so I could have a multi-line BBS on my Amiga!
- johnklos 3y ago
  I use it to have serial consoles on a number of other machines for remote administration. The sessions get started automatically on boot with tmux and cu, so it's very convenient and easy - much easier than having a ton of USB-serial adapters hanging off of a newer machine.