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SI(4) UNIX Programmer's Manual SI(4) NAME si - SI 9500/CDC 9766 moving head disk SYNOPSIS /sys/conf/SYSTEM: NSI si_drives # SI 9500 driver for CDC 9766 disks /etc/dtab: #Name Unit# Addr Vector Br Handler(s) # Comments si ? 176700 170 5 siintr # si9500 major device number(s): raw: 18 block: 9 minor device encoding: bits 0007 specify partition of SI drive bits 0070 specify SI 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. The standard device names begin with ``si'' followed by the drive number and then a letter a-h for par- titions 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 seek calls should specify a multiple of 512 bytes. DISK SUPPORT The origin and size (in sectors) of the pseudo-disks on each drive are as follows: Printed 11/26/99 August 20, 1987 1 SI(4) UNIX Programmer's Manual SI(4) SI 9500/CDC9766 partitions: disk start length cyls comments xp?a 0 9120 0 - 14 / xp?b 9120 9120 15 - 29 swap xp?c 18240 234080 30 - 414 xp?d 252320 247906 415 - 822* xp?e 18240 164160 30 - 299 /usr xp?f 182400 152000 300 - 549 xp?g 334400 165826 550 - 822* xp?h 0 500384 0 - 822 whole pack Those partitions marked with an asterisk (``*'') actually stop short of the indicated ending cylinder to protect any bad block forwarding information on the packs. The indi- cated lengths are correct. Partition ``h'' must be used to access the bad block forwarding area. N.B.: the si driver does not support bad block forwarding; the space is reserved in the event bad block forwarding is ever added to the driver. FILES /dev/si[0-7][a-h] block files /dev/rsi[0-7][a-h] raw files /dev/MAKEDEV script to create special files /dev/MAKEDEV.local script to localize special files SEE ALSO hk(4), ra(4), ram(4), rk(4), rl(4), rp(4), rx(4), xp(4), dtab(5), autoconfig(8) DIAGNOSTICS si%d%c: hard error sn%d cnr=%b err=%b. An unrecoverable error occurred during transfer of the specified sector of the specified disk partition. The contents of the two error registers are also 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. si%d%c: hard error sn%d ssr=%b err=%b. An unrecoverable error occurred during transfer of the specified sector of the specified disk partition. The contents of the two error registers are also 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 read and write(2) truncate file offsets to 512- byte block boundaries, and write scribbles on the tail of incomplete blocks. Thus, in programs that are likely to access raw devices, read, write and lseek(2) should always Printed 11/26/99 August 20, 1987 2 SI(4) UNIX Programmer's Manual SI(4) deal in 512-byte multiples. 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. Printed 11/26/99 August 20, 1987 3
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