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Portability before Windows or any other system became mainstream. For example, Hitchhiker's Guide to the Galaxy (the original text adventure) was available on i
by tannhaeuser 4y ago
Portability before Windows or any other system became mainstream. For example, Hitchhiker's Guide to the Galaxy (the original text adventure) was available on it (and so did early text processors though I personally can't speak with hands-on experience here). Technically, CP/M isn't even an O/S in the "modern" sense taking Unix as a point of reference - Z80 and 8086 didn't even have an MMU so no kernel/userspace memory protection or process isolation. CP/M, like DOS, is rather an extended BIOS with a file system (as it says on the tin: control program for microcomputers) acting as portability lib once a program is loaded, plus a couple of interrupt handlers for screen refresh etc. I guess.
- varjag 4y agoIt was an operating system in the sense it abstracted much of the hardware into portable syscalls and came with a set of practical utility programs. Really the only assumption hardware had to conform was a certain memory map layout. Process isolation does not make much sense on a 2mhz 8 bit CPU with 64Kb address space anyway. MS DOS didn't do that either, and there are still modern embedded OSes that don't do process isolation.
- rbanffy 4y agoIf you look at some OSs that have been around for a very long time, they are quite minimalistic. While deeply alien to the Unix crowd, OSs like MCP or zOS are remarkably simple in what they do.