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GEM(4)			     Kernel Interfaces Manual			  GEM(4)

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):

	   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 capa-
     bility for both receive and transmit, support for the reception and  trans-
     mission of extended frames for vlan(4) 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 configura-
     tion variable which can be set in the Open Firmware boot monitor using  the
     setenv  command  or by eeprom(8).	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), miibus(4), netintro(4), vlan(4), eeprom(8), ifconfig(8)

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>.

FreeBSD 8.2			December 25, 2009			  GEM(4)
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