Query: ra
OS: ultrix
Section: 4
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
ra(4) Kernel Interfaces Manual ra(4) Name ra - MSCP disk interface Syntax For UNIBUS, Q-bus: controller uda0 at uba? controller uq0 at uda0 csr 0172150 vector uqintr disk ra0 at uq0 drive 0 For VAX BI: controller kdb0 at vaxbi0 node 4 controller uq0 at kdb0 vector uqintr disk ra0 at uq0 drive 0 controller bvpssp0 at aio1 vector bvpsspintr disk ra0 at bvpssp0 drive 0 For MSI Bus: adapter msi0 at nexus? controller dssc0 at msi0 msinode 0 disk ra0 at dssc0 drive 3 For VAX CI/HSC: adapter ci0 at nexus? adapter ci0 at vaxbi? node? controller hsc0 at ci0 cinode 6 disk ra0 at hsc0 drive 3 Description Prior to Version 2.0, this device was referenced by 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). The following rules are used to determine the major and minor numbers that are associated with an type disk. There is a range of major numbers used to represent disks. Each major number represents 32 disks. For this reason, the first major number associated with 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. The device special file names associated with 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 for the block special file and for the raw (character) special file. Following the 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. The following examples illustrate how the logical unit number is calculated given the major and minor number of an 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 num- ber 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. 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. The character special file provides a raw interface which allows for direct transmission between the disk and the user's read or write buf- fer. 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, 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 for more information.) Disk Support This driver handles all disk drives that may be connected to an MSCP-based controller. Consult the ULTRIX Software Product Description to determine which controllers are supported for which CPU types and hardware configurations. 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 For further information, see RA60 partitions disk start length 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 RA70 partitions disk start length 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 RA71 partitions disk start length 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 RA72 partitions disk start length 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 RA80 partitions disk start length 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 RA81 partitions disk start length 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 RA82 partitions disk start length 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 RA90 partitions disk start length 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 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 RD31 partitions disk start length 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 RD32 partitions disk start length 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 RD51 partitions disk start length 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 RD52 partitions disk start length 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 RD53 partitions disk start length 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 RD54 partitions disk start length 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 RF30 partitions disk start length 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 RF31 partitions disk start length 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 RF71 partitions disk start length 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 RRD40 (read only) partitions disk start length 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 RRD50 (read only) partitions disk start length 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 RX33 partitions disk start length 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 RX50 partitions disk start length 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 ESE20 partitions disk start length 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 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. Files See Also nbuf(4), dkio(4), chpt(8), MAKEDEV(8), uerf(8) ra(4)