1SI(4)                      Kernel Interfaces Manual                      SI(4)
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NAME

6       si - SI 9500/CDC 9766 moving head disk
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SYNOPSIS

9       /sys/conf/SYSTEM:
10            NSI  si_drives # SI 9500 driver for CDC 9766 disks
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12       /etc/dtab:
13            #Name Unit# Addr   Vector Br Handler(s)      # Comments
14            si    ?     176700 170    5  siintr          # si9500
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16       major device number(s):
17            raw: 18
18            block: 9
19       minor device encoding:
20            bits 0007 specify partition of SI drive
21            bits 0070 specify SI drive
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DESCRIPTION

24       Files  with  minor device numbers 0 through 7 refer to various portions
25       of drive 0; minor devices 8 through 15 refer  to  drive  1,  etc.   The
26       standard  device  names  begin with ``si'' followed by the drive number
27       and then a letter a-h for partitions 0-7 respectively.  The character ?
28       stands here for a drive number in the range 0-7.
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30       The block files access the disk via the system's normal buffering mech‐
31       anism and may be read and  written  without  regard  to  physical  disk
32       records.   There  is  also  a `raw' interface which provides for direct
33       transmission between the disk and the user's read or write  buffer.   A
34       single  read  or  write  call  results in exactly one I/O operation and
35       therefore raw I/O is considerably more efficient when  many  words  are
36       transmitted.   The  names of the raw files conventionally begin with an
37       extra `r.'
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39       In raw I/O the buffer must begin on a word (even) boundary, and  counts
40       should be a multiple of 512 bytes (a disk sector).  Likewise seek calls
41       should specify a multiple of 512 bytes.
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DISK SUPPORT

44       The origin and size (in sectors) of the pseudo-disks on each drive  are
45       as follows:
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47       SI 9500/CDC9766 partitions:
48            disk   start  length       cyls  comments
49            xp?a       0    9120    0 -  14  /
50            xp?b    9120    9120   15 -  29  swap
51            xp?c   18240  234080   30 - 414
52            xp?d  252320  247906  415 - 822*
53            xp?e   18240  164160   30 - 299  /usr
54            xp?f  182400  152000  300 - 549
55            xp?g  334400  165826  550 - 822*
56            xp?h       0  500384    0 - 822  whole pack
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58       Those partitions marked with an asterisk (``*'') actually stop short of
59       the indicated ending cylinder  to  protect  any  bad  block  forwarding
60       information  on  the packs.  The indicated lengths are correct.  Parti‐
61       tion ``h'' must be used to access the bad block forwarding area.  N.B.:
62       the  si  driver  does  not  support  bad block forwarding; the space is
63       reserved in the event bad block forwarding is ever added to the driver.
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FILES

66       /dev/si[0-7][a-h]   block files
67       /dev/rsi[0-7][a-h]  raw files
68       /dev/MAKEDEV        script to create special files
69       /dev/MAKEDEV.local  script to localize special files
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SEE ALSO

72       hk(4), ra(4), ram(4), rk(4), rl(4), rp(4), rx(4), xp(4), dtab(5), auto‐
73       config(8)
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DIAGNOSTICS

76       si%d%c: hard error sn%d cnr=%b err=%b.  An unrecoverable error occurred
77       during transfer of the specified sector of the  specified  disk  parti‐
78       tion.   The  contents  of  the  two error registers are also printed in
79       octal and symbolically with bits decoded.  The error was  either  unre‐
80       coverable,  or a large number of retry attempts (including offset posi‐
81       tioning and drive recalibration) could not recover the error.
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83       si%d%c: hard error sn%d ssr=%b err=%b.  An unrecoverable error occurred
84       during  transfer  of  the specified sector of the specified disk parti‐
85       tion.  The contents of the two error  registers  are  also  printed  in
86       octal  and  symbolically with bits decoded.  The error was either unre‐
87       coverable, or a large number of retry attempts (including offset  posi‐
88       tioning and drive recalibration) could not recover the error.
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BUGS

91       In  raw  I/O  read and write(2) truncate file offsets to 512-byte block
92       boundaries, and write scribbles  on  the  tail  of  incomplete  blocks.
93       Thus,  in  programs  that are likely to access raw devices, read, write
94       and lseek(2) should always deal in 512-byte multiples.
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96       The partition tables for the file systems should be read  off  of  each
97       pack,  as  they are never quite what any single installation would pre‐
98       fer, and this would make packs more portable.
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1023rd Berkeley Distribution       August 20, 1987                          SI(4)
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