term% cat index.txt HS(4) Kernel Interfaces Manual HS(4)
NAME
hs - RH11/RS03-RS04 fixed-head disk file
DESCRIPTION
The files hs0 ... hs7 refer to RJS03 disk drives 0 through 7. The
files hs8 ... hs15 refer to RJS04 disk drives 0 through 7. The RJS03
drives are each 1024 blocks long and the RJS04 drives are 2048 blocks
long.
The hs files access the disk via the system's normal buffering mecha‐
nism and may be read and written without regard to physical disk
records. There is also a `raw' inteface 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 nor‐
mal interface.
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 lseek calls should
specify a multiple of 512 bytes.
FILES
/dev/hs?, /dev/rhs?
HS(4)