.\" SCCSID: @(#)ra.4	2.1	3/10/87.TH ra 4.SH Namera \- 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 ..PPThis 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)..PPThe following rules are used to determine the major and minor numbers thatare associated with an .PN ratype disk.  There is a range of major numbers used to represent  .PN ra disks.  Each major number represents 32 disks.  For this reason, the firstmajor number associated with .PN radisks represents logical unit number 0 through logical unit number 31.Similarly the second major number represents logical unit number 32 throughlogical unit number 63. The minor number is used to represent both the logical unitnumber and partition.  A disk partition refers to a designated portionof the physical disk.To accomplish this, the 8-bit minor number is broken upinto two parts.  The low three bits of the minor number specify a diskpartition.  These three bits allow for the naming of eight partitions.  Thepartitions are named a,b,c,d,e,f,g and h.  The upper five bits of the minornumber specify the logical unit number within a group of 32 disks..PPThe device special file names associated with .PN ra disks are based on the following conventions, which are closely associated withthe 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 rais the logical unit number and then a letter, a through h, to representthe partition.  Throughout this reference page,the question mark (?) character representsthe logical unit number in the name of the device special file.  For examplera?b could represent ra0b, ra1b, and so on..PPThe following examples illustrate how the logical unit number iscalculated given the major and minor number of an .PN radisk.  For the device special file rra6a, the major number is 60 and theminor 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 thisreason, 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 60/48refers to the ``a'' partition of logical unit 6.  As another example, the following computation determinesthe logical unit number corresponding to the major/minorpair 62,49.  The low 3 bits of the minor number gives the number 1, whichis 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 givesa value of 2.  This means that 2 groups of 32 disks preceed the unit inquestion.  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..PPThe disk can be accessed through either the block special file or the character special file.  The block special file accesses the disk usingthe file system's normal buffering mechanism.  Reads and writes to the blockspecial file can specify any size.  This avoids the need to limit data transfers to the size of physical disk records and to calculate offsetswithin disk records.The file system may break up large read and write requests into smaller fixed size transfers to the disk..PPThe character special file provides a raw interface which allows fordirect 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 interfacemust 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 seekcalls 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 arepossible to any raw MSCP device. (See .MS nbuf 4for more information.).SH Disk Support.NXR "MSCP disk interface" "disk support"This driver handles all disk drives that may be connected to an MSCP-basedcontroller.  Consult the .I "ULTRIX Software Product Description" to determine which controllersare supported for which CPU types and hardware configurations..PPThe starting location and length (in 512-byte sectors) of the disk partitions of eachdrive are shown in the following table.Partition sizes can be changedby .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.PPUsually 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 Alsonbuf(4), dkio(4), chpt(8), MAKEDEV(8), uerf(8).NXE "MSCP disk interface"