---
name: "siop"
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/siop"
---

# siop(4)

LSI/Symbios Logic/NCR 53c8xx SCSI interface

## NAME

**siop** – LSI/Symbios Logic/NCR 53c8xx SCSI interface

## SYNOPSIS

**siop\* at pci?**

**# hppa** **siop\* at mainbus? irq 3** **siop\* at phantomas? irq 3** **siop\* at uturn? irq 3**

## DESCRIPTION

The **siop** driver provides support for following LSI/Symbios Logic/NCR 53c8xx and related SCSI controller chips:

- 53c720 and 53c770 (Fast-Wide SCSI)

- 53c810, 53c810a and 53c815 (Fast SCSI)

- 53c820, 53c825 and 53c825a (Fast-Wide SCSI)

- 53c860 (Ultra SCSI)

- 53c875 and 53c875j (Ultra-Wide SCSI)

- 53c876 (Dual Ultra-Wide SCSI)

- 53c885 (Ultra-Wide SCSI and Ethernet)

- 53c895 and 53c895a (Ultra2-Wide SCSI)

- 53c896 (PCI 64bit, dual Ultra2-Wide SCSI)

- 53c1010 (PCI 64bit, dual Ultra3-Wide SCSI. *NOTE*: at this time **siop** supports at most Ultra2-Wide with this chip)

- 53c1510D (dual Ultra2-Wide SCSI)

**siop** replaces the older **ncr** driver which supported most of these devices.

Older 53C700 and 53C710 controllers are supported by the [oosiop(4)](/oosiop/4.md) and [osiop(4)](/osiop/4.md) drivers, respectively.

## SEE ALSO

[cd(4)](/cd/4.md), [ch(4)](/ch/4.md), [intro(4)](/intro/4.md), [oosiop(4)](/oosiop/4.md), [osiop(4)](/osiop/4.md), [pci(4)](/pci/4.md), [scsi(4)](/scsi/4.md), [sd(4)](/sd/4.md), [st(4)](/st/4.md), [uk(4)](/uk/4.md)

## HISTORY

The **siop** driver first appeared in NetBSD 1.5, OpenBSD support was added in OpenBSD 2.9.

## AUTHORS

The **siop** driver was written by Manuel Bouyer ⟨*Manuel.Bouyer@lip6.fr*⟩ for NetBSD. It was ported to OpenBSD with 53c1010 support added by Ken Westerback ⟨*krw@openbsd.org*⟩ using code from the FreeBSD sym-2 driver written by Gerard Roudier ⟨*groudier@FreeBSD.org*⟩.