Re: CPU Scheduling Which statement is true?
From: Bill Vermillion (bv_at_wjv.com)
Date: Thu, 20 Oct 2005 14:35:01 GMT
In article <firstname.lastname@example.org>,
>hi all, i was wondering which two of these statems are true. I am
>having trouble finding information on pinpointing my question to which
>2 statements are correct in terms of Unix.
A true false test? In Unix most answers are "it depends".
>1. BSD UNIX uses a combination of Priority scheduling and Round Robin
>scheduling, which is designed to benefit interactive processes.
>Priorities are recomputed every 2 seconds.
The documentation on this starts with Version 6 of AT&T Unix and
gets slowly changed. Those doc date to the early 1970s.
>2. Processes doing disk I/O or other important tasks have special
>priorities but can be killed by signals when necessary.
I suggest reading a book on the design of Unix. As above - "it
depends" on whether you can kill something or not.
>3. The more CPU time a process accumulates, the lower its priority
>becomes, and vice versa. BSD uses a 0.2-second quantum for the Round
Ah another "that depends"
I suggest a bit of reading and 'true/false' statements regarding
Unix >almost< all fit the 'that depends' category?
-- Bill Vermillion - bv @ wjv . com