The IBM 8227 Demystified

I should first start out by explaining what an 8227 is (picture at top). IBM's marketing name for it is "Wireless LAN Entry Access Point". The idea is to bridge the traffic from the wireless LAN cards (at lower right of picture) onto standard Ethernet. So the 8227 has a PCMCIA slot in it to plug in one of the wireless cards and a built-in ethernet controller to connect to the wired LAN.

The 8227 has two basic modes of bootup: LPL and RPL. In LPL mode, you use a special version of the wireless LAN Entry card that contains 512kb of Flash EEPROM. You plug that card into any PC that has a PCMCIA socket on it, program the EEPROM, move the card to the 8227, and turn it on. It boots up and starts bridging. This is obviously the easiest way.

However, that mode does require that special card. The most common reason for using the alternate mode (RPL) is that the special card is not available (the other reason being centralized management). RPL boot requires a server on the ethernet to be available for loading up a boot image. This should be explained elsewhere, and aparently it does work for most people. I was not one of those people, however.

[Here's where this stops being an introduction to the 8227...]

No matter what I tried, it would not boot (and in fact still does not boot). But my quest to get it working has led me to much more interesting things.

The boot image that it suppose to load off the network is an imagge of DOS-bootable 360kb floppy. Contains enough IBM PC DOS 5.0 to boot, basic MS Lan Manager client, three NDIS network drivers (the wireless driver, the wired driver, and a special driver to do the bridging), and a two little .COM's that I have yet to determine the function of (FREF.COM and D2EQ13.COM).

Further inquisitiveness led to me taking the lid off. Half of the case is filled with a standard AT-style PC power supply. The other half is filled with a custom PC motherboard that measures about 6in x 7in, with ethernet (TP and AUI) connectors out the back and a panel of 8 LEDs out the front. The motherboard lacks any standard I/O (including video, keyboard, and serial). However, it does contain a NatSemi 82905 ethernet controller and a Cirrus Logic PCMCIA host controller. The chipset is a Taiwanese-standard UMC 82c491. CPU is an intel-branded 486SX-33 in a flat-pack. There's a curious Phoenix, Ltd, sticker on the motherboard, next to a socketted 64kb EPROM. More complete parts list here.

My current quest is to figure out how the boot process works, and hopefully cram a more decent boot protocol into the BIOS (factory protocol is the ancient IBM FIND/FOUND RPL mess). All the boot and BIOS code is in that single 64kb EPROM. What is not in there is the boot-up configuration for the 83905 (it is contained in a seperate EEPROM as per the 83905 databook -- MAC address, etc).

To do that, I'm mapping out all the ROM space. Current happenings can be found here.

Eventually, I hope to run Linux on this thing and do all sorts of neat stuff with it (it will be the smallest general-purpose PC I have). Further progress notes to come.