rb(4)rb(4)Namerb - IDC/RL02 disk interface
Syntax
controller idc0 at uba? csr 0175606 vector idcintr
disk rb0 at idc0 drive 0
Description
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 followed by the drive number and
then a letter, a through h, for partitions 0 through 7. The question
mark (?) character stands here for a drive number in the range 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, which provides for direct
transmission between the disk and the user's read or write buffer. A
single read or write call results in exactly one I/O operation. There‐
fore, raw I/O is considerably more efficient when many words are trans‐
mitted. The names of the raw files conventionally begin with an addi‐
tional letter r, for example,
Although RL02 disks have 256-byte sectors, the driver emulates 512-byte
sectors. Raw I/O counts should be multiples of 512 bytes (a normal
disk sector). In the same way, calls should specify a multiple of 512
bytes.
The origin and size (in 512-byte sectors) of the pseudodisks on each
drive are as follows:
RL02 partitions:
disk start length cyl
rb?a 0 15884 0-397
rb?b 15884 4520 398-510
rb?c 0 20480 0-511
rb?d 15884 4520 398-510
rb?g 0 20480 0-511
Restrictions
In raw I/O, and functions truncate file offsets to 512-byte block
boundaries; overwrites the tail of incomplete blocks. Thus, in pro‐
grams that are likely to access raw devices, and should always deal in
512-byte multiples.
Diagnostics
The following messages can appear at the console:
rb%%d%c: hard error sn%d
An unrecoverable error occurred during transfer of the specified sector
of the specified disk partition. Either the error was unrecoverable,
or a large number of retry attempts (including offset positioning and
drive recalibration) could not recover the error. Additional register
information can be gathered from the system error log file,
/usr/adm/syserr/syserr.<hostname>.
rb%d: write protected
The write protect switch was set on the drive when a write was
attempted. The write operation is not recoverable.
idc%d: lost interrupt
A timer watching the controller detected no interrupt for an extended
period while an operation was outstanding. This indicates a hardware
or software failure. The error causes a UNIBUS reset and retry of the
pending operations. If the controller continues to lose interrupts,
this error will recur a few seconds later.
FilesSee Alsodkio(4), nbuf(4), MAKEDEV(8)
VAX rb(4)
