Praet July 1981 OMPPtingVolume 4 Issue 7 winning chools and usiness eviews: ompucolor II xplorer 85 aper Tiger and pinwriter Holiday ccounting et virtual 11"".16 emory MicroCentre introduce System Zero Basic System Zero £587 System Zero/D with DDF £2355 The System Zero is a small computer especially designed for dedicated applications. It is particularly useful in process control situations. In the basic model you get Cromemco's famous Z -80A single card computer, 1 k of RAM, 4k of ROM, Control Basic, and an New System attractive cabinet. The motherboard provides Zero Computer with quad -capacity DDF disk drive. The system 3 extra card slots on the S-100 bus, for includes built-in diagnostics for a quick system test of memory, controller and disk drives tailoring the system to particular applications. System Zero/D The basic model is designed for ROM -based This special version of the System Zero programs, but it can be expanded by the has 64k of fast RAM, and a model DDF dual addition of memory and I/O cards. It is fully disk drive. It includes two double -sided compatible with all Cromemco peripherals, double -density 5 inch disk drives giving a including floppy disks and hard disk systems. total of 780k bytes storage; and RDOS-2, a Suitably configured the System Zero can run new resident disk operating system with any Cromemco operating system or software terminal and printer drivers, and self -test package. diagnostics. The System Zero/D is an exceedingly inexpensive development computer ideal for setting up dedicated applications to run in the basic model. It will support Cobol, Fortran IV, Ratfor, Structured Basic, Lisp, RPG II, Word Processing, DBMS, and the full range of Cromemco's business applications software. Operating system The System Zero/D will run any Cromemco operating system provided sufficient memory is available. The mimimun configuration of 4k ROM runs control Basic; with 64k RAM the system will run RDOS-2 or CDOS (compatible with CP/M); At the recent UK launch of the System Zero Computer, Cromemco's Technical Director and with 128k the Zero/D will Roger Melen presented a System Zero/D with 128k memory running Cromix. Here he is run the Cromix system (based on seen discussing the system with MicroCentre Director Andrew Smith (right). Unix). For p Cromemco... call the experts Complete Micro Systems Ltd., MicroCentre 30 Dundas Street Tel: 031-556 7354 Edinburgh EH3 6JN Circle No. 101 2 CONTENTS 41Editorial / What price software? 42Feedback / ZX-81 complaint and praise; raising money for refugees; micros in medicine; alternative history of microcomputing 46Printout / Government gives away Prestel sets: battery -backed RAM; second-hand micromarket; CP/M on Pet 55Telesoftware / Martin Hayman reports on teletext art Twinning schools and business-page 57 57Twinning / We propose a revolutionary scheme for bringing education and business together Editor Q Peter Laurie 58Explorer 85 / The modular system from Newtronics Assistant Editor Duncan Scot 65Compucolor II / Mike McDonald tests the colourful features of this Staff Writer computer and tries a selection of its software Bill Bennett Production Editor 7hProkit / The professional software kit for the Pet Toby Wolpe Prestel Editor Paper Tiger / Printer review by Chris Bidmead Martin Hayman 74 Editorial Secretary Tracy Ebbetts 75Spinwriter /A top-quality printer from NEC Consultants Technical Nick Hampshire 77Business software / A new series by Charles Somerville on how to Software Mike McDonald write your own business software Editorial: 01-661 3500 Q Advertisement Manager 79Applications / How a seaside camp resorted to an Apple to handle its David Lake accounts Advertisement Executives 82Star system / The first part of a complex space game by Bob Merry Philip Kirby Ken Walford Investment / Manage your capital investment with this program Advertising: 01-661 3021 91 Midlands office: David Harvett 021 -356 4838 94Education / Rex Tingey presents a program for schools Northern office: Geoff