swap

[Piercarlo Grandi]

In article <368 at trevan.UUCP> trevor at trevan.UUCP (trevor) writes:
    
    	The distribution Microport V/AT has a swap device witha major
    number of 1 and minor of 198. This is infact the mem device.

The kernel on the floppy uses a ramdisk for swapping so that the bootable
floppy can be read only. You absolutely don't want a hard disk rooted system
to continue swapping to the ramdisk. Indeed you may want to remove the
ramdisk from the hard disk kernel configuration (in favour of larger buffer
chaches).

    I suspect that it is redundant as the swap devices are also contained in
    the dsk and rdsk directories.

The kernel only obeys the "swapdev" definition given when it is built; it
completely ignores the /dev*swap device files. The /dev*swap device files are
used by "ps" (mainly) to read the u-area/stack of swapped out processes. It
is the system administrator's responsibility that the /dev/*swap devices map
onto the same partition indicated in the "swapdev" variable definition; if
they are not, "ps" (and some other commands) will just report incorrect
things.
-- 
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk at nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg at cs.aber.ac.uk