IP(4S)

NAME
ip - Disk driver for Interphase 2180 SMD Disk Controller

SYNOPSIS — SUN-2
controller ipc0 at mbio ? csr 0x040 priority 2
controller ipc1 at mbio ? csr 0x044 priority 2
disk ip0 at ipc0 drive0
disk ip1 at ipc0 drive1
disk ip2 at ipc1 drive0
disk ip3 at ipc1 drive1

DESCRIPTION
Special files ip* refer to disk devices controlled by an Interphase SMD 2180 disk controller.

The standard ip device names begin with the letters ``ip'', followed by the drive unit number, followed by a letter from the series a - h to name one of the eight partitions on the drive. For example, /dev/ip1c refers to partition c on the second drive controlled by the Interphase controller.

The device names provide the binding into the minor device numbers for the driver software. Files with minor device numbers 0 through 7 refer to the eight partitions (a - h) of unit 0; files with device numbers 8 through 15 refer to the eight partitions of drive 1, and so on.

The block 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 effficient when many words are transmitted. Raw files conventionally have a leading ``r'' — /dev/rip0c, for instance.

In raw I/O, counts should be a multiple of 512 bytes (a disk sector). Likewise seek calls should specify a multiple of 512 bytes.

DISK SUPPORT

This driver handles all SMD drives by reading a label from sector 0 of the drive which describes the disk geometry and partitioning.

The ip?a partition is normally used for the root file system on a disk, the ip?b partition as a paging area, and the ip?c partition for pack-pack copying (it normally maps the entire disk). The rest of the disk is normally the ip?g partition.

FILES
/dev/ip[0-7][a-h]    block files
/dev/rip[0-7][a-h]    raw files

SEE ALSO
dkio(4S), xy(4S)

DIAGNOSTICS

ipn: SMD-2180
    When booting tells the controller type.

ipn: initialization failed
    Because the controller didn't respond; perhaps another device is at the address the system expected an Interphase controller at.

ipn: error n reading label on head n
    Error reading drive geometry/partition table information.

ipn: Corrupt label on head n
    The geometry/partition label checksum was incorrect.

ipn: Misplaced label on head n
    A disk label was copied to the wrong head on the disk; shoudn't happen.

ipn: Unsupported phys partition # n
    This indicates a bad label.

ipn: unit not online

ipnc: cmd how (msg) blk n
    A command such as read, write, or format encountered a error condition (how): either it failed, the unit was restored, or an operation was retry'ed. The msg is derived from the error number given by the controller, indicating a condition such as "drive not ready", "sector not found" or "disk write protected".

BUGS
In raw I/O read and write(2V) 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.