4 ms·

The original of this Microware OS-9 was my first exposure to a "unix like" operating system in the 80s. It was pretty amazing that a mutli-user, multitasking o

The original of this Microware OS-9 was my first exposure to a "unix like" operating system in the 80s. It was pretty amazing that a mutli-user, multitasking operating system kernel can fit in 8k.

hashmash 5y ago
Even more amazing is that OS-9 was available for the "toy" Color Computer 15 years before multitasking became available for Windows or MacOS. The only thing preventing the CoCo from supporting safe multi-user interaction is an MMU that restricted higher address ranges. This would make it impossible to change the interrupt handlers, although interrupts could still be masked. The 6809 NMI feature (non-maskable interrupt) when combined with the MMU could then be used to jump back into kernel mode.
- skissane 5y ago
  > The only thing preventing the CoCo from supporting safe multi-user interaction is an MMU that restricted higher address ranges I don't think that would have stopped people from actively using it as a multi-user system in its heyday. I think other systems used for multi-user computing at the same time often had similar security deficits (examples: MP/M, PICK, MUMPS, Alpha Microsystems AMOS) Standards and expectations were a lot lower back then, and much greater reliance was placed on trusting users, and the obscurity of whatever security holes existed
- jjav 5y ago
  > Even more amazing is that OS-9 was available for the "toy" Color Computer 15 years before multitasking became available for Windows or MacOS. Indeed. OS-9 on the CoCo is what I grew up on and it spoiled me for all mainstream systems later when I realized how inferior they were to what I got used to as a kid. Multi-tasking multi-user OS on an 8 bit 6809 with 128K of RAM (and a price of just a few hundred dollars, back when an IBM PC was thousands). It also made me feel very familiar when I first encountered various UNIX systems so the transition was easy.
  - canadian_tired 5y ago
    You and me both. I ran OS-9 on my CoCo 1 in 64Kb RAM... sometime in '84 - '85. Could not do a lot, but it gave me a bit of grounding when I was dropped into SCO Unix in the late 80's.
    - jjav 5y ago
      Oh right, there was OS-9 Level I which ran on the CoCo 1 and 2, but with the max of 64K it was fairly limited in practice, although still a great learning platform. Later there was OS-9 Level II on the CoCo3 which was much more usable as a daily driver OS.

The original of this Microware OS-9 was my first exposure to a "unix like" operating system in the 80s. It was pretty amazing that a mutli-user, multitasking operating system kernel can fit in 8k.

hashmash 5y ago

Even more amazing is that OS-9 was available for the "toy" Color Computer 15 years before multitasking became available for Windows or MacOS. The only thing preventing the CoCo from supporting safe multi-user interaction is an MMU that restricted higher address ranges. This would make it impossible to change the interrupt handlers, although interrupts could still be masked. The 6809 NMI feature (non-maskable interrupt) when combined with the MMU could then be used to jump back into kernel mode.

skissane 5y ago
> The only thing preventing the CoCo from supporting safe multi-user interaction is an MMU that restricted higher address ranges I don't think that would have stopped people from actively using it as a multi-user system in its heyday. I think other systems used for multi-user computing at the same time often had similar security deficits (examples: MP/M, PICK, MUMPS, Alpha Microsystems AMOS) Standards and expectations were a lot lower back then, and much greater reliance was placed on trusting users, and the obscurity of whatever security holes existed
jjav 5y ago
> Even more amazing is that OS-9 was available for the "toy" Color Computer 15 years before multitasking became available for Windows or MacOS. Indeed. OS-9 on the CoCo is what I grew up on and it spoiled me for all mainstream systems later when I realized how inferior they were to what I got used to as a kid. Multi-tasking multi-user OS on an 8 bit 6809 with 128K of RAM (and a price of just a few hundred dollars, back when an IBM PC was thousands). It also made me feel very familiar when I first encountered various UNIX systems so the transition was easy.
- canadian_tired 5y ago
  You and me both. I ran OS-9 on my CoCo 1 in 64Kb RAM... sometime in '84 - '85. Could not do a lot, but it gave me a bit of grounding when I was dropped into SCO Unix in the late 80's.
  - jjav 5y ago
    Oh right, there was OS-9 Level I which ran on the CoCo 1 and 2, but with the max of 64K it was fairly limited in practice, although still a great learning platform. Later there was OS-9 Level II on the CoCo3 which was much more usable as a daily driver OS.