following mycroft's advice, i turned off doreallocblks. i then built
X11, which usually causes a couple of FS problems. they didn't happen,
this time.

maybe someone should investigate this further?

*** /sys/kern/vfs_cluster.c.orig	Wed Aug 24 14:37:44 1994
--- /sys/kern/vfs_cluster.c	Sat Sep 17 15:22:21 1994
***************
*** 48,58 ****
  #ifdef DEBUG
  #include <vm/vm.h>
  #include <sys/sysctl.h>
! int doreallocblks = 1;
  struct ctldebug debug13 = { "doreallocblks", &doreallocblks };
  #else
  /* XXX for cluster_write */
! #define doreallocblks 1
  #endif
  
  /*
--- 48,58 ----
  #ifdef DEBUG
  #include <vm/vm.h>
  #include <sys/sysctl.h>
! int doreallocblks = 0;
  struct ctldebug debug13 = { "doreallocblks", &doreallocblks };
  #else
  /* XXX for cluster_write */
! #define doreallocblks 0
  #endif
  
  /*
--
                    ----------------------------------------
-------------------// jason downs // downsj@CSOS.ORST.EDU //------------------
                   ----------------------------------------      JD105
		  http://www.CSOS.ORST.EDU/downsj/index.html
	       I remember the day when Sun made decent computers.