RL(4)		    UNIX Programmer's Manual		    RL(4)



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

SYNOPSIS
     /sys/conf/SYSTEM:
	  NRL  _r_l__d_r_i_v_e_s # 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 there-
     fore 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 sec-
     tor).  Likewise _s_e_e_k 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') parti-
     tion 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)




Printed 11/26/99	 August 20, 1987			1






RL(4)		    UNIX Programmer's Manual		    RL(4)



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 _r_e_a_d and _w_r_i_t_e(2) truncate file offsets to 512-
     byte block boundaries, and _w_r_i_t_e scribbles on the tail of
     incomplete blocks.  Thus, in programs that are likely to
     access raw devices, _r_e_a_d, _w_r_i_t_e and _l_s_e_e_k(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.






















Printed 11/26/99	 August 20, 1987			2