BR(4) UNIX Programmer's Manual BR(4) NAME br - EATON BR1537/BR1711 1538[A,B,C,D] moving head disk SYNOPSIS /sys/conf/SYSTEM: NBR _b_r__d_r_i_v_e_s # EATON 1537/1711, EATON 1538A, B, C, D /etc/dtab: #Name Unit# Addr Vector Br Handler(s) # Comments br ? 176710 254 5 brintr # Eaton 1537/8 major device number(s): raw: 20 block: 11 minor device encoding: bits 0007 specify partition of BR drive bits 0070 specify BR drive 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. There are four drive types supported by the Eaton BR1537 and BR1711 controllers, these are the 1538A (50 Mb), 1538B (80 Mb), 1538C (200 Mb) and 1538D (300 Mb). Capacities are unformatted megabytes. The standard device names begin with ``br'' 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. 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 there- fore raw I/O is considerably more efficient when many words are transmitted. The names of the raw files conventionally begin with an extra `r.' In raw I/O the buffer must begin on a word (even) boundary, and counts should be a multiple of 512 bytes (a disk sec- tor). Likewise _s_e_e_k calls should specify a multiple of 512 bytes. DISK SUPPORT The size (in sectors) of the pseudo-disks on each drive are as follows: Printed 11/26/99 August 20, 1988 1 BR(4) UNIX Programmer's Manual BR(4) 1538A partitions: disk length cyls comments br?a 18260 0 - 165 1538A has 22 sec/trk, 5 trk/cyl br?b 12210 166 - 276 br?c 59180 277 - 814 br?d unused br?e unused br?f unused br?g unused br?h 89650 0 - 814 1538B partitions: disk length cyls comments br?a 18400 0 - 114 1538B has 32 sec/trk, 5 trk/cyl br?b 12320 115 - 190 br?c 99840 191 - 814 br?d unused br?e unused br?f unused br?g unused br?h 99840 0 - 814 1538C partitions: disk length cyls comments br?a 18392 0 - 43 1538C has 22 sec/trk, 19 trk/cyl br?b 12122 44 - 72 br?c 231990 73 - 627 br?d 78166 628 - 814 br?e unused br?f unused br?g unused br?h 340670 0 - 814 1538D partitions: disk length cyls comments br?a 18240 0 - 29 1538D has 32 sec/trk, 19 trk/cyl br?b 12160 30 - 49 br?c 232256 50 - 431 br?d 232256 432 - 813 br?e unused br?f unused br?g unused br?h 495520 0 - 814 FILES /dev/br[0-7][a-h] block files /dev/rbr[0-7][a-h] raw files /dev/MAKEDEV script to create special files /dev/MAKEDEV.local script to localize special files SEE ALSO ra(4), ram(4), rk(4), rl(4), rx(4), si(4), xp(4), dtab(5), Printed 11/26/99 August 20, 1988 2 BR(4) UNIX Programmer's Manual BR(4) autoconfig(8) DIAGNOSTICS br%d%c: hard error sn%d cs2=%b ds=%b er=%b. An unrecover- able error occurred during transfer of the specified sector of the specified disk partition. The contents of the cs2, ds and er registers are printed in octal and symbolically with bits decoded. The error was either unrecoverable, or a large number of retry attempts (including offset positioning and drive recalibration) could not recover the error. BUGS In raw I/O _r_e_a_d and _w_r_i_t_e(2) truncate file offsets to 512- byte block boundaries, and _w_r_i_t_e scribbles on the tail of incomplete blocks. Thus, in programs that are likely to access raw devices, _r_e_a_d, _w_r_i_t_e and _l_s_e_e_k(2) should always deal in 512-byte multiples. DEC-standard error logging should be supported. A program to analyze the logged error information (even in its present reduced form) is needed. 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. Only the 1538D (300Mb) disk has been used with this driver, the _d_i_s_k_t_a_b(5) file and _n_e_w_f_s(8) program only know about the 1538D. Printed 11/26/99 August 20, 1988 3