NAME

sd − VME SCSI disk adaptor interface

SYNOPSIS

SD0 at address 0x7fffe0/037777740 vector 0x78/0170

DESCRIPTION

sd is the disk interface for Integrated Solution’s SCSI host adaptor for 5 ¼-inch Winchester drives.  The standard (block) device names begin with ‘sd’ followed by the drive number and a letter a-h for partitions 0-7 respectively.  For example, ‘sd0a’ designates the block device for the first partition (a) on the first drive (0). 

Files with minor device numbers 0 through 7 refer to drive 0 partitions; minor devices 8 through 15 refer to drive 1 partitions, etc. 

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; therefore, raw I/O is considerably more efficient when many words are transmitted.  The names of the raw files begin with an extra ‘r.’

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

The sd device supports ST506 drives configured with  the Integrated Solutions SCSI host adaptor and an Adaptec ACB 4000 (MFM encoding) or ACB 4070 (RLL encoded) target disk controller.  The most commonly supported drives are:

CDC 36, 86
Maxtor 1065, 1110, and 1140
Vertex 185

You can obtain drive configuration information in the online file /etc/disktab. Note that /etc/disktab contains two entries for each ST506 drive supported by sd.  Entries with have an "L" appended to them, such as V185L, support drives that have been run length limit (RLL) encoded.  Such drives require the Adaptec ACB 4070 target disk controller. The ST506 entries without the L (e.g V185) support the MFM encoded drives which require the Adaptec ACB 4000 target disk controller.  Each sd drive is divided into disk partitions as follows: where ? stands for the drive number:

sd?aused for the root filesystem
sd?bused as a paging area
sd?cmaps the entire disk

All disk partition tables are calculated using the diskpart(8) program. 

FILES

/dev/sd[0-7][a-h]block files
/dev/rsd[0-7][a-h]raw files

SEE ALSO

rk(4), hp(4)
UNIX 4.3BSD System Administrator Guide (SMM:1)

DIAGNOSTICS

sd%d%c: hard error sn%d cs = %b.  An unrecoverable error occurred during transfer of the specified sector of the specified disk partition.  The contents of the control status register are printed in octal and symbolically with bits decoded.  The error was either unrecoverable, or a large number of retry attempts (including offset positioning and drive recalibration) could not recover the error. 

sd%d: lost interrupt.  As a result of a lost interrupt, sd resets itself and cancels the software state of pending transfers. 

BUGS

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.

A program to analyze the logged error information (even in its present reduced form) is needed. 

The partition tables for the filesystems should be read off of each pack, as they are never quite what any single installation would prefer, and this would make packs more portable. 

4th Berkeley Distribution  —  1 August 1985