NAME

hs − RH11/RH70 - RS03, RS04 fixed-head disk

DESCRIPTION

The files rs0 ... rs7 refer to RS03 disk drives 0 through 7.  The files hs0 ... hs7 refer to RS04 disk drives 0 through 7.  The RS03 drives are each 1024 blocks long and the RS04 drives are 2048 blocks long. 

The hs and rs 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 HS files begin with rhs.  The same minor device considerations hold for the raw interface as for the normal interface.  In raw I/O the buffer must begin on a word boundary. 

FILES

/dev/rx#, /dev/rrs#
/dev/hs#, /dev/rhs#

SEE ALSO

ULTRIX-11 Software Technical Description

RESTRICTIONS

This device is obsolete and, although a driver is provided, is not supported by ULTRIX-11. 

In raw I/O read and write(2) truncate file offsets to 512-byte block boundaries, and write scribbles on the tail of incomplete blocks.  Thus, in programs that are likely to access raw devices, read, write and lseek(2) should always deal in 512-byte multiples.