---
name: "gem"
section: "4freebsd"
platform: "linux"
package: "freebsd-manpages"
version: "12.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/gem/4freebsd"
---

# gem(4freebsd)

ERI/GEM/GMAC Ethernet device driver

## NAME

**gem** – ERI/GEM/GMAC Ethernet device driver

## SYNOPSIS

To compile this driver into the kernel, place the following lines in your kernel configuration file:

**device miibus** **device gem**

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
if_gem_load="YES"
```

## DESCRIPTION

The **gem** driver provides support for the GMAC Ethernet hardware found mostly in the last Apple PowerBooks G3s and most G4-based Apple hardware, as well as Sun UltraSPARC machines.

All controllers supported by the **gem** driver have TCP checksum offload capability for both receive and transmit, support for the reception and transmission of extended frames for [vlan(4)](/vlan/4.md) and a 512-bit multicast hash filter.

## HARDWARE

Chips supported by the **gem** driver include:

- Apple GMAC

- Sun ERI 10/100 Mbps Ethernet

- Sun GEM Gigabit Ethernet

The following add-on cards are known to work with the **gem** driver at this time:

- Sun Gigabit Ethernet PCI 2.0/3.0 (GBE/P) (part no. 501-4373)

- Sun Gigabit Ethernet SBus 2.0/3.0 (GBE/S) (part no. 501-4375)

## NOTES

On sparc64 the **gem** driver respects the *local-mac-address?* system configuration variable which can be set in the Open Firmware boot monitor using the **setenv** command or by [eeprom(8)](/eeprom/8.md). If set to “false” (the default), the **gem** driver will use the system's default MAC address for all of its devices. If set to “true”, the unique MAC address of each interface is used if present rather than the system's default MAC address.

Supported interfaces having their own MAC address include the on-board Sun ERI 10/100 Mbps on boards equipped with more than one Ethernet interface and the Sun Gigabit Ethernet 2.0/3.0 GBE add-on cards.

## SEE ALSO

[altq(4)](/altq/4.md), [miibus(4)](/miibus/4.md), [netintro(4)](/netintro/4.md), [vlan(4)](/vlan/4.md), [eeprom(8)](/eeprom/8.md), [ifconfig(8)](/ifconfig/8.md)

## HISTORY

The **gem** device driver appeared in NetBSD 1.6. The first FreeBSD version to include it was FreeBSD 5.0.

## AUTHORS

The **gem** driver was written for NetBSD by Eduardo Horvath ⟨*eeh@NetBSD.org*⟩. It was ported to FreeBSD by Thomas Moestl ⟨*tmm@FreeBSD.org*⟩ and later on improved by Marius Strobl ⟨*marius@FreeBSD.org*⟩. The man page was written by Thomas Klausner ⟨*wiz@NetBSD.org*⟩.