SEA(4)

NAME
sea - Seagate ST01/ST02, Future Domain TMC-885, TMC-950 SCSI adapter driver

SYNOPSIS
With explicit memory and IRQ parameters:
controller sea0 at isa? bio irq 5 iomem 0xc8000 vector seaintr

With automatic memory address detection and no IRQ:
controller sea0 at isa?

controller scbus0

For each connected disk:
device sd0

For each connected tape device:
device st0

For one or more cdroms:
device cd0

DESCRIPTION
This driver provides access to SCSI devices connected to Seagate ST01/ST02 or Future Domain TMC-885, TMC-950 SCSI adapter.

It's possible to use the Seagate ST01/ST02 adapter without IRQ line. The data rate then slightly decreases (by 20-30%).

The flags keyword in the configuration file can be used to set some adapter driver parameters:

Bits Description
------------------------------------------
0x01 Disable SCSI bus parity check.

The original Seagate ST02 BIOS cannot coexist with IDE or any other disk controller because it does not share BIOS disk drive numbers (80h, 81h) with others. The probing code of the driver allows using ST02 controller without BIOS: just unplug the ST02 BIOS chip from the board.

Another problem is the floppy adapter on ST02 which could not be disabled by jumpers. The ST02 adapter it the best as a cheap solution for atttaching the tape and CD-ROM drives, and an extra floppy controller is just a headache. There exist a simple workaround: cutting off the AEN signal (A11 contact on ISA connector). AEN then goes high and disables the floppy adapter port address decoder.

Some motherboards also have a problem with ST02 conflicting with IDE during IDE data write phase. It seems than ST02 makes some noise on /IOW line. The /IOW line is used only for floppy controller part of ST02, and because it's rarely needed, cutting off the /IOW (contact B13) will help.

Tested on the following hardware:
Adapter: Seagate ST02
Disk: HP D1686
Streamers: Archive Viper 150, Wangtek 5525
CD-ROMs: Toshiba XM-3401, NEC CDR-25

Maximum data rate is about 270-280 kbytes/sec (on 386DX/40).

FILES
/sys/i386/isa/seagate.c
    driver source

SEE ALSO
cd(4), scsi(4), sd(4), st(4)