NAME

el − disk interface

SYNOPSIS

EL0 at address 0x3ff900/17774400 vector 0x70/0160

DESCRIPTION

el is the disk interface for Integrated Solution’s extended RL101 disk controller for 5 ¼-inch Winchester drives. 

The standard (block) device names begin with ‘el’ followed by the drive number and a letter a-h for partitions 0-7 respectively.  For example, ‘el0a’ designates the block device for the first partition (a) on the first drive (0).  The character ? stands here for a drive number in the range 0-7.) 

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 el device supports ST506 drives attached to the Integrated Solutions extended RL101 controller.  The most common of the supported drives are: CDC Wren 36, Maxtor 1065, 1110, 1140, 2085, 2140 and 2190. Their characteristics and the number of sectors allotted to the default partitions on each drive are contained in the /etc/disktab file. 

The disk partitions are normally used as follows:

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

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

FILES

/dev/el[0-7][a-h]block files
/dev/rel[0-7][a-h]raw files

SEE ALSO

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

DIAGNOSTICS

el%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. 

el%d: lost interrupt.  As a result of a lost interrupt, el 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. 

4I BSD  —  1 August 1985