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Diffstat (limited to 'static/unix-v10/man4/up.4')
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diff --git a/static/unix-v10/man4/up.4 b/static/unix-v10/man4/up.4 new file mode 100644 index 00000000..3198f630 --- /dev/null +++ b/static/unix-v10/man4/up.4 @@ -0,0 +1,65 @@ +.TH UP 4 +.SH NAME +up \- emulex sc21/ampex 9300 UNIBUS moving head disk +.SH 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. +.PP +The origin and size of the pseudo-disks on each drive are +as follows: +.PP +.ta .5i +\w'000000 'u +\w'000000 'u +.nf +9300 partitions + disk start byte + 0 0 15884 + 1 16416 33440 + 2 0 500992 + 3 341696 15884 + 4 358112 55936 + 5 414048 36944 + 6 341696 159296 + 7 49856 291346 +.DT +.fi +.PP +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.' +.SH FILES +.ta 2i +/dev/up[0-3][a-h] block files +.br +/dev/rup[0-3][a-h] raw files +.SH SEE ALSO +rp(4) +.SH BUGS +In raw I/O +.I read +and +.IR write (2) +truncate file offsets to 512-byte block boundaries, +and +.I write +scribbles on the tail of incomplete blocks. +Thus, +in programs that are likely to access raw devices, +.I read, write +and +.IR lseek (2) +should always deal in 512-byte multiples. |
