controller xyc0 at vme16d16 ? csr 0xee40 priority 2 vector xyintr 0x48 controller xyc1 at vme16d16 ? csr 0xee48 priority 2 vector xyintr 0x49 disk xy0 at xyc0 drive 0 disk xy1 at xyc0 drive 1 disk xy2 at xyc1 drive 0 disk xy3 at xyc1 drive 1
The two controller lines given in the synopsis sections above specify the first and second Xylogics 450 or 451 SMD disk controller in a Sun system.
Files with minor device numbers 0 through 7 refer to various portions of drive 0; minor devices 8 through 15 refer to drive 1, and so on. The standard device names begin with xy followed by the drive number and then a letter a-h for partitions 0-7 respectively. The character `?' stands here for a drive number in the range 0-7.
The block files access the disk using 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 usually results in only one I/O operation; 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.
When using raw I/O, transfer counts should be multiples of 512 bytes (the size of a disk sector). Likewise, when using lseek.2v to specify block offsets from which to perform raw I/O, the logical offset should also be a multiple of 512 bytes.
Due to word ordering differences between the disk controller and Sun computers, user buffers that are used for raw I/O must not begin on odd byte boundaries.
If flags 0x1 is specified, the overlapped seeks feature for that drive is turned off. Note: to be effective, the flag must be set on all drives for a specific controller. This action is necessary for controllers with older firmware, which have bugs preventing overlapped seeks from working properly.
The xy?a partition is normally used for the root file system on a disk, the xy?b partition as a paging area, and the xy?c partition for pack-pack copying (it normally maps the entire disk). The rest of the disk is normally the xy?g partition.
Older revisions of the firmware do not properly support overlapped seeks. This will only affect systems with multiple disks on a single controller. If a large number of ``zero sector count'' errors appear, you should use the flags field to disable overlapped seeks.
Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97