---
name: "ahb"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/ahb"
---

# ahb(4)

Adaptec EISA SCSI host adapter driver

## NAME

**ahb** – Adaptec EISA SCSI host adapter driver

## SYNOPSIS

**device** **ahb** **device** **scbus**

## DESCRIPTION

This driver provides access to the SCSI bus connected to an Adaptec AHA-174X host adapters in “*enhanced*” mode. Tagged queueing and synchronous SCSI transfers are supported.

## HARDWARE

The **ahb** driver supports the following SCSI host adapters:

- Adaptec AHA-1740

- Adaptec AHA-1742

- Adaptec AHA-1740A

- Adaptec AHA-1742A

## CAVEATS

The Adaptec 174X is very sensitive to SCSI bus termination and cable length. It may also have difficulties operating with some modern devices that, due to their speed, expose timing problems in the controller. There are no known mechanisms for working around device incompatibilities of this nature.

## SEE ALSO

[aha(4)](/aha/4.md), [ahc(4)](/ahc/4.md), [aic(4)](/aic/4.md), [cd(4)](/cd/4.md), [da(4)](/da/4.md), [sa(4)](/sa/4.md), [scsi(4)](/scsi/4.md)

## AUTHORS

The **ahb** driver was written by Justin T. Gibbs.