.TH RP 4 .SH NAMErp \- RP-11/RP03 moving-head disk.SH DESCRIPTIONThe files.I "rp0 ... rp7"refer to sections of RP disk drive 0.The files.I "rp8 ... rp15"refer to drive 1 etc.This allows a large disk to be broken upinto more manageable pieces..PPThe origin and size of the pseudo-disks on each drive areas follows:.PP.br	disk	start	length.br	0	0	81000.br	1	0	5000.br	2	5000	2000.br	3	7000	74000.br	4-7	unassigned.PPThus rp0 covers the whole drive,while rp1, rp2, rp3 can serve usefully as a root, swap, andmounted user file system respectively..PPThe.I rpfilesaccess the disk via the system's normalbuffering mechanismand may be read and written without regard tophysical disk records.There is also a `raw' interfacewhich provides for direct transmission between the diskand the user's read or write buffer.A single read or write call results in exactly one I/O operationand therefore raw I/O is considerably more efficient whenmany words are transmitted.The names of the raw RP filesbegin with.I rrpand end with a number which selects the same disksection as the corresponding.I rpfile..PPIn raw I/O the buffer must begin on a word boundary..SH FILES/dev/rp?, /dev/rrp?.SH SEE ALSOhp(4).SH BUGSIn raw I/O.I readand.IR write (2)truncate file offsets to 512-byte block boundaries,and.I writescribbles on the tail of incomplete blocks.Thus,in programs that are likely to access raw devices,.I read, writeand.IR lseek (2)should always deal in 512-byte multiples.