---
name: "cac"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/cac"
---

# cac(4)

Compaq Smart Array 2/3/4 SCSI RAID controller

## NAME

**cac** – Compaq Smart Array 2/3/4 SCSI RAID controller

## SYNOPSIS

**cac\* at pci?** **cac\* at eisa?**

## DESCRIPTION

The **cac** driver provides support for the following RAID controllers:

- Compaq Integrated Array

- Compaq IAES

- Compaq IDA

- Compaq IDA-2

- Compaq RAID LC2

- Compaq Smart Array 221

- Compaq Smart Array 3100ES

- Compaq Smart Array 3200

- Compaq Smart Array 4200

- Compaq Smart Array 4250ES

- Compaq Smart Array 431

- Compaq SMART

- Compaq SMART-2/E

- Compaq SMART-2/P

- Compaq SMART-2DH

- Compaq SMART-2SL

All the RAID set volume management is done via the card BIOS.

Although the controllers are actual RAID controllers, the driver makes them look just like SCSI controllers. All RAID configuration is done through the controllers' BIOSes.

Monitoring status for the volume and drives in it is done through the [bioctl(8)](/bioctl/8.md) utility; the current status is provided by the [sysctl(8)](/sysctl/8.md) variable *hw.sensors*.

## SEE ALSO

[bio(4)](/bio/4.md), [eisa(4)](/eisa/4.md), [intro(4)](/intro/4.md), [pci(4)](/pci/4.md), [scsi(4)](/scsi/4.md), [sd(4)](/sd/4.md), [bioctl(8)](/bioctl/8.md), [sensorsd(8)](/sensorsd/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **cac** driver first appeared in OpenBSD 2.9.

## AUTHORS

The **cac** driver was written by Michael Shalayeff ⟨*mickey@openbsd.org*⟩, inspired by the NetBSD driver by Andrew Doran ⟨*ad@netbsd.org*⟩.