[Indigo]<Voice>Documentation>comm.activityreport!1

As dependence on inter-machine communication has grown, conventional use of home computing facilities (simple terminals or stand-alone personal computers) have become less valuable for professional workers. The objective of the home computing activity is to extend the communications capabilities of Cedar so that members of the staff can use Cedar on Dandelions in their homes.

A report on external communications was prepared as part of the deliberations of a PARC-wide committee on communications from Internet sites to homes and to remote laboratories. This report addressed the availability and economic feasibility of various means for medium and high-speed communications among sites. [E. Fiala]

It appears that we will not be able to afford speeds higher than 4800 bps between the home and the office for several years. One way to increase the effective data rate of such slow communications lines is to send the data more efficiently by employing compression algorithms. We have looked at two kinds of data compression (compressing packet headers and compressing complete files) with encouraging results. In particular, a textual substitution method based upon a paper by Ziv and Lempel provides nearly two to one compression for program text files in Cedar. This algorithm can be implemented efficiently enough on our workstation machines to be practical. [E. Fiala, D. Greene]

A report on hardware and software configuration options for Dandelion home workstations was produced. This report includes a careful economic analysis supporting the claim that increased productivity can be obtained by taking workstations home. It also proposes a reasonable initial configuration for these home machines. [E. Fiala]

We have obtained a small number of Dandelions and modems for use in a pilot program. The required communications software and system installation procedures will be developed in the laboratory using these machines, which will then be installed in a few selected homes on an experimental basis. Further expansion of this program will depend on the success of the pilot study.

The Dicentra is a processor designed to function as a controller for communications and device control applications. The Dicentra executes the PrincOps instruction set, can be connected to commercial devices that have standard Multibus interfaces, is compact, and has proven to be exceptionably reliable. It was designed partly to fill existing service needs within research, and partly as a prototype for a kind of utility processor that has not yet been included in the Xerox 8000 series product line.

In June and July orders were accepted for a build of approximately 30 Dicentra processors, most of them for use as Internet routers and terminal concentrators. These machines are being produced by the Electronic Model Shop. Recent development activities include the final debugging of a telephone line control board, and the design, development and test of a high-speed (1.5 Mbps) communications controller for the Dicentra. [H. Murray, J. Henning]

We will continue to work with the Electronic Model Shop in the production of the Dicentra processors, which should be delivered during the first quarter. Activities will include providing training for technicians who will have to maintain the machines. Dicentras outfitted with the new high-speed boards will be used in conjunction with leased digital lines and possibly private microwave radios to provide 1.5 Mbps connections among Palo Alto internet sites.

A prototype facility for manipulating and editing fragments of recorded voice, much as one would manipulate a text string, has been developed and tested. Based on this Voice Rope prototype, a complete design for the storage and manipulation of recorded voice has been produced. In addition, the reliability and maintainability of the existing Etherphone system has been improved. An RPC implementation in Interlisp that will allow access to the advanced Etherphone capabilities from Lisp workstations is nearing completion. [D. Swinehart]

This year should see significant progress in the exploitation of the Etherphone system. Two or three people will be joining the project early in the year, with the goal of designing the remaining unfinished components of the system (primarily advanced telephone functions and a flexible programmer’s interface) and completing a significant part of the implementation during 1985.

Any Xerox employee who has access to the Research Internet can communicate via electronic mail with colleagues in universities and other industrial research establishments by means of the Arpanet (which in turn provides access to other networks, such as the recently-established Computer Science network (CSNet)).

The connection between the Research Internet and the Arpanet has for years been provided by programs running in our Maxc II timesharing machine. Maxc was retired from service in December. The Arpanet file transfer, terminal emulation, and electronic mail protocols were transferred to a recently-acquired VAX computer and to dedicated Internet servers. A committee of computer researchers at PARC participated in these activities. [J. Larson, H. Murray, W. Jackson]

PARC has recently become a member of the CSNet consortium. At present, access to CSNet sites is still exclusively through the Arpanet. CSL is providing the official liaison for both the Arpanet and the CSNet. [J. Larson]

Apart from the development of Dicentra, recent Internet activities directly related have been confined to maintenance, support, and consultation. In particular, the Grapevine mail transport system has required substantial manual intervention, primarily due to overloaded servers and telephone lines. In addition to providing this service, we have been encouraging organizations to replace Altos with Dandelions, Dolphins, and Dicentras, both as Internetwork routers and as Grapevine servers. We have been assisting with these transitions as they occur. [H. Murray]

Support for Grapevine and the Research Internet will continue. In addition, we intend to implement the NS-8000 communications protocols in Cedar beginning early in 1985. A plan to design a new set of protocols addressing known shortcomings in the existing ones is also under serious consideration.