---
name: "wdc"
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/wdc"
---

# wdc(4)

WD100x compatible hard disk controller driver

## NAME

**wdc** – WD100x compatible hard disk controller driver

## SYNOPSIS

**# alpha/i386** **wdc0 at isa? port 0x1f0 irq 14 flags 0x00** **wdc1 at isa? port 0x170 irq 15 flags 0x00** **wdc\* at isapnp?**

**# macppc** **wdc\* at macobio?** **wdc\* at kauaiata?**

**# landisk** **wdc0** **at** **obio?** **port** **0x14000000** **irq** **10**

**# all architectures** **wdc\* at pcmcia?**

**atapiscsi\* at wdc?\* flags 0x0000** **wd\* at wdc? flags 0x0000**

## DESCRIPTION

The **wdc** driver provides the basic functions for the [wd(4)](/wd/4.md) and [atapiscsi(4)](/atapiscsi/4.md) drivers. It supports IDE and EIDE controllers, as well as MFM, RLL, and ESDI on the ISA bus. PCI IDE controllers in legacy mode are also supported, but the [pciide(4)](/pciide/4.md) driver may provide more functionality.

For the [isa(4)](/isa/4.md) front-end, setting **flags** to 0x01 enables 32-bit I/O negotiation. This is known to cause problems with some motherboards.

## SEE ALSO

[atapiscsi(4)](/atapiscsi/4.md), [intro(4)](/intro/4.md), [isa(4)](/isa/4.md), [isapnp(4)](/isapnp/4.md), [macobio(4)](/macobio/4.md), [obio(4)](/obio/4.md), [pciide(4)](/pciide/4.md), [pcmcia(4)](/pcmcia/4.md), [scsi(4)](/scsi/4.md), [wd(4)](/wd/4.md)