---
name: "prtc"
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/prtc"
---

# prtc(4)

PROM real-time clock

## NAME

**prtc** – PROM real-time clock

## SYNOPSIS

**prtc0 at mainbus0**

## DESCRIPTION

The **prtc** driver provides support for the time of day service provided by the PROM on systems that do not have a hardware real-time clock like the Sun Enterprise 10000, Sun Fire 12K and Sun Fire 15K.

## SEE ALSO

[intro(4)](/intro/4.md)

## HISTORY

The **prtc** driver first appeared in OpenBSD 4.4.

## AUTHORS

The **prtc** driver was written by Mark Kettenis ⟨*kettenis@openbsd.org*⟩.