Networking NOMAD

The Nomad is equiped with a RangeLan2 wireless ethernet device.  This enables it to hook into a ethernet LAN when within range of the wireless hub.  There are drivers available for the card under Linux.  They can be compiled as a loadable kernel module.  This allows it to be dynamically loaded and unloaded, assisting debuging as well as reducing the size of the basic kernel.

Figure 6. RangeLan2 Wireless Ethernet Device on Top of NOMAD 200

Getting the card to function correctly, however, was a bit challenging.  The driver module initially would fail at startup with the message "Error reading device ROM"  We feared there was some fault in card itself.  However, we decided to track down possible software/configuration problems first.  We checked to make sure the interrupt and memory mapped io ports were not already occupied, using the proc system.  Then we tried to use "pnpdump" to connect the card.  When this failed, we realised that
the card must be a legacy ISA device and thus might need special configuration in the BIOS.  Entering the BIOS setup, we reserved IRQ 11 (which the card uses) for legacy ISA devices, instead of putting it in the PCI/PnP pool.  After this the driver worked.  We used the "insmod" command to load the module, with the arguments "CardType=0 io=0x270 irq=11"

After this, we configured the ethernet driver in the standard way for a Mandrake system.  Occasionally, the card had trouble establishing connectivity with the hub, but moving the antenna helped this.  Once connectivity was established, packet loss did not seem to be a problem even when the antenna was moved back.  After this, ssh was installed on the machine from precompiled binaries.