NAME

hp − RH-11/RP04, RP05, RP06, RM03 moving-head disk

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. 

The origin and size of the pseudo-disks on each drive are as follows:

RP partitions
diskstartlength
009614
196148778
200
300
400
500
610450330220
718392322278

RM partitions
diskstartlength
009600
196008800
200
300
400
500
69600122080
718400113280

It is unwise for all of these files to be present in one installation, since there is overlap in addresses and protection becomes a sticky matter.  Ordinarily devices 0 and 6 (or 0 and 7) will be used. 

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.’

In raw I/O the buffer must begin on a word boundary, and counts should be a multiple of 512 bytes (a disk block).  Likewise seek calls should specify a multiple of 512 bytes. 

FILES

/dev/rp?, /dev/rrp? 

SEE ALSO

rp(4)

7th Edition