jerry@altos86.Altos.COM (Jerry Gardner) (05/25/90)
In article <1217.2656b909@gp.govt.nz> don@gp.govt.nz (Don Stokes) writes: >The Amiga and other small system (ie no memory management) OSs do similar >things, but have the rather severe limitation that all code running on >them must be "well behaved". This is generally fine for embedded systems >etc, but hopeless for any serious timesharing, especially if the >I suppose it comes back to the old question of "what is multi-user". It >could be argued that raw Unix, without any real schemes for controlling A company that I worked for at one time, Qantel, sells large, multi-user business computer systems based on an architecture that has no memory protection at all. And since there is no clock interrupt, the operating system is not preemptive--tasks have to execute a task break system call to return control to the operating system. These systems support, in some cases, over 64 users--but at a price. Any program that has not been extensively tested has a good chance of bringing the machine to a grinding halt, and since there is no memory protection, security is virtually nonexistant. -- Jerry Gardner, NJ6A Altos Computer Systems UUCP: {sun|pyramid|sco|amdahl|uunet}!altos86!jerry 2641 Orchard Parkway Internet: jerry@altos.com San Jose, CA 95134 Guns don't kill people, bullets do. (408) 432-6200