.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)uda.4	6.2 (Berkeley) 5/16/86
.\"
.TH UDA 4 "May 16, 1986"
.UC 4
.SH NAME
uda \- UDA-50 disk controller interface
.SH SYNOPSIS
.B "controller uda0 at uba0 csr 0172150 vector udintr"
.br
.B "disk ra0 at uda0 drive 0"
.SH DESCRIPTION
This is a driver for the DEC UDA-50 disk controller
and for other compatible controllers.
The UDA-50 communicates with the host through a packet
oriented protocol termed the Mass Storage Control Protocol (MSCP).
Consult the file
.RI < vax/mscp.h >
for a detailed description of this protocol.
.PP
Files with minor device numbers 0 through 7 refer to various portions
of drive 0;
minor devices 8 through 15 refer to drive 1, etc.
The standard device names begin with ``ra'' followed by
the drive number and then a letter a-h for partitions 0-7 respectively.
The character ? stands here for a drive number in the range 0-7.
.PP
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.'
.PP
In raw I/O counts should be a multiple of 512 bytes (a disk sector).
Likewise
.I seek
calls should specify a multiple of 512 bytes.
.SH "DISK SUPPORT"
This driver configures the drive type of each drive
when it is first opened.
A partition table in the driver is required for each type of disk.
The origin and size (in sectors) of the pseudo-disks
on each drive are shown below.
Not all partitions begin on
cylinder boundaries, as on other drives, because previous drivers
used one partition table for all drive types.
Variants of the partition tables are common;
check the driver and the file
.IR /etc/disktab ( disktab (5))
for other possibilities.
.PP
.nf
.ta .5i +\w'000000    'u +\w'000000    'u +\w'000000    'u +\w'000000    'u
.PP
RC25 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	15884	10032
	ra?c	0	50902
	ra?g	25916	24986
RD52 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	15884	9766
	ra?c	0	60480
	ra?g	25650	34830
RD53 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	15884	33440
	ra?c	0	138672
	ra?g	49324	89348
	ra?h	15884	122788
RA60 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	15884	33440
	ra?c	0	400176
	ra?d	49324	82080	same as 4.2BSD ra?g
	ra?e	131404	268772	same as 4.2BSD ra?h
	ra?f	49324	350852
	ra?g	242606	157570
	ra?h	49324	193282
.PP
RA80 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	15884	33440
	ra?c	0	242606
	ra?e	49324	193282	same as old Berkeley ra?g
	ra?f	49324	82080	same as 4.2BSD ra?g
	ra?g	49910	192696
	ra?h	131404	111202	same as 4.2BSD
.PP
RA81 partitions
	disk	start	length
	ra?a	0	15884
	ra?b	16422	66880
	ra?c	0	891072
	ra?d	375564	15884
	ra?e	391986	307200
	ra?f	699720	191352
	ra?g	375564	515508
	ra?h	83538	291346
.PP
RA81 partitions with 4.2BSD-compatible partitions
	disk	start	length
	ra?a	0	15884
	ra?b	16422	66880
	ra?c	0	891072
	ra?d	49324	82080	same as 4.2BSD ra?g
	ra?e	131404	759668	same as 4.2BSD ra?h
	ra?f	412490	478582	same as 4.2BSD ra?f
	ra?g	375564	515508
	ra?h	83538	291346
.DT
.fi
.PP
The ra?a partition is normally used for the root file system,
the ra?b partition as a paging area,
and the ra?c partition for pack-pack copying (it maps the entire disk).
.SH FILES
/dev/ra[0-9][a-f]
.br
/dev/rra[0-9][a-f]
.SH DIAGNOSTICS
.BR "uda: ubinfo %x" .
(VAX 11/750 only.)
When allocating UNIBUS resources, the driver found it already
had resources previously allocated.  This indicates a bug in
the driver.
.PP
.BR "udasa %o, state %d" .
(Additional status information given after a hard i/o error.)
The values of the UDA-50 status register and the internal
driver state are printed.
.PP
.BR "uda%d: random interrupt ignored" .
An unexpected interrupt was received (e.g. when no i/o was
pending).  The interrupt is ignored.
.PP
.BR "uda%d: interrupt in unknown state %d ignored" .
An interrupt was received when the driver was in an unknown
internal state.  Indicates a hardware problem or a driver bug.
.PP
.BR "uda%d: fatal error (%o)" .
The UDA-50 indicated a ``fatal error'' in the status returned
to the host.  The contents of the status register are displayed.
.PP
.BR OFFLINE .
(Additional status information given after a hard i/o error.)
A hard i/o error occurred because the drive was not on-line.
.PP
.BR "status %o" .
(Additional status information given after a hard i/o error.)
The status information returned from the UDA-50 is tacked onto
the end of the hard error message printed on the console.
.PP
.BR "uda: unknown packet" .
An MSCP packet of unknown type was received from the UDA-50.
Check the cabling to the controller.
.PP
The following errors are interpretations of MSCP error messages
returned by the UDA-50 to the host.
.PP
.BR "uda%d: %s error, controller error, event 0%o" .
.PP
.BR "uda%d: %s error, host memory access error, event 0%o, addr 0%o" .
.PP
.BR "uda%d: %s error, disk transfer error, unit %d" .
.PP
.BR "uda%d: %s error, SDI error, unit %d, event 0%o" .
.PP
.BR "uda%d: %s error, small disk error, unit %d, event 0%o, cyl %d" .
.PP
.BR "uda%d: %s error, unknown error, unit %d, format 0%o, event 0%o" .
.SH BUGS
The partition tables attempt to combine compatibility
with previous drivers and functionality; this is impossible.
The best solution would be to read the partition tables
off the drive.