Method and apparatus for transmitting a message from a computer system over a network adapter to the network by performing format conversion and memory verification

摘要

In a computer network having a plurality of nodes with one or more computer systems associated with a node a method for transmitting messages to and from a DOS application resident in a memory to and from the network. The messages to and from the DOS application are handled a virtual device driver resident in the memory which is monitoring the 5C interrupt. The virtual device driver converts an outgoing CCB1 message from the DOS application to a message in a CCB3 32-bit format and an incoming 32-bit CCB3 message to a CCB1 format. The virtual device driver transmits the CCB3 message to a physical device driver resident in system memory. The physical device converts messages between the CCB3 32-bit format and a CCB3 16-bit format. The physical device driver transmits and receives 16-bit CCB3 messages to and from a logical link control protocol driver resident in the memory. The logical link control protocol driver is preferably written to the ISO 8802-2 standards and passes and receives messages to and from the MAC layer and the LAN adapter. With an incoming message the virtual device driver arms a context hook which fires when the operating system has allocated sufficient memory to the DOS application resident Virtual 86 mode before transmitting the CCB1 message to the DOS application.