Abstract: 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.

Abstract: A method for transferring data between non-contiguous buffers in a memory and an I/O device via a system I/O bus uses a descriptor queue stored in memory. Each descriptor points to a buffer and includes the length of the buffer. The I/O device is provided with the base address of the queue, the length of the queue and a current address which at initialization is the same as the base address. When data is to be transferred a device driver located in the processor sends the number of available descriptors (DescrEnq) to the I/O device which accesses the descriptors individually or in burst mode to gain access to the data buffers identified by the descriptors.

Abstract: 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.

Abstract: A method for transferring data between non-contiguous buffers in a memory and an I/O device via a system I/O bus uses a descriptor queue stored in memory. Each descriptor points to a buffer and includes the length of the buffer. The I/O device is provided with the base address of the queue, the length of the queue and a current address which at initialization is the same as the base address. When data is to be transferred a device driver located in the processor sends the number of available descriptors (DescrEnq) to the I/O device which accesses the descriptors individually or in burst mode to gain access to the data buffers identified by the descriptors.

Abstract: An interrupt mechanism associated with a peripheral devise is connected to a processor by an interrupt driven I/O bus. The mechanism includes an n input System Interrupt Status Register (SISR) which collects up to n different interrupts from the device during a predetermined time period. Gate and timing circuits under control of signals provided by the processor regulate the frequency of the interrupts thus reducing the number of interrupt operations required to service the device.

Abstract: An adapter or add-in card for using in a peripheral component interconnect (PCI) computer includes a universal module which couples the card to the PCI bus. The module includes a set of selectively programmable configuration registers which are loaded by a microprocessor on the adapter. A circuit arrangement on the module issues a command which inhibits the PCI processor from accessing the configuration registers until fully loaded.