THE XL/2000

XL/2000 Hardware Description
An XL/2000 is a multiple processor system that provides very high data throughput and can be configured to perform a multitude of functions. The personality of the node (local, remote or combination local and remote) is achieved by selecting the appropriate features and software. The physical cabinet is 32" high, 12.5" wide, and 27" deep. Each cabinet contains a card cage, redundent power supply, power distribution unit, fans, motherboard, operator control panel and miscellaneous internal cables. 

Each XL/2000 node is configured with a diskette drive and a fixed disk drive. The floppy drive is used for initial loading of PIXNET-XL software and unit configuration, the running of stand-alone hardware diagnostics and stand-alone utilities as well as being used as removable media for initiating diagnostic memory dumps or back up of configuration files. The fixed drive is used for permanent storage of node software, node configuration parameters, maintenance information, and other pertinent node and network data.

Each unit can be configured with up to six processor boards, two global memory boards, and two channel interfaces. The channel interfaces may be either local or remote, each using two slots in the card cage. All processors are independent of each other, and communicate with each other and with global memory across a common bus. The XL/2000 card cages is shown below.

XL/2000 CARD CAGE

PIXNET-XL Software
PIXNET-XL software is based on the Open System Interconnect (OSI) model for linking incompatible systems or devices, developed by the International Standards Organization (ISO).

The most significant feature of the software is a unique approach called channel/device emulation. The local control unit fully emulates the device at the host channel and the remote control unit recreates the channel for the device - all with full compatibility for error recovery procedures, channel program logic, and message handling.

All software developed for the PIXNET-XL family is extremely modular and written in high level "C" language. The modularity of design and the utilization of a high level language provide greater maintainability and portability to new hardware platforms.
 
 

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