.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)hp.4	4.1 (Berkeley) 05/15/85
.\"
.TH HP 4 5/10/81
.UC 4
.SH NAME
hp \- RP06, RM03, RM05, RM80, RP07 MASSBUS moving-head disk
.SH SYNOPSIS
disk hp0 at mba0 drive 0
.SH 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, etc.
The standard device names begin with ``hp'' 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 origin and size of the pseudo-disks on each drive are
as follows:
.PP
.nf
.ta .5i +\w'000000    'u +\w'000000    'u +\w'000000    'u +\w'000000    'u
RP06 partitions
	disk	start	length	cyls
	hp?a	0	15884	0-37
	hp?b	15884	33440	38-117
	hp?c	0	340670	0-814
	hp?g	49324	291280	118-814	
.PP
.nf
RM03 partitions
	disk	start	length	cyls
	hp?a	0	15884	0-99
	hp?b	16000	33440	100-309
	hp?c	0	131680	0-822
	hp?g	49600	81984	310-822
.PP
.nf
RM05 partitions
	disk	start	length	cyls
	hp?a	0	15884	0-26
	hp?b	16416	33440	27-81
	hp?c	0	500384	0-822
	hp?d	341696	15884	562-588
	hp?e	358112	55936	589-680
	hp?f	414048	86240	681-822
	hp?g	341696	158592	562-822
	hp?h	49856	291346	82-561
.PP
.nf
RM80 partitions
	disk	start	length	cyls
	hp?a	0	15884	0-36
	hp?b	16058	33440	37-114
	hp?c	0	242606	0-558
	hp?g	49910	82080	115-304
	hp?h	132370	110143	305-558
.PP
.nf
RP07 partitions
	disk	start	length	cyls
	hp?a	0	15884	0-9
	hp?b	16000	64000	10-49
	hp?c	0	1008000	0-629
	hp?d	528000	15884	330-339
	hp?e	544000	258000	340-499
	hp?f	800000	207850	500-629
	hp?g	528000	479850	330-629
	hp?h	80000	448000	50-329
.fi
.DT
.PP
It is unwise for all of these files to be present in one installation,
since there is overlap in addresses and protection becomes
a sticky matter.
The hp?a partition is normally used for the root file system,
the hp?b partition as a paging area,
and the hp?c partition for pack-pack copying (it maps the entire disk).
On rp06's and rm03's the hp?g partition maps the rest of the pack.
On rm80's, rm05's and rp07's, both hp?g and hp?h are used to map the
remaining cylinders.
.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 FILES
.ta 2i
/dev/hp[0-7][a-h]	block files
.br
/dev/rhp[0-7][a-h]	raw files
.SH SEE ALSO
hk(4), up(4)
.SH DIAGNOSTICS
\fBhp%d%c: hard error sn%d mbsr=%b er1=%b er2=%b\fR.  An unrecoverable
error occured during transfer of the specified sector of the specified
disk partition.  The MASSBUS status register is printed in hexadecimal and
with the error bits decoded if any error bits other than MBEXC and DTABT
are set.  In any case the contents of the two error registers are also printed
in octal and symbolically with bits decoded.
(Note that er2 is what old rp06 manuals would call er3; the terminology
is that of the rm disks).
The error was either unrecoverable, or a large number of retry attempts
(including offset positioning and drive recalibration) could not
recover the error.
.PP
\fBhp%d: write locked\fR.  The write protect switch was set on the drive
when a write was attempted.  The write operation is not recoverable.
.PP
\fBhp%d: not ready\fR.  The drive was spun down or off line when it was
accessed.  The i/o operation is not recoverable.
.PP
\fBhp%d%c: soft ecc sn%d\fR.  A recoverable ECC error occurred on the
specified sector of 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 occuring should be checked to see
if certain cylinders on the pack, spots on the carriage of the drive
or heads are indicated.
.SH BUGS
In raw I/O
.I read
and
.IR write (2)
truncate file offsets to 512-byte block boundaries,
and
.I write
scribbles on the tail of incomplete blocks.
Thus,
in programs that are likely to access raw devices,
.I read, write
and
.IR lseek (2)
should always deal in 512-byte multiples.
.PP
DEC-standard error logging should be supported.
.PP
Bad block forwarding is not yet supported on RP06's.
.PP
A program to analyze the logged error information (even in its
present reduced form) is needed.
.PP
The partition tables for the file systems should be read off of each
pack, as they are never quite what any single installation would prefer,
and this would make packs more portable.