摘要:
A controller and a properly equipped peripheral device of a computer system easily exchange messages having a compressed data format. Both the controller and the peripheral device are configured to communicate using a predefined basic command set employing a predefined communications format. The controller first verifies that the peripheral device supports a second predefined communications format in addition to the first predefined communications format. Compared to the first format, the second format utilizes messages with greater compression, i.e., an optimized bit stream ("OBS"). The controller next sends the peripheral device a number of commands, including a command of the basic command set accompanied by an OBS enable code. In the case of a write operation, the controller also sends the peripheral device an encoded dataset having the second predefined communications format and representing an underlying unencoded dataset. Although the basic command alone would alert the peripheral device to the transmission of uncompressed data, the presence of the OBS enable code signals a compressed dataset. The peripheral device receives the encoded dataset and, resulting from the received OBS enable code and the command of the basic command set, processes the encoded dataset to obtain the unencoded dataset. In the case of a read operation, the controller receives an encoded dataset, in the second predefined format, from the peripheral device.
摘要:
A computer system automatically senses characteristics of diverse peripheral devices connected to a common communications port, and automatically maximizes the communications speed with the devices. Coupled in daisy chain fashion to the communications port, all peripheral devices receive every signal issued from the controller port, each device responding only to signals addressed to that device or signals addressed to a universal address. The controller first receives an identifier from peripheral devices attached to the controller port. The controller then interprets the received identifiers to determine a maximum communications speed for each device. Next, the controller and the attached peripheral devices are configured to communicate at the maximum communications speed of the slowest device. This guarantees that all messages sent by the controller are compatible with all peripheral devices. Devices subsequently coupled to the communications port are considered by the controller, and the port and other devices are reconfigured as necessary to ensure the fastest possible communications speed.
摘要:
An apparatus and method for using a single, multi-purpose chip for translating a personal computer format or protocol (such as ISA, MCA, PCMCIA or PCI formats) to an output format such as the IBM 5250 format or TWINAX.