.\" SCCSID: @(#)rk.4	8.1	9/11/90.TH rk 4 VAX.SH Namerk \- RK711/RK07 disk interface.SH Syntax.B "controller hk0 at uba? csr 0177440 vector rkintr".br.B "disk rk0 at hk0 drive 0".SH Description.NXS "rk interface" "RK711 disk interface".NXS "rk interface" "RK07 disk interface".NXS "hk interface" "RK711 disk interface".NXS "hk interface" "RK07 disk interface".NXR "RK711 disk interface".NXR "RK07 disk interface"Files with minor device numbers 0 through 7 refer to various portionsof drive 0;minor devices 8 through 15 refer to drive 1, and so forth.The standard device names begin with ``hk'' followed bythe drive number and then a letter, a through h, forpartitions 0 through 7.The question mark (?) character stands here for a drive number in the range0 through 7..PPThe block files access the disk using the system's normalbuffering mechanism and can be read and written, without regard tophysical disk records.	There is also a raw interfacethat provides for direct transmission between the diskand the user's read or write buffer.A single read or write call results in exactly one I/O operation.Therefore, raw I/O is considerably more efficient whenmany words are transmitted.  The names of the raw filesconventionally begin with an additional letter r, for example,.PN rrx2c ..PPIn raw I/O, counts should be multiples of 512 bytes (a disk sector).In the same way,.PN seekcalls should specify a multiple of 512 bytes..PPThe origin and size (in sectors) of thepseudodisks on each drive are as follows:.PP.NXR "RK07 disk" "pseudodisk partitions".nf.ta .5i +\w'000000    'u +\w'000000    'u +\w'000000	'uRK07 partitions:	disk	start	length	cyl	rk?a	0	15884	0-240	rk?b	15906	10032	241-392	rk?c	0	53790	0-814	rk?g	26004	27786	393-813.DT.fi.PP.SH RestrictionsIn raw I/O,.PN readand.PN writefunctions truncate file offsets to 512-byte block boundaries;.PN writeoverwrites the tail of incomplete blocks.Thus,in programs that are likely to access raw devices,.MS read 2 ,.MS write 2 ,and.MS lseek 2should always deal in 512-byte multiples..SH DiagnosticsThe following messages are printed at the console:.PP.B "rk%d%c: hard error sn%d".brAn unrecoverable error occurred during transfer of thespecified 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 notrecover the error.  Additional register information can begathered from the system error log file,\f(CW/usr/adm/syserr/syserr.\fI<hostname>\fR..PP.B "rk%d: write locked".brThe write protect switch was set on the drive whena write was attempted.The write operation is not recoverable..PP.B "rk%d: not ready".brThe drive was spun down or off line when it wasaccessed.The I/O operation is not recoverable..PP.B "rk%d: not ready (came back!)".brThe drive was not ready.But, after printing this message (which takes a fractionof a second), it was ready.The operation is recovered, if no further errors occur..PP.B "hk%d: lost interrupt".brA timer watching the controller detected no interrupt foran extended period while an operation was outstanding.This indicates a hardware or software failure.Spinning down drives while they are being accessed causes thiserror to occur.The error causes a UNIBUS reset and retry of the pending operations.If the controller continues to lose interrupts, this error will recura few seconds later..PP.B "rk%d%c: soft ecc sn%d".brThis message is written to the system error log file only.A recoverable ECC error occurred on the specified sectorin the specified disk partition.This happens normally a few times a week.If it happens more frequently than this,the sectors where the errors are occurring should be checked to seeif the same physical location on the disk pack is causing the error. Errors in the same area on the disk pack indicate the pack is going bad.  Random errors can be caused by a pack going bad or a pending hardware problem.  .SH Files.PN /dev/rk???.br.PN /dev/rrk???.SH See Alsodkio(4), nbuf(4), MAKEDEV(8), uerf(8)