Kernel Definition

John F Haugh II jfh at rpp386.cactus.org
Fri May 24 22:03:11 AEST 1991


In article <1991May24.065316.27331 at thunder.mcrcim.mcgill.edu> mouse at thunder.mcrcim.mcgill.edu (der Mouse) writes:
>In article <1423 at necis.UUCP>, jjp at necis.UUCP (Jeff Phillips) writes:
>> A friend of mine is writing a paper on balanced system approach.  In
>> it he makes the assertion that "...(the UNIX operating system is) too
>> large to fit in system RAM all at once, [...]"
>
>This is true only if the term is interpreted very broadly.  All UNIXish
>systems I know of keep the kernel permanently resident; you have to
>take "the system" to include things like the shells and compilers and
>other utilities for the statement to be true.

The AIX v3 kernel is pagable.  It is divided into three "segments", as
it were.  The first is code that is only required for initialization.
The second is "pinned" code that must always be present (like the page
fault handler ;-) and the third is pagable code [ by "code" I mean
object code - that is, text and data ]

The various system tables are defined with huge sizes, and the system
just page faults in the new pages for the kernel tables as it needs
them, thus ending the dilema about creating new proc table or whateve
entries by rebuilding the system.  On a typical system the size of the
kernel is somewheres near 20MB, much of which is never even used - it
just remains off in virtual la-la land waiting to be referenced ...
-- 
John F. Haugh II        | Distribution to  | UUCP: ...!cs.utexas.edu!rpp386!jfh
Ma Bell: (512) 255-8251 | GEnie PROHIBITED :-) |  Domain: jfh at rpp386.cactus.org
"If liberals interpreted the 2nd Amendment the same way they interpret the
 rest of the Constitution, gun ownership would be mandatory."



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