ra.4

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)ra.4	2.1	3/10/87
.TH ra 4
.SH Name
ra \- MSCP disk interface
.SH Syntax
.B For UNIBUS, Q-bus:
.RS 3
.br
.B "controller uda0 at uba?"
.br
.B "controller uq0 at uda0 csr 0172150 vector uqintr"
.br
.B "disk ra0 at uq0 drive 0"
.RE
.PP
.B For VAX BI:
.RS 3
.br
.B "controller kdb0 at vaxbi0 node 4"
.br
.B "controller uq0 at kdb0 vector uqintr"
.br
.B "disk ra0 at uq0 drive 0"
.br
.B "controller bvpssp0 at aio1 vector bvpsspintr"
.br
.B "disk ra0 at bvpssp0 drive 0"
.RE
.PP
.B For MSI Bus:
.br
.RS 3
.B "adapter msi0 at nexus?"
.br
.B "controller dssc0 at msi0 msinode 0"
.br
.B "disk ra0 at dssc0 drive 3"
.RE
.PP
.B For VAX CI/HSC:
.br
.RS 3
.B "adapter ci0 at nexus?"
.br
.B "adapter ci0 at vaxbi? node?"
.br
.B "controller hsc0 at ci0 cinode 6"
.br
.B "disk ra0 at hsc0 drive 3"
.RE
.SH Description
.NXS "ra interface" "MSCP disk interface"
.NXB "MSCP disk interface"
.NXS "uda interface" "MSCP disk interface"
Prior to Version 2.0, this device was referenced by 
.MS uda 4 .
.PP
This is a driver for all DIGITAL MSCP disk controllers.
All controllers communicate with the host through a packet-oriented 
protocol termed the Mass Storage Control Protocol (MSCP).
.PP
The following rules are used to determine the major and minor numbers that
are associated with an 
.PN ra
type disk.  There is a range of major numbers used to represent  
.PN ra 
disks.  Each major number represents 32 disks.  For this reason, the first
major number associated with 
.PN ra
disks represents logical unit number 0 through logical unit number 31.
Similarly the second major number represents logical unit number 32 through
logical unit number 63. 
The minor number is used to represent both the logical unit
number and partition.  A disk partition refers to a designated portion
of the physical disk.
To accomplish this, the 8-bit minor number is broken up
into two parts.  The low three bits of the minor number specify a disk
partition.  These three bits allow for the naming of eight partitions.  The
partitions are named a,b,c,d,e,f,g and h.  The upper five bits of the minor
number specify the logical unit number within a group of 32 disks.
.PP
The device special file names associated with 
.PN ra 
disks are based on 
the following conventions, which are closely associated with
the minor number assigned to the disk. 
The standard device names begin with
.PN ra 
for the block special file and
.PN rra 
for the raw (character) special file.
Following the
.PN ra
is the logical unit number and then a letter, a through h, to represent
the partition.  Throughout this reference page,
the question mark (?) character represents
the logical unit number in the name of the device special file.  For example
ra?b could represent ra0b, ra1b, and so on.
.PP
The following examples illustrate how the logical unit number is
calculated given the major and minor number of an 
.PN ra
disk.  For the device special file rra6a, the major number is 60 and the
minor number is 48.  The partition is represented by the low 3 bits of the 
number 48.  The low 3 bits  will be 0 which specifies the ``a''
partition.  The upper 5 bits of 48 specifies the number 6.  
The major number is 60.  Because 60 is the base major number, it 
represents the first group of 32 disks.  For this
reason, there is no need to adjust the unit number for a high order grouping.
Putting all these pieces together reveals that the major/minor pair 60/48
refers to the ``a'' partition of logical unit 6.  As another example, 
the following computation determines
the logical unit number corresponding to the major/minor
pair 62,49.  The low 3 bits of the minor number gives the number 1, which
is the ``b'' partition.  
The upper 5 bits of the minor number gives the number 6.
The major number is 62.  Subtracting 62 from the base major number of 60 gives
a value of 2.  This means that 2 groups of 32 disks preceed the unit in
question.  For this reason, the logical unit number is as follows:
(2 * 32) + 6 = 70.  The figure 6 is from the minor number. 
Therefore, the major/minor pair 62,49 refers to the ``b''
partition of logical unit number 70, or rra70b.
.PP
The disk can be accessed through either the block special file or the 
character special file.  The block special file accesses the disk using
the file system's normal buffering mechanism.  Reads and writes to the block
special file can specify any size.  This avoids the need to limit data 
transfers to the size of physical disk records and to calculate offsets
within disk records.
The file system may break up large read and write requests into smaller 
fixed size transfers to the disk.
.PP
The character special file provides a raw interface which allows for
direct transmission between the disk and the user's read or write buffer.
In contrast to the block special file, reads and writes to the raw interface
must be done on full sectors only.  
For this reason,
in raw I/O, counts should be multiples of 512 bytes (a disk sector).
In the same way,
.PN seek
calls should specify a multiple of 512 bytes.
A single read or write to the raw interface results in 
exactly one I/O operation,
consequently raw I/O may be considerably more efficient for large transfers.
Multiply buffered I/O operations are
possible to any raw MSCP device. (See 
.MS nbuf 4
for more information.)
.SH Disk Support
.NXR "MSCP disk interface" "disk support"
This driver handles all disk drives that may be connected to an MSCP-based
controller.  Consult the 
.I "ULTRIX Software Product Description" 
to determine which controllers
are supported for which CPU types and hardware configurations.
.PP
The starting location and length (in 512-byte sectors) 
of the disk partitions of each
drive are shown in the following table.
Partition sizes can be changed
by 
.MS chpt 8 .
For further information, see 
.MS dkio 4 .
