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

6       rp - RP-11/RP03 moving-head disk
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DESCRIPTION

9       The  files rp0 ... rp7 refer to sections of RP disk drive 0.  The files
10       rp8 ... rp15 refer to drive 1 etc.  This allows a large disk to be bro‐
11       ken up into more manageable pieces.
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13       The origin and size of the pseudo-disks on each drive are as follows:
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15            disk start     length
16            0    0    81000
17            1    0    5000
18            2    5000 2000
19            3    7000 74000
20            4-7  unassigned
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22       Thus rp0 covers the whole drive, while rp1, rp2, rp3 can serve usefully
23       as a root, swap, and mounted user file system respectively.
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25       The rp files access the disk via the system's normal  buffering  mecha‐
26       nism  and  may  be  read  and  written  without regard to physical disk
27       records.  There is also a `raw' interface  which  provides  for  direct
28       transmission  between  the disk and the user's read or write buffer.  A
29       single read or write call results in  exactly  one  I/O  operation  and
30       therefore  raw  I/O  is considerably more efficient when many words are
31       transmitted.  The names of the raw RP files begin with rrp and end with
32       a  number  which  selects the same disk section as the corresponding rp
33       file.
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35       In raw I/O the buffer must begin on a word boundary.
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FILES

38       /dev/rp?, /dev/rrp?
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SEE ALSO

41       hp(4)
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BUGS

44       In raw I/O read and write(2) truncate file offsets  to  512-byte  block
45       boundaries,  and  write  scribbles  on  the  tail of incomplete blocks.
46       Thus, in programs that are likely to access raw  devices,  read,  write
47       and lseek(2) should always deal in 512-byte multiples.
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