Hack 17 Configure Network Cards

Give your network card the resources it needs to get and keep your LAN and Internet traffic flowing smoothly.

Network cards are another enhancement to PCs that had to be squeezed in to the limits of old legacy I/O systems. Because networking usually requires a fast, steady stream of data, it is important that network interface cards have unique and exclusive use of address and IRQ resources. Symptoms of conflicts include the inability to obtain a network address or log on to a server, or poor data transfer performance.

The most successful implementations of early 8- and 16-bit network cards in practice used addresses 280 or 340 and IRQ5 (8-bit systems) or IRQ10 (16-bit systems), depending on the presence or absence of a sound card using IRQ5.

Determining the presence, type, and configuration of older network cards is not well supported in most diagnostic and system information programs. Instead you may have to rely on reading the jumper settings or using a configuration program meant specifically for your network adapter.

If you need Gigabit Ethernet (1000BaseT), you should use a motherboard that has it built in. If you install a 1000BaseT PCI card, it will likely saturate the PCI bus, leaving no bandwidth for other PCI cards. Onboard 1000BaseT uses a separate bus to talk to the CPU and memory.

Today, with PCI and Plug and Play, you seldom have to concern yourself with these issues. Nevertheless, knowing the commonly available configurations is useful should you ever have to configure the drivers and software for a LAN card to work in DOS, which often cannot use PCI net cards because the vendors may not provide DOS drivers for them.

Although well published in IBM specifications, address 300 was "reserved" for use by IBM and prototype devices and recognized as such in many versions of BIOS. IBM even offered a plug-in card that used address 300 for others to develop new products around. Older ISA network cards may be set for address 300, which can cause problems for some older applications. Avoid using address 300 for anything.