dillon@CORY.BERKELEY.EDU (Matt Dillon) (09/25/86)
With UNIX, the OS isn't a process, it's GOD. On the Amiga, the OS is a bunch of processes. When you run a normal program at a priority higher than that of the OS, you can get into lockout problems. Also, unless you have any other tasks running smaller than 0, it doesn't make a whit of difference to run task x at -1 or -100. Same goes for higher priority tasks.. if the highest priority task in the system is running at 20, then there is no difference between task x running at 21 or 100. -Matt
rick@mips.UUCP (Rick Frazier) (09/26/86)
> With UNIX, the OS isn't a process, it's GOD. On the Amiga, the OS > is a bunch of processes. When you run a normal program at a priority > higher than that of the OS, you can get into lockout problems. Also, unless > you have any other tasks running smaller than 0, it doesn't make a whit > of difference to run task x at -1 or -100. Same goes for higher priority > tasks.. if the highest priority task in the system is running at 20, > then there is no difference between task x running at 21 or 100. > -Matt Well, yes and no.... In UNIX, if you are a "super user" with "root" accesses and powers, you CAN get yourself into the same sort of trouble...... You wouldn't want to try it, but setting the priority of a process high enough under UNIX can "lock out" such processes as the disk paging daemons, etc, which will effectively lock up your machine. (IE: If your process has a higher priority than the daemons that must service it, they may never get a chance to do so, unless the process breaks or is stopped externally). By the way, UNIX priorities are higher at the negative end of the scale and lower at the positive end of the scale, so someone that sets his process to 15 instead of 0 really decreases the relative amount of processing time allotted, relative to other 0-level processes. I just run the Amiga as if it were a single-user unix-style machine, and have never gone that crazy with higher priority processes. I believe you have brought up an important point for those not so familiar with the whole priority world...that of relative priority. Indeed, it does not matter that a process is a 20 or 100, as long as everyone else is less than 20. All too few novices realize that the priority is not a DIRECT "percentage of processing power" that's being set, and really a RELATIVE priority. -- --Rick Frazier-- DISCLAIMER: The above is individual opinion (the result of my imperfect recall of facts, real or imagined) in no way representing anyone else. UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!rick DDD: 408-720-1700 x278