The Iomega NAS 100d is a small ARM based gadget which has one
Ethernet, two USB ports, an internal IDE hard drive and an internal
Atheros WiFi card.  It is much like the Linksys NSLU2, except that it
has the internal hard drive, the wireless interface, and also has
twice the FLASH and twice the RAM compared to the NSLU2.  It shares
the NSLU2 user community at http://www.nslu2-linux.org/

The firmware is based on RedBoot but unlike the NSLU2 there is no
bootloader upgrade mode, so for the initial flash of Debian firmware
you need to either use the stock firmware web upgrade facility
(preferred, and requires no hardware modifications), or you need to
have a serial port (soldering holes for a normal RS232 interface are
on the board) and transfer the firmware via the bootloader serial
download functionality.  The RedBoot on the NAS100d has full FIS table
functionality, allowing you to create and delete FIS partitions via
the bootloader serial console.  There is 2 MB of space in the 'kernel'
partition, 6MB of space in the 'filesystem' partition, and 6MB of
space in the 'usr' partition.

However, the stock RedBoot does not pass the machine ID for the
NAS100d kernel. Since we want to use a generic ixp4xx kernel, we've
worked around this limitation by using a 2nd boot loader, APEX.  We
put APEX in an unused part of the flash and tell RedBoot to boot from
APEX instead of booting the kernel directly.  Effectively, this means
that there is:
 - A partition for APEX
 - A partition for the kernel
 - A partition for the initrd

A description of the NAS100d's flash layout can be found at
http://www.nslu2-linux.org/wiki/NAS100d/FisList

There is also a problem with Ethernet: the ixp4xx chip has built-in
Ethernet but requires a microcode.  Up until recently, there was only a
driver from Intel, but now a GPLed driver that is aiming for mainline
inclusion is available.  It's still not clear how to handle the microcode
but at the moment unofficial images with it are distribution from
nslu2-firmware.net

Apart from this, the NAS100d is pretty easy to support.