hhaaii -- Device Driver

Host adapter-independent SCSI driver

The COHERENT driver  hhaaii implements a host adapter-independent SCSI driver.
It  drives  SCSI hard-disk  drives  and SCSI  tape  drives manufactured  by
Adaptec,  Seagate, and  Future Domain.   As  of this  writing, it  is being
extended to  support other SCSI devices,  such as other makes  of SCSI hard
disks and CD ROM.

hhaaii uses  major number  13.  Devices  can be accessed  as either  block- or
character-special  devices.   The minor  number  specifies  the device  and
partition number for disk-type devices; this  allows the use of up to eight
SCSI identifiers  (SCSI-ID's), with up to four  logical unit numbers (LUNs)
per SCSI-ID  and up  to four  partitions per LUN.   Tape and  other special
devices  decode the  minor  number to  perform special  operations such  as
``rewind on close'' or ``no rewind  on close''.  The first ooppeenn() call on a
SCSI disk device allocates memory for the partition table and reads it into
memory.

See  the release  notes for  further  information regarding  supported host
adapters and peripherals.

_F_i_l_e_s
/ddeevv/ssdd* -- block-special devices
/ddeevv/rrssdd* -- character-special devices

_S_e_e _A_l_s_o
ddeevviiccee ddrriivveerrss, hhaarrdd ddiisskk, ttaappee

_N_o_t_e_s
For a list of the block-special  files via which you can access the devices
that hhaaii supports, see the Lexicon entries for hhaarrdd ddiisskk and ttaappee.

If you  are using an  Adaptec AHA-1540, AHA-1542C, or  AHA-1542CF SCSI host
adapter  with a  drive larger  than  1 gigabyte  and Extended  BIOS support
turned on,  then you must override  the default number of  heads to 255 and
the number  of sectors per track  to _6_3. Note that when  you run the script
/eettcc/ccoonnff/hhaaii/mmkkddeevv (or install COHERENT onto your system), ``255'' appears
as the default choice for the  number of heads; however, the default choice
for number  of sectors is 32.  Therefore,  when you run /eettcc/ccoonnff/hhaaii/mmkkddeevv
or  install COHERENT  for a  system that  has one  of the  above-named SCSI
controllers, you  must select the default setting for  the number of heads,
but you must type ``63'' when asked for the number of sectors per track.

Source code  for hhaaii  is included  in version 4.2  of the  COHERENT Device-
Driver Kit.

hhaaii was written by Chris Hilton.
