RL(4)

NAME
rl - RL-11/RL01, RL02 moving-head disk

SYNOPSIS
/sys/conf/SYSTEM:
	NRL	rl_drives	# RL01/02
/etc/dtab:
	#Name	Unit#	Addr	Vector	Br	Handler(s)		# Comments
	rl	?	174400	160	5	rlintr		# rl-01/02
major device number(s):
	raw: 16
	block: 7
minor device encoding:
	bits 0007 specify partition of RL drive
	bits 0070 specify RL drive

DESCRIPTION
The block files access the disk via the system's normal buffering mechanism and may 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 and therefore raw I/O is considerably more efficient when many words are transmitted. The names of the raw files conventionally begin with an extra `r.'

In raw I/O the buffer must begin on a word (even) boundary, and counts should be a multiple of 512 bytes (a disk sector). Likewise seek calls should specify a multiple of 512 bytes.

DISK SUPPORT
The RL01 drives are each 10240 blocks long and the RL02 drives are 20480 blocks long.

On a RL02 there is room for a full sized root ('a') partition and a reasonable sized swap ('b') partition. The RL01 can only (realistically) have a single 5mb partition.

FILES
/dev/rl[0-3][a-h]    block files
/dev/rrl[0-3][a-h]    raw files
/dev/MAKEDEV    script to create special files
/dev/MAKEDEV.local    script to localize special files

SEE ALSO
hk(4), ra(4), ram(4), rk(4), rp(4), rx(4), si(4), xp(4), dtab(5), autoconfig(8)

DIAGNOSTICS
rl%d: hard error sn%d cs=%b da=%b. An unrecoverable error occurred during transfer of the specified sector of the specified disk. The contents of the two error registers are also printed in octal and symbolically with bits decoded. The error was either unrecoverable, or a large number of retry attempts could not recover the error.

rl%d: hard error sn%d mp=%b da=%b. An unrecoverable drive error occured during transfer of the specified sector of the specified disk. The contents of the two error registers are also printed in octal and symbolically with bits decoded. The error was either unrecoverable, or a large number of retry attempts could not recover the error.

rl%d: write locked. The write protect switch was set on the drive when a write was attempted. The write operation is not recoverable.

rl%d: can't get status. A ``get status'' command on the specified drive failed. The error is unrecoverable.

BUGS
In raw I/O read and write(2) truncate file offsets to 512-byte block boundaries, and write scribbles on the tail of incomplete blocks. Thus, in programs that are likely to access raw devices, read, write and lseek(2) should always deal in 512-byte multiples.

DEC-standard error logging should be supported.

A program to analyze the logged error information (even in its present reduced form) is needed.