Introduction to Data Communications
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38d. Network Interface Card Drivers

Network Interface Card Drivers are the software interface between the Network Card Hardware/Firmware and the Network Operating System Data Link layer. The Network Card device driver is a device driver loaded in config.sys. The Network Card consists of Firmware and Hardware.

The Firmware is the program stored on the network card's ROM (BIOS) and configuration information stored in E2ROM. The configuration information would be the IRQ, Base Memory Address, Transceiver Type, etc.. for the Network Card. The Hardware would be the physical components: ICs, connectors, etc..

There are basically 3 types of Network Card Drivers:

NDIS stands for Network Driver Interface Specification. NDIS drivers are used by Microsoft based Network Operating Systems such as Microsoft LAN Manager, Windows NT, Windows for WorkGroups and IBM's OS/2.

ODI stands for Open Datalink Interface. ODI drivers are used by Novell's Network Operating System and Apple.

Packet drivers use software interrupts to interface to the network card. Many non-commercial programs (shareware and freeware) use Crnywr packet driver interfaces.

The 3 Network Driver Types are not compatible with each other but most Network Operating Systems (Novell, WFWG, etc..) can use either NDIS or ODI. The NOS (Network Operating System) determines which type of Network Driver can be used. Regardless of the Network Driver type used, all have a network device driver loaded into memory during boot up and a network protocol bound to the network card.

The purpose of the Network Drivers is to decouple the network adapter's device driver from the higher layer protocols. The higher layer protocols can be IPX/SPX for Novell, Netbios for Microsoft, TCP/IP for Unix etc..

Introduction to Data Communications
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