GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
Unix |
Unix v6 |
|
 |
hp(4) |
 |
hp RH-11/RP04 moving-head disk The files refer to sections of RP disk drive 0. The files refer to drive 1 etc. This is done since the size of a full RP drive is 170,544 blocks and internally the system is only capable of addressing 65536 blocks. Also since the disk is so large, this allows it to be broken up into more manageable pieces. The origin and size of the pseudo-disks on each drive are as follows:
|
disk |
start |
length |
|||
|
0 |
0 |
9614 |
|||
|
1 |
18392 |
65535 |
|||
|
2 |
48018 |
65535 |
|||
|
3 |
149644 |
20900 |
|||
|
4 |
0 |
40600 |
|||
|
5 |
41800 |
40600 |
|||
|
6 |
83600 |
40600 |
|||
|
7 |
125400 |
40600 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. The 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 and end with a number which selects the same disk section as the corresponding file. 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 calls should specify a multiple of 512 bytes. /dev/hp?, /dev/rhp? |
|
hp(4) | |