Maximizing End-to-End Throughput in Image Communication Systems

Summary

We describe two systems designed and constructed in the Radiology Department of the University of Arizona.

The first system is a high-speed experimental network that is optimized for transmitting radiologic images. The XFT (eXperimental Fiberoptic Token ring) is a fiberoptic-based network that provides a raw band width of 500 Mbits/sec. Various design considerations have allowed us to project a buffer-to-buffer transfer speed of over 300 Mbits/second. We are presently testing transfers in loop-back mode. Using simplified protocol processing we have attained a transfer rate of 400 Mb/s. The XFT project includes the protocol specification and implementation of both the network interface hardware and software.

The second project is a 64 MByte memory board of novel design which we have installed as an upgrade to the Arizona Viewing Console (AVC). This memory board borrows several techniques generally applied to Central Processing Unit (CPU) design to speed operation. For instance, the triple-ported image memory is supplied with caching for each access port. Write-through data cache and preemptive data pre-fetching are also realized.