Copyright (c) 1995
Justin T. Gibbs. All rights reserved.

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.Dd April 15, 1995 .Dt AHC 4 i386 .Os FreeBSD .Sh NAME .Nm ahc .Nd Adaptec VL/EISA/PCI SCSI host adapter driver .Sh SYNOPSIS For VL/EISA cards: .Cd controller ahc0 at isa? bio irq ? vector ahcintr

p For PCI cards: .Cd controller ahc0

p To enable tagged queueing: .Cd options AHC_TAGENABLE

p For one or more SCSI busses: .Cd controller scbus0 at ahc0 .Sh DESCRIPTION This driver provides access to the .Tn SCSI bus connected to an Adaptec 274x, 284x, 294x, or motherboard-based .Tn AIC7770 or .Tn AIC7870 host adapter. Features include twin and wide bus support, two commands per target in non-tagged-queuing mode, and experimental tagged queuing support enabled with the .Dq Dv AHC_TAGENABLE configuration option.

p Per target configuration performed in the .Tn SCSI-Select menu, accesible at boot in .No non- Ns Tn EISA models or through an .Tn EISA configuration utility for .Tn EISA models, is honored by this driver with the stipulation that the .Tn BIOS must be enabled for .Tn EISA adaptors. This includes synchronous/asynchronous transfers, disconnection, and maximum synchronous negotiation rate settings.

p Note that I/O addresses are determined automatically by the probe routines, but care should be taken when using a 284x

q Tn VESA No local bus controller in an .Tn EISA system. Ensure that the jumpers setting the I/O area for the 284x match the .Tn EISA slot into which the card is inserted to prevent conflicts with other .Tn EISA cards. .Sh BUGS Some Quantum drives (at least the Empire 2100 and 1080s) will not run on an .Tn AIC7870 in synchronous mode at 10MB/s. It is speculated that the Adaptec runs slightly above 10MB/s, causing the drive much confusion. Setting a maximum synchronous negotiation rate of 8MB/s in the .Tn SCSI-Select utility will allow normal function.

p The .Tn SCSI ID of .No Tn AIC7870 Ns -based controllers

q Tn AHA-294x is hard coded to 7 by the driver. The user configured ID can be obtained by querying the adapter, but there is no driver support for this as of yet. .Sh SEE ALSO .Xr aha 4 , .Xr ahb 4 , .Xr cd 4 , .Xr scsi 4 , .Xr sd 4 , .Xr st 4 .Sh AUTHOR The .Nm driver was written by Justin Gibbs. The .Tn AIC7xxx sequencer-code assembler was written by John Aycock. .Sh HISTORY The .Nm driver appeared in .Tn FreeBSD 2.1.