1HP(4) Kernel Interfaces Manual HP(4)
2
6 hp - RH-11/RP04, RP05, RP06 moving-head disk
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9 The octal representation of the minor device number is encoded idp,
10 where i is an interleave flag, d is a physical drive number, and p is a
11 pseudodrive (subsection) within a physical unit. If i is 0, the ori‐
12 gins and sizes of the pseudodisks on each drive, counted in cylinders
13 of 418 512-byte blocks, are:
14 disk start length
16 0 0 23
17 1 23 21
18 2 0 0
19 3 0 0
20 4 44 386
21 5 430 385
22 6 44 367
23 7 44 771
24 If i is 1, the minor device consists of the specified pseudodisk on
26 drives numbered 0 through the designated drive number. Successively
27 numbered blocks are distributed across the drives in rotation.
28 Systems distributed for these devices use disk 0 for the root, disk 1
30 for swapping, and disk 4 (RP04/5) or disk 7 (RP06) for a mounted user
31 file system.
32 The block files access the disk via the system's normal buffering mech‐
34 anism and may be read and written without regard to physical disk
35 records.
36 A `raw' interface provides for direct transmission between the disk and
38 the user's read or write buffer. A single read or write call results
39 in exactly one I/O operation and therefore raw I/O is considerably more
40 efficient when many words are transmitted. The names of the raw files
41 conventionally begin with an extra `r.' In raw I/O the buffer must
42 begin on a word boundary, and raw I/O to an interleaved device is
43 likely to have disappointing results.
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46 /dev/rp?, /dev/rrp?
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49 rp(4)
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52 In raw I/O read and write(2) truncate file offsets to 512-byte block
53 boundaries, and write scribbles on the tail of incomplete blocks.
54 Thus, in programs that are likely to access raw devices, read, write
55 and lseek(2) should always deal in 512-byte multiples.
56 Raw device drivers don't work on interleaved devices.
58 HP(4)