1RP(4) Kernel Interfaces Manual RP(4)
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6 rp - RP-11/RP03 moving-head disk
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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.
12 The origin and size of the pseudo-disks on each drive are as follows:
14 disk start length
16 0 0 81000
17 1 0 5000
18 2 5000 2000
19 3 7000 74000
20 4-7 unassigned
21 Thus rp0 covers the whole drive, while rp1, rp2, rp3 can serve usefully
23 as a root, swap, and mounted user file system respectively.
24 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.
34 In raw I/O the buffer must begin on a word boundary.
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38 /dev/rp?, /dev/rrp?
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41 hp(4)
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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.
48 RP(4)