[net.bugs.v7] v7 swapping bug

dfh (07/27/82)

  I run a v7 system on a 11/23 with one RL drive.  ( No, this is not a
crank article).  Recently, I implememented a second drive, and decided
that swapping should occur on the second drive in order to improve
performance somewhat.  I made the appropriate changes to c.c:
  1)  I changed 'int swapdev = makedev(0,0)' to
      'int swapdev = makedev(0,1)'
  2)  I altered 'swaplo' and 'nswap' to appropriate, inconflicting
      values.
Upon booting this new kernal, the profoundly cryptic message '@U: is
not an identifier' was printed, and the single-user shell did not form.
Instead, it seemed to enter multi-user mode, since it prompted ';login:'.
I tried logging in, but I received the same error message that was
printed when the single-user shell was forming, and then was prompted
for my login again.

  The problem was that swapdev was not being opened.  The fix is in
/sys/sys/sys/main.c in iinit().  After the line:
  (*bdevsw[major(rootdev)].d_open)(rootdev, 1);
place the line:
  (*bdevsw[major(swapdev)].d_open)(swapdev, 1);


  Credit goes to Tom Truscott of Duke University for identifing the
problem immediately.  This bug seems to be one that has been carried
over from v6.

					David Hinnant
					N. C. Educational Computing Service
					(919) 549-0671
					ucbvax!decvax!duke!dfh