The mini-micro connection

The office of the future is defined. It is a work station dominated by a micro computer which is in communication with more powerful computers, large disks, printers, and other equipment which can be shared. The large computers, disks, printers, and all the rest already exist. Micro Computers or desk top computers already exist. There are only two steps left in realizing the office of the future. One step involves electronics; establishing high speed communication between the desk top computer and all of the other equipment. The second involves programming; defining and developing coherent software systems. This paper is about the way in which these two problems were handled by the department of political science at the university of Iowa. Weeg Computing Center provides academic computing services for the University of Iowa. They do this with a collection of computers; there is an I.B.M. 370, 5 Prime 750s, 4 Hewlett Packard 2000s, and a Vax. There are also disks, plotters, printers, and the whole panoply of equipment one expects in a university computing environment. In addition, a Gandalf communication system makes it possible to access any one of these computers at speeds up to 2400 bits per second. These facilities are normally accessed with the aid of one of the approximately 750 terminals on campus. With the support of Weeg computing Center the department of political science convinced the university administration that it would be worthwhile experimenting with desk top computers for an entire department. Money was made available, and 37 computers were purchased. Which brought us to the two problems: high speed (in this case 2400 bits per second) communication; and a coherent system of programs. Commodore 8032s were purchased, and this meant that we needed an interface which would translate into the serial signal the Gandalf system used. Several interfaces were available commercially, but we could not make any of them work at 2400 bits per second. Nor could we get the terminal emulator programs available commercially to print the screen at 2400 bits per second. The dominant speed in micro to larger computer communication is 300 b.p.s., fast means 1200 bits per second. An interface board was designed by the electronics shop at the University for us, and a machine language program was written which would handle sending and receiving at the requisite speed. In principle this seemed a straightforward task. In practice there was a stream of nitty gritty problems that seemed as though it would go on forever. But it was done. Three design considerations dominated the creation of the software system. One, it had to be as simple to use as possible. Half of the potential users had never used a computer before. That implied that the system must be as automatic as possible. Two, it had to, initially, provide a terminal to each user plus handle word processing and electronic mail for the department. Three, it had to allocate tasks between the desk top computers and the Weeg supplied computers in a way that, within reasonable bounds, maximized the work done on the desk top computers and minimized use of central resources. Two features of the system illustrate our attempt to make it as easy to use as possible. First, signing on to the central computer is almost automatic. Each person's copy of the machine language program contains their four codes required to sign on to the system. The individual can send these codes by pressing the control key and the up arrow or programs developed for this system will automatically send these codes. Signing off is equally automatic. When the Prime on the other end has finished sending or receiving a program or data it automatically signs off. Second, all choices are made from two lists. One list is on the Prime, and the other list is embedded in the software used on the CBM 8032. Physical contiguity of choices reduces the amount of recall necessary to use the system. A good screen based text editing program enhances one's ability to put words together. It does this by making it easy to write and revise. However, there are many tasks, in addition to writing and revising, that one needs to be able to carry out with the document being written. You must be able to save and recall the text. It is very nice to be able to append a second file to the one being written. It is very nice to be able to save a segment of the file being written. And the text must be sent to be printed. All of these operations can be performed with the aid of the list of commands in the text editing program. One presses 's' and gives a file name; the programs do the rest. In addition, one would like to be able to look at a list of files that have been created and saved, delete files that are no longer needed, transfer a file to the disk storage area of a collaborator for his or her review, send a file (program or program control information) to the batch processing system, and send a file directly from the disk to be printed. All of these tasks can be performed using the list of commands on the Prime. Most of the operations one can imagine wanting to perform on a text file can be accomplished with one of the two lists. That makes the system easy to learn; it provides coherence. In this system the Prime serves as the storage device and the medium of communication. Programs and text files are stored on the Prime disk; there are no disks for the desk top computers. In addition, sending a file to be printed or sending a file to a collaborator plus electronic mail are handled by the Prime. The desk top computers handle the writing and revising which is done with a program written in BASIC to run on these computers. Since writing is an exceedingly important part of the job of academics the computers are on all the time. But most of the time they are not on to the central computing resources; they are working as stand alone computers. When you walk up and down the hall in the department of political science you see lots of computers going. Writing has become much easier. And getting a final document produced has never been as easy or as fast. The mini-micro connection works.