mwm@VIOLET.BERKELEY.EDU.UUCP (02/10/87)
------- Forwarded Message From: blarson@castor.usc.edu (Bob Larson) Newsgroups: mod.computers.68k Subject: Re: Minix to the 68k? Date: 8 Feb 87 08:11:15 GMT Reply-To: blarson@castor.usc.edu.UUCP (Bob Larson) Organization: USC AIS, Los Angeles Lines: 23 In article <8702070057.AA17890@amdcad.AMD.COM> bandy@amdcad.UUCP (Andy Beals) writes: >Given that I'm a little shy on information about #3, I'd like to ask the >Amiga gurus here how the Amiga manages to do multitasking. (for that matter, >how does OS9 mangage it?) All Os9 code (except for some system dependent stuff like the boot code) is position indepentent and sharable. When a program is started, if it is not already in memory, (due to special request or another user using it) it is loaded into avalable memory. Data areas are allocated seperatly. Once memory has been allocated, it is not released until it is no longer in use. (Relocation does not occur durring execution.) This allows return addresses, etc. to be pushed on the stack in the normal manner. Yes, this scheme does have the clasical "fragmentation" problem, and does limit your processes to physical memory, but a few extra kilobytes of memory is probably cheaper than a MMU. (This refers only to level I os9. Level II, such as will soon be released for the coco 3, does use an MMU.) - -- Bob Larson Arpa: Blarson@Usc-Eclb.Arpa Uucp: (several backbone sites)!sdcrdcf!usc-oberon!castor.usc.edu!blarson seismo!cit-vax!usc-oberon!castor.usc.edu!blarson ------- End of Forwarded Message