mcm@ncsu.UUCP (10/13/83)
I found a bug awhile ago in the stand-alone hp driver. This
applies to systems runing 4.1 BSD with RP07 disk drives.
It might apply to other systems with RP07 drives, I've never
checked.
Anyway, the symptom is that the drive won't respond correctly after the
drive has been powered down. A message is printed about a disk format
error. The format error doesn't go away until the drive is checked
with a DEC diagnostic.
The problem is that the RP07 keeps the volume valid bit set in the
controller all the time. Dec must have thought that since the RP07
is a fixed disk, the volume must be valid all the time. The code
in the hpstrategy routine checks the volume valid bit, and if it
is clear, sets the FMT_22 bit, thus forcing the drive to the correct
format.
A simple solution is to remove the check for the volume valid
bit, and do the body of the 'if' all the time. This will not
cause any problem, just making disk accesses slightly slower.
We've been using the code since April.
I'm enclosing a diff -c listing below.
Mike Mitchell
duke!mcnc!ncsu!mcm
THIS IS IN THE STANDALONE HP.C ONLY!!!!!!!!!!!!!!!!!!!!!
*** /sys/stand/hp.c Mar 22 16:59:26 1981
--- /sys/stand/hp.org.c Apr 25 14:37:00 1983
***************
*** 77,83
struct hpst *st = &hpst[hp_type[unit]];
int cn, tn, sn;
! if ((hpaddr->hpds & HPDS_VV) == 0) {
hpaddr->hpcs1 = HP_DCLR|HP_GO;
hpaddr->hpcs1 = HP_PRESET|HP_GO;
hpaddr->hpof = HPOF_FMT22;
--- 77,89 -----
struct hpst *st = &hpst[hp_type[unit]];
int cn, tn, sn;
! /*
! * Commented out the if statment (not the body) so that it will
! * re-init the drive every time.
! * 4/25/83 Mike Mitchell
! *
! * if ((hpaddr->hpds & HPDS_VV) == 0) {
! */
hpaddr->hpcs1 = HP_DCLR|HP_GO;
hpaddr->hpcs1 = HP_PRESET|HP_GO;
hpaddr->hpof = HPOF_FMT22;
***************
*** 81,87
hpaddr->hpcs1 = HP_DCLR|HP_GO;
hpaddr->hpcs1 = HP_PRESET|HP_GO;
hpaddr->hpof = HPOF_FMT22;
! }
cn = bn/st->nspc;
sn = bn%st->nspc;
tn = sn/st->nsect;
--- 87,95 -----
hpaddr->hpcs1 = HP_DCLR|HP_GO;
hpaddr->hpcs1 = HP_PRESET|HP_GO;
hpaddr->hpof = HPOF_FMT22;
! /*
! * }
! */
cn = bn/st->nspc;
sn = bn%st->nspc;
tn = sn/st->nsect;