International Business Machines Corporation

Gregory Francis Paussa

Joseph Franklin Logan

Joseph Gerald McDonald

William Gavin Holland

Warren D Bailey

Anthony D Walker

Henry Michael Garrett

Steven Howard Johnson

Peter D Beal

Peter Anthony LaBerge

Michele M Ferris

Erik L Dixon

James Steele Gaillard

A LAN adapter is implemented in the communication system to selectively exclude four bytes of the CRC value appended to an end of a frame's information field through the use of a configuration bit in a register. By programming this configuration bit to have a specific logic value, the four-bytes of the CRC value may be selectively copied, together with the data in the frame, into a destination computer system's main memory. Additionally, regardless of the setting of this configuration bit, the four-bytes of the CRC value will always be used to check the integrity of the data in the frame. Stated another way, the configuration bit will only affect whether the four-bytes of the CRC value will be transferred as part of the frame after the CRC check operation has been performed.

Communication system having a local area network adapter for selectively deleting information and method therefor

A LAN adapter for transferring data frames from a LAN to memory buffers in a processor in which the LAN driver follows either the ODI or the NDIS specification. The adapter accumulates the frame length and compares this to the storage capacity of the buffer. If the frame length does not exceed the buffer capacity and the LAN driver implements the ODI specification, the adapter will indicate good status to the driver. If the frame length exceeds the buffer capacity the adapter will either send bad status to the ODI driver or reuse the buffer and send no status. If the driver follows NDIS, status is sent at the end of the frame.

Multi-buffer error detection for an open data-link interface LAN adapter

An alterable device driver development system for supporting various operating systems, network protocols, and adapter hardware interfaces. Each device driver comprises a System, Network and Adapter software component, each component providing services to the other through its associated programming interfaces and being alterable or replaceable according to the requirements of an associated adapter hardware product. The System component supports a set of services defined by the device driver and which can be used by the Network and Adapter components. The Network component manages all interactions of the Adapter component with a network operating system or protocol stack and ensures its applicability and correctness in the context of the device driver operation. The Adapter component provides the functions for operating and managing all interactions with the adapter hardware. A Transformation Path in the Adapter component improves device driver performance by mapping network packet descriptors against adapter packet descriptors in data transferring processes.

Design methodology for device drivers supporting various operating

A system (such as a multiprotocol LAN adapter) for use in a workstation or other processing machine automatically determines the type of network to which the workstation is connected and for automatically determines the type of physical medium to which the workstation is attached. The system has a plurality of different physical ports for supporting various available physical media over which network data may be transmitted. For example, the system may have a port for connecting to shielded twisted pair (STP) wiring, a port for connecting to unshielded twisted pair (UTP) wiring, a port for connecting to coaxial cable, and a port for supporting the Attachment Unit Interface (AUI). Connected to each of these physical ports are various network interface devices for supporting the various available networking protocols, e.g., token ring, Ethernet, etc. Logic circuitry and control software are connected to the network interface devices. In order to determine the valid network connections to the individual ports, a short interrogation frame is successively transmitted by each of the network interface devices to each of the ports. Depending upon the status of each transmission, the system determines what type of network (if any) is connected to and by which type of physical medium. Based upon these two determinations, the workstation can be automatically configured without user intervention.

System and method for determining network connectivity

Growing community of inventors

Cary, NC, United States of America

Gregory Francis Paussa