Quote:
Originally Posted by nana77
On a mobile phone, or tablet?
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We had 32 bit multitasking by the time of analogue mobile/cell, never mind CDMA/GSM (2G).
Multitasking on 8bit and 16bit CPUs was common in the 1980s, but first tablets were PDAs. The Gridpad was 1989 PC type tablet, but earlier tablet type pocket devices existed.
UNIX is from 1976,
There are different kinds of multitasking.
Occam (1983) and Modula-2 (1978) have co-operative multi-tasking in the programming language. Modula-2 is on 8bit, 16bit and 32 bit CPUs. The Transputer had multiprocessor and concurrency support.
You can write co-operative or pre-emptive multitasking in assembler and most computer languages for most CPUs. It typically needs much more RAM to be useful. Security and process isolation are issues on general purpose OS and may need support of Memory Management hardware and CPU privilege levels not available on most 8bit and primitive pseudo 16 bit CPUs such as the 8088/8086. The first viable Intel CPU for a UNIX type OS was the 80286, and MS sold Xenix for it. Later MS sold off Xenix. OS/2 was for the 286. MS had their own version of OS/2 in 1989.
Multiuser is a separate issue from Multitasking. Also multiple simultaneous users may not have per user multitasking.
Compare
MP/M 80 (ran on 8 bit CPU with a multitasking kernel for multiple users at the same time each running only one CP/M program at a time.) There was also MP/M and Concurrent DOS for the 8088/8086 which could even run Win 3.x programs in Real mode.
Win 3.x in Enhanced mode is single user and co-operative multitasking.
Win NT is multiple users, but only one at a time originally, but pre-emptive multitasking.
UNIX, BSD and Linux can support multiple users at the same time and multitasking.
A Real Time OS may or may not have multitasking and / or multiple CPUs.
There is nothing at all novel about Sailfish.