sdc(4)sdc(4)Namesdc - RD31, RD32, RD53, RD54, RX33, RX23 Small VAX disk interface
Syntax
controller sdc0 at uba0 csr 0x200c0000 vector sdintr
disk rd0 at sdc0 drive 0
disk rd1 at sdc0 drive 1
disk rx2 at sdc0 drive 2
Description
This is a driver for the Digital Small VAX disk controller. This disk
controller is used by both the workstation and multiuser configurations
of the busless Small VAX processor. This controller also supports the
RX23 floppy disk drive in the VAXstation 3100 model 30 processor.
The SDC driver uses the same disk format as the RQDX3 controller. Win‐
chester disks formatted by the small VAX controller are compatible with
RQDX3 formatted disks, but not with RQDX1 and RQDX2 formatted disks.
The SDC driver implements dynamic bad block replacement in the same
manner as the RQDX3 controller.
Files with minor device numbers 0 through 7 refer to various portions
of drive 0; minor devices 8 through 15 refer to drive 1, and so forth.
The standard device names begin with rd, for Winchester disk drives 0
and 1 and rx, for the diskette drive 2 followed by the drive number and
then a letter, a through h, for partitions 0 through 7.
The block files access the disk by the system's normal buffering mecha‐
nism and can be read and written, without regard to physical disk
records. There is also a raw interface that provides for direct trans‐
mission between the disk and the user's read or write buffer. One read
or write call results in one I/O operation, so raw I/O is considerably
more efficient when many words are transmitted. The names of the raw
files conventionally begin with an additional letter r, for example,
In raw I/O, counts should be a multiple of 512 bytes (a disk sector).
In the same way, calls should specify a multiple of 512 bytes.
Disk Support
The SDC driver handles RD31, RD32, RD53, and RD54 Winchester disk
drives on drives 0 and 1 and the RX33/RX23 floppy disk drive on drive
2. The RX33 drive reads and writes both single-density (400 Kbytes)
RX50 floppy diskettes and double-density double-sided (1200 Kbytes)
RX33 diskettes. The RX23 drive reads and writes high density (18 sec‐
tors per track) RX23 floppy diskettes and reads double density (9 sec‐
tors per track) RX23 floppy diskettes. Drive types are recognized in
the autoconfiguration process. For constructing file systems, the par‐
tition sizes are required. Partition sizes are the same as those sup‐
ported by the MSCP driver, Partition sizes can be queried or changed by
The rd?a partition is usually used for the root file system, the rd?b
partition as a paging area, and the rd?g partition for the usr file
system.
Diagnostics
The following messages are printed at the console and written to the
system error log file, /usr/adm/syserr/syserr.<hostname>.
sd%d:HARD_ERR: cannot read XBN
The driver cannot read the format information from the disk during
autoconfiguration. The disk may not be formatted properly.
sd%d:HARD_ERR: CANNOT RECOVER FROM PREVIOUS BBR
Bad block replacement was interrupted in the middle when the system was
last halted. The driver cannot successfully complete the bad block
replacement. Try to recover all the data from the disk and reformat
it. Refer to the Guide to System Configuration File Maintenance for
additional information.
sd%d:HARD_ERR: Drive select failed
The driver cannot select the specified drive for doing I/O. Make sure
the drive is on line.
sd%d:HARD_ERR: Invalid cylinder: %d
The driver tries I/O on a cylinder outside the valid range for the type
of disk on the drive. This is a fatal error caused by the driver and
should not happen.
sd%d:HARD_ERR: Invalid head:%d
The driver tries I/O on a head outside the valid range for the type of
disk on the drive. This is a fatal error caused by the driver and
should not happen.
sd%d:HARD_ERR: Forced Error Modifier set LBN %d
The forced error bit is set on the specified block. The block was
found to be bad and has been replaced with a good block, but the data
in the block is bad. Writing new data into this block will clear the
forced error bit. Refer to the Guide to System Configuration File
Maintenance for additional information.
sd%d:HARD_ERR: compare error
The driver received a compare error for the drive from the controller.
This should be seen only for the floppy drive. For hard disks, the bad
block will get replaced.
sd%d:HARD_ERR: eccerror
The driver received an ECC error for the drive from the controller.
sd%d:HARD_ERR: syncerr
The driver received a sync error for the drive from the controller. If
it is the floppy drive, reinsert the floppy and repeat the command.
sd%d:HARD_ERR: bad sector
The controller detected the sector to be bad from the sector's ID
field. This message should appear only for the floppy drive. For hard
disks, the bad block will get replaced.
sd%d:HARD_ERR: WRITE FAULT
This is due to an internal error in the drive, such as an improper sup‐
ply voltage. This message should appear only for hard disk drives.
The following messages are written to the system error file,
/usr/adm/syserr/syserr.<hostname>, but not printed at the console..
sd:SOFT_ERR: stray interrupt
An unexpected interrupt was received (for example, when no I/O was
pending). The interrupt is ignored.
sd:SOFT_ERR: No valid buffer
An interrupt was received when the driver was not ready to receive one.
The interrupt is ignored. This should rarely happen.
sd%d:SOFT_ERR: Command not yet implemented thru interrupt, command =
%c"
An interrupt was received for the command. This should not happen.
The interrupt is ignored.
sd%d:SOFT_ERR: Unknown error type, UDC_CSTAT = %o, UDC_DSTAT = %o,
DKC_STAT = %o"
The error type indicated by the controller for the last I/O is not any
of the common ones. An I/O error is generated.
FilesSee Alsodkio(4), nbuf(4), ra(4), rd(4), rx(4), chpt(8), uerf(8)
VAX sdc(4)