So if you had 6 of those, you could support 96 users. You could get expansion units too for the main bus:
https://www.reddit.com/r/retrobattlestations/comments/dpt47y...
"It takes up one ISA slot in the main PC, and then hauls the signal to the external box, where you can plug in up to 7 more cards, plus some RAM"
So, using 6 slots in the first box, and 6 slots in the next, and 16 port serial cards, that's in theory 192 users on RS-232 lines. Anyway, this is just a guess. I vaguely remember hearing of some actual (lesser) systems with lots of RS-232 ports, but don't recall exactly how they worked.
So, that's 12K to support 150 input buffers, plus probably at least 1K for each user dictionary on top of the shared dictionary (12K + 150K = 172K total). That is probably low -- if users might want 4K each that's 600K. Throw in 28K for an extensive base system to round things off and that is 640K for a great low-latency system supporting 150 users all simultaneously having a command line, assembler, compiler, linker, and editor. And I'd guess probably a database too on a shared 10MB hard disk. And it might even feel more responsive than many modern single-user systems (granted, expectations were lower back then for what you could actually do with a computer). So, yes, "640K of memory should be enough for 150 anyones." :-)
Related: "Why Modern Computers Struggle to Match the Input Latency of an Apple IIe" https://www.extremetech.com/computing/261148-modern-computer...
"Comparing the input latency of a modern PC with a system that’s 30-40 years old seems ridiculous on the face of it. Even if the computer on your desk or lap isn’t particularly new or very fast, it’s still clocked a thousand or more times faster than the cutting-edge technology of the 1980s, with multiple CPU cores, specialized decoder blocks, and support for video resolutions and detail levels on par with what science fiction of the era had dreamed up. In short, you’d think the comparison would be a one-sided blowout. In many cases, it is, but not with the winners you’d expect. ... The system with the lowest input latency — the amount of time between when you hit a key and that keystroke appears on the computer — is the Apple IIe, at 30ms ... This boils down to a single word: Complexity. For the purposes of this comparison, it doesn’t matter if you use macOS, Linux, or Windows. ..."
So if you had 6 of those, you could support 96 users. You could get expansion units too for the main bus: https://www.reddit.com/r/retrobattlestations/comments/dpt47y... "It takes up one ISA slot in the main PC, and then hauls the signal to the external box, where you can plug in up to 7 more cards, plus some RAM"
Which mentions: https://en.wikipedia.org/wiki/IBM_Personal_Computer_XT#Expan...
So, using 6 slots in the first box, and 6 slots in the next, and 16 port serial cards, that's in theory 192 users on RS-232 lines. Anyway, this is just a guess. I vaguely remember hearing of some actual (lesser) systems with lots of RS-232 ports, but don't recall exactly how they worked.
One thing about Forth is that it could cooperatively multitask essentially (almost) by just switching a dictionary pointer to one for each current user (along with a small terminal buffer of say 80 characters). https://groups.google.com/g/comp.lang.forth/c/Rh3stETjMls https://forth-standard.org/proposals/multi-tasking-proposal
So, that's 12K to support 150 input buffers, plus probably at least 1K for each user dictionary on top of the shared dictionary (12K + 150K = 172K total). That is probably low -- if users might want 4K each that's 600K. Throw in 28K for an extensive base system to round things off and that is 640K for a great low-latency system supporting 150 users all simultaneously having a command line, assembler, compiler, linker, and editor. And I'd guess probably a database too on a shared 10MB hard disk. And it might even feel more responsive than many modern single-user systems (granted, expectations were lower back then for what you could actually do with a computer). So, yes, "640K of memory should be enough for 150 anyones." :-)
Related: "Why Modern Computers Struggle to Match the Input Latency of an Apple IIe" https://www.extremetech.com/computing/261148-modern-computer... "Comparing the input latency of a modern PC with a system that’s 30-40 years old seems ridiculous on the face of it. Even if the computer on your desk or lap isn’t particularly new or very fast, it’s still clocked a thousand or more times faster than the cutting-edge technology of the 1980s, with multiple CPU cores, specialized decoder blocks, and support for video resolutions and detail levels on par with what science fiction of the era had dreamed up. In short, you’d think the comparison would be a one-sided blowout. In many cases, it is, but not with the winners you’d expect. ... The system with the lowest input latency — the amount of time between when you hit a key and that keystroke appears on the computer — is the Apple IIe, at 30ms ... This boils down to a single word: Complexity. For the purposes of this comparison, it doesn’t matter if you use macOS, Linux, or Windows. ..."
Thanks for the Otlet book reference! Got a copy just now: https://www.amazon.com/Cataloging-World-Otlet-Birth-Informat...