.PP
.NXB "MSCP disk interface" "partition tables"
.nf
.ta .5i +\w'000000    'u +\w'000000    'u +\w'000000	'u +\w'000000	 'u
.PP
.B "RA60 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	50160
	ra?c	0	400176
	ra?d	24298	52416
	ra?e	295344	52416
	ra?f	347760	52415
	ra?g	82928	160000
	ra?h	24928	157247
	ra?h	281805	265236
.PP
.B "RA70 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	66690
	ra?c	0	547042
	ra?d	0	99458	
	ra?e	0	281805
	ra?f	99458	447583
	ra?g	99458	182347
.PP
.B "RA71 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	131072
	ra?c	0	1367310
	ra?d	778240	204800
	ra?e	983040	204800
	ra?f	1187840	179470
	ra?g	163840	614400
	ra?h	778240	589070
.PP
.B "RA72 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	190464
	ra?c	0	1953300
	ra?d	1144832	299008
	ra?e	1443840	299008
	ra?f	1742848	210452
	ra?g	223232	921600
	ra?h	1144832	808468
.PP
.B "RA80 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	50160
	ra?c	0	237212
	ra?d	82928	51428
	ra?e	134356	51428
	ra?f	185784	51428
	ra?g	82928	154284
	ra?h	0	0
.PP
.B "RA81 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	66690
	ra?c	0	891072
	ra?d	323840	210538
	ra?e	46996	210538
	ra?f	680534	210538
	ra?g	99458	160000
	ra?h	259458	631614
.PP
.B "RA82 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	66690
	ra?c	0	1216665
	ra?d	99458	220096
	ra?e	319554	219735
	ra?f	539289	437760
	ra?g	99458	877591
	ra?h	977049	239616
.PP
.B "RA90 partitions"
	disk	start	length
.sp
	ra?a	0	32768	
	ra?b	32768	127072	
	ra?c	0	2409680
	ra?d	159840	420197	
	ra?e	580037	420197
	ra?f	1000234	840393
	ra?g	159840	1680787
	ra?h	1840627	535526
.PP
.B "RA92 partitions"
	disk    start   length
	ra?a    0       32768
	ra?b    32768   127072
	ra?c    0       2940951
	ra?d    159840  420197
	ra?e    580037  420197
	ra?f    1000234 840393
	ra?g    159840  1680787
	ra?h    1840627 1100324
.PP
.B "RD31 partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	10024
	ra?c	0	41560
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	25908	15652
	ra?h	0	0
.PP
.B "RD32 partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	15625
	ra?c	0	83236
	ra?d	31509	25863
	ra?e	57372	25864
	ra?f	0	0
	ra?g	31509	51727
	ra?h	0	0
.PP
.B "RD51 partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	5716
	ra?c	0	21600
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	0	0
	ra?h	0	0
.PP
.B "RD52 partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	9766
	ra?c	0	60480
	ra?d	0	0
	ra?e	0	50714
	ra?f	50714	9766  
	ra?g	25650	34830
	ra?h	15884	44596
.PP
.B "RD53 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	50160
	ra?c	0	138672
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	82928	55744
	ra?h	32768	105904
.PP
.B "RD54 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	50160
	ra?c	0	311200
	ra?d	82928	130938
	ra?e	213866	97334
	ra?f	0	0
	ra?g	82928	228272
	ra?h	0	0
.PP
.B "RF30 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	50160
	ra?c	0	293040
	ra?d	82928	130938
	ra?e	213866	79173
	ra?f	0	0
	ra?g	82928	210111
	ra?h	0	0
.PP
.B "RF31 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	66690
	ra?c	0	744400
	ra?d	0	99458
	ra?e	0	281805
	ra?f	99458	644942
	ra?g	99458	182347
	ra?h	281805	462595
.PP
.B "RF71 partitions"
	disk	start	length
.sp
	ra?a	0	32768
	ra?b	32768	66690
	ra?c	0	781440
	ra?d	0	99458
	ra?e	0	281805
	ra?f	99458	681982
	ra?g	99458	182347
	ra?h	281805	499635
.PP
.B "RRD40 (read only) partitions"
	disk	start	length
.sp
	ra?a	0	0
	ra?b	0	0
	ra?c	0	1171875
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	0	0
	ra?h	0	0
.PP
.B "RRD50 (read only) partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	33440
	ra?c	0	1171875
	ra?d	131404	122993  
	ra?e	254397	122993
	ra?f	377390	794485
	ra?g	49324	82080
	ra?h	131404	1040471
.PP
.B "RX33 partitions"
	disk	start	length
.sp
	ra?a	0	2400
	ra?b	0	0
	ra?c	0	2400
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	0	0
	ra?h	0	0
.PP
.B "RX50 partitions"
	disk	start	length
.sp
	ra?a	0	800
	ra?b	0	0
	ra?c	0	800
	ra?d	0	0
	ra?e	0	0
	ra?f	0	0
	ra?g	0	0
	ra?h	0	0
.PP
.B "ESE20 partitions"
	disk	start	length
.sp
	ra?a	0	15884
	ra?b	15884	33440
	ra?c	0	245757
	ra?d	49324	130938
	ra?e	180262	65495
	ra?f	0	0
	ra?g	49324	196433
	ra?h	0	0

.DT
.fi
.PP
Usually the ra?a partition is used for the root file system,
the ra?b partition as a paging area.
The ra?c partition for pack to pack copying because 
it maps the entire disk.
.NXE "MSCP disk interface" "partition tables"
.SH Files
.PN /dev/ra???
.br
.PN /dev/rra???
.SH See Also
nbuf(4), dkio(4), chpt(8), MAKEDEV(8), uerf(8)
.NXE "MSCP disk interface"