rusty (10/24/82)
sorry if you're seeing this twice, i'm not sure it made
it out the first time.
(*) On a system that does no swapping and no pageouts
how much i/o activity is there on /dev/drum? How
can one determine how much activity there is?
(*) When swapping on more than one disk (via /etc/swapon)
the method used is to simply interleave the "blocks"
amongst the swap devices using modulus arithmetic.
Would it be feasable and/or advantageous to first check
the queues for the swap devices and the drive queue with
the fewest requests on it gets used?
(*) I've toyed with the idea of consolidating /usr and /;
that is instead of mounting the /usr filesystem on /
just put the /usr directories on / (but still under
the directory /usr). This implies that the / partition
would have to be increased to be able to accomodate
them.
My understanding is that the current layout is a carry
over from the v7 days of a 1 disk system on the research
machine where the user directories were directly under the
/usr directory. Given the layout of
low cylinders -> high cylinders
-------------------------------------------
| / | swap | /usr (and user files) |
-------------------------------------------
and the fact that unix on the pdp 11/45 tends to swap a
bit, this is a good layout.
All vax bsd systems I've seen have the user directories
on a separate filesystem, and a different disk than the
boot disk. These are usually rm03 or rk07 based systmes.
Thus the current layout doesn't seem to make that much
sense to me, but on the other hand it doesn't strike me
as particularly bad either. I was thinking of something
along the lines of
low cylinders -> high cylinders
-------------------------------------------
| / (and /usr) | swap |
-------------------------------------------
and possibly a third partition after the swap partition
for /tmp. Comments?