NAME

si − SI 9500/CDC 9766 moving head disk

SYNOPSIS

/sys/conf/SYSTEM:
NSIsi_drives# SI 9500 driver for CDC 9766 disks
 /etc/dtab:
#NameUnit#AddrVectorBrHandler(s) # Comments
si?1767001705siintr # 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 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 therefore 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 sector).  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:

SI 9500/CDC9766 partitions:
disk startlength     cylscomments
xp?a     0  9120  0 -  14/
xp?b  9120  9120 15 -  29swap
xp?c 18240234080 30 - 414
xp?d252320247906415 - 822∗
xp?e 18240164160 30 - 299/usr
xp?f182400152000300 - 549
xp?g334400165826550 - 822∗
xp?h     0500384  0 - 822whole 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 indicated 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/MAKEDEVscript to create special files
/dev/MAKEDEV.localscript 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 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. 

2nd Berkeley Distribution  —  August 20, 1987