---
name: "rd"
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/rd"
---

# rd(4)

ramdisk driver

## NAME

**rd** – ramdisk driver

## SYNOPSIS

**pseudo-device rd** \[*count*\]

## DESCRIPTION

The **rd** driver enables use of system or user memory as a disk. Memory for the disk must be allocated and initialized inside the kernel image at build-time using the **rdsetroot** tool.

## FILES

- */dev/rd??*

  Block mode ramdisk devices.

- */dev/rrd??*

  Raw mode ramdisk devices.

## SEE ALSO

[elf(5)](/elf/5.md), [rdsetroot(8)](/rdsetroot/8.md)