The Gazette 1990

JULY/AUGUST 1990

GAZETTE

How do the two operating systems compare from a performance point of view? To explain this we will use an example of someone typing a document on both systems. As the typist presses each key, the computer is continually moni- toring the keyboard to see what key the typist presses, so when the typist presses " W " , the computer interprets this and then displays a " W " on the screen, and so on for all letters in the document. The computer also watches for when the typist reaches the end of a line (by counting the number of letters on a line) and automatically reformats so that the start of the word goes onto a new line. A lot more work is done by the computer as the typist corrects mistakes, displays different parts of the docu- ment and formats the document. Now let's assume that there are five typists. On a UNIX computer all this work is done by the one computer. This means that: — there are five copies of the word processing program in memory; there are five different docu- ments in memory; the computer cycles to each typist and gives each a slice of time to keep his screen up to date with his typing; the limiting factor is the memory size of the computer and the number of typists. On a network each typist has a whole PC to himself. This means t h a t : - there is less work being done collectively by each PC; the processing is going on inde- pendently and simultaneously; there is no delay on one computer keeping all the other typist's screens up to date as each PC keeps its own screen up to date; the limiting factor for each typist is the speed of his PC; What happens when the typist decides to write the document to disk? Here both systems have approxi- mately the same amount of work to do. However, new limiting factors come into play. On a network it is the speed with which the PCs can send data to the file server and the speed with which the file server can write to disk. On the UNIX computer the limiting factor is the speed with which it can write to disk and the number of users using the computer re- quiring their screens to be refreshed. One person writing to disk on a

them some of the largest firms in Dublin) who use networks and use them very well and efficiently and are very happy with them. Indeed, they would be very offended if anyone thought they experienced any of the problems outlined by Mr. Lanigan. On any system, single- user, networking, UNIX or any other, you will have chaos if everyone is allowed to operate in ignorance without structure and discipline. When I want legal advice, I go to my solicitor. When I want account- ing advice, I go to my accountant. When I want computing advice I ask my colleagues, whom I know to be independent. However, my experience, shows that less than 2% of solicitors consult with an independent computer consultant and that most solicitors choose their computer systems from re- commendations by other solicitors. " . . . less than 2 % of solicitors consult with an indapandant computer consultant This is not entirely wrong, but your plans for your firm are not neces- sarily the same as your colleague's plans for his. On a recent visit to the Cebit Computer Fair in Hanover, I was very interested to learn that the majority of German lawyers pur- chasing computer systems (not simply PCs for word processing) were going for networking solu- tions rather than UNIX as they believe simply that one processor could not work as fast as several processors on a network. They are planning for the day when every person in the firm will have a PC or terminal on his desk, from the most senior partner to the most junior clerk; when they can take their work home, to court, to a client or abroad on a portable PC and simply report back to base over a modem whenever necessary. Despite their high spending power, less than 10% of German lawyers have gone beyond the PC word processing stage as yet. However, with the coming of 1992 and the social charter, German secretarial costs are set to rise and as a conse- quence office automation systems are becoming more common. The systems being chosen are on net- works rather than UNIX. * Donal O'Loch/ainn has an M.Sc. in Computer Science from Trinity College, Dublin. He is a computer consultant and specialises in software solutions for the legal profession. His software product TOPS Legal is now installed in 20 firms in Ireland. He is M.D. of TOPSOFT Ltd., Fermoy (025) 32344.

House Hunters A SNAG LIST FROM AN ENGINEER for presentation to your builder is both economical and essential. I also provide reports on older houses, Legal & Insurance Claims & Certificates of Compliance. Phone Colm O'Reilly , B.E. 6280156 network will not affect the typing on another person's PC. However, on a UNIX system the computer has to wait for the physical movements of writing to disk, which is slower than keeping screen displays refresh- ed so there is a degradation in performance whenever there is disk reading and writing on a UNIX computer. Ask anyone which is the best word processor and the answer will invariably be his own. It is the same with operating systems. UNIX users swear by UNIX and networkers do likewise. However, when compa r i ng you must compare like with like. There is no point in saying that a particular network is slow if you have a super fast file-server and the PCs attached to it are slow when the PC's speed is the limiting factor. Similarly, you cannot say UNIX is slow if the computer is not My own view is that networking is the way to go. The range of software is by far the greater and the economies of scale mean less expensive software. If the file server is fast and the PCs are chosen carefully for their use, the unit user cost is less. Also you can build now for a ne twork by choosing stand-alone PCs and coping with the integration problem in the short term. (I have just ordered a networking system using a Digital VAX mini computer as a file server with three 80286 single floppy workstations). In a recent article in this Gazette Mr. Frank Lanigan was very dis- missive of Networking systems claiming they were single user in concept and that everyone using them acts independently. This is completely untrue as I am aware of several firms of solicitors (among " M y own view is that net- working is the way to go." fast enough or there are too many users competing for the resources of the one computer.

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