Aikin 06 I -872 8861 98Virtual memory / JA Forbes explains how to create that extra memory Advertisement Secretary Mandy Morley Publishing Director 101Algorithms /MarkWalker analyses several sorting algorithms Chris Hipwell Published by IPC Electrical electronic 105Z-80 Zodiac PressLtd.Quadrant House. The Quadrant, Sutton, Surrey, SM25AS. Tel:01-6613500.Telex/grams 106ZX-80/81 Line-up 892084 BIPRESG. Typesetting and artwork by Bow- Towning Ltd. London EC I Printed by Eden Fisher Ltd. Southend- 108Tandy Forum on-Sea Distributed by IPC Business Press (Sales and Distribution) Ltd, Quadrant 1096502 Special House, The Quadrant, Sutton, Surrey SM2 5AS. Subscriptions: U.K., £10 per annum; 1 1 1Pet Corner Overseas £16 per annum; selling price in Eire subject to currency exchange fluctuations and VAT; airmailrates 113Apple Pie available on application to Subscription Manager, IPC Business Press (S & D) Ltd, Oakfield House, Perrymount 114Micromouse Road. Haywards Heath, Sussex RH 16 3DH. Tel 0444 59188. © IPC Business Press Ltd 1981 119Book Reviews ISSN 0141-5433 Would-be authors are welcome to send articles to the Editor but Pet Graphics /Part 2 of Nick Hampshire's series PC cannot undertake to return 120 them. Payment is at £30 per pub- lished page. of bubble and other sort routines Submissions should be typed or 125Sort times / A comparison computer -printed. Hand-written materialisliable to delay and error. 132Microcomputer Buyer's Guide Every effort is made to check articles and listings but PC cannot guarantee that programs will 147The Hexadecimal Kid / Page 10 of Richard Forsyth's parable run and can accept no respons- ibility for any errors. Prestel page number 357 PRACTICAL COMPUTING July 1981 3 IF YOU DON' 1 WWI A NO RD PROCESSRIG DOCUMENT 7 HFIT L 1:11:1113 1 TH.L; YOU NEED A PRINTER THAT PRINTS LIKE THIS. The more your system can do, the better your what we sell. That means excellent service to terminal should be. That's why, if you're adding the OEM and the end user and one of the best text editing capability to your data processing supplies programs in the business. system, you should also think about adding a So if you're getting ready to upgrade your quality daisywheel terminal to replace the matrix system, then it's time you upgraded your terminal you're using now And the best -quality printer as well. To a Qume. terminal you can buy is one by Qume. Ask about the NEW Sprint 7 and 9 models. A printer for every application. For more information LIMB Eu No matter what application you choose, contact your AUTHORISED DISTRIBUTOR Qume makes a printer to fit it. Like our Sprint 5° KSR and RO, which ACCESS DATA COMMUNICATIONS LTD., have achieved the reputation for being the 228 High Street, Uxbridge, Middlesex. Tel: (0895) 30831. easy -to -use leader in letter-perfect terminals. DAISY TERMINALS LIMITED, Bridge Road, You can have 50 different typestyles to use with Haywards Heath, West Sussex. Tel: (0444) 57546. it, including APL, scientific symbols and FACIT, Maidstone Road, Rochester, Kent. international character sets. Tel: (0634)401721. And there's the Sprint 5 Wide -Trackwith ISG DATA SALES LIMITED, Unit 9, Fairacres Ind. Estate, RS -232C interface. The first character printer Dedworth Road, Windsor, Berkshire. Tel: (07535) 57955. data terminal in the world capable of handling ROHAN COMPUTERS LIMITED, 52 Coventry Street, paper up to 28 inches wide. That's a full 264 - Southam, Warwickshire. Tel: (092681) 4045. column printing area. Sprint 5 Wide Track adds an entirely new dimension to the printed word. The best backup in the business. Not only do we make the best printers, but Qume (UK) Limited Tel: (0734) 584646. Telex: 849706. we also provide the best support to back up A British Company of ITT I 111111111111111.1111111111111111111 -411111;°. e11 I 1111.1P Circle No. 102 PRACTICAL COMPUTING July 1981 4 Corned Approved Dealers Belfast 0 & M Systems 95 Dublin Road Tel: 0232 49440 Birmingham Byteshop Computerland Ltd 94/96 Hurst St, B5 4TD Tel: