NAME

rp − RP11/RP02 or RP03 moving-head disk

DESCRIPTION

The RP11 controller supports a mix of up to eight RP02/RP03 disk drives. 

The files rp0 through rp7 refer to sections of RP disk drive 0.  The files rp8 through rp15 refer to drive 1 etc.  This allows a large disk to be broken up into more manageable pieces. 

Refer to the ULTRIX-11 System Management Guide for more information about logical disk names and for disk partition sizes. 

The rp 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 RP files begin with rrp and end with a number which selects the same disk section as the corresponding rp file. 

In raw I/O the buffer must begin on a word boundary. 

FILES

/dev/rp##, /dev/rrp##

RESTRICTIONS

In raw I/O read and write truncate file offsets to 512-byte block boundaries, and write writes data on the tail of incomplete blocks.  Thus, in programs that are likely to access raw devices, read, write, and lseek should always deal in 512-byte multiples. 

SEE ALSO

ULTRIX-11 System Management Guide
ULTRIX-11 Software Technical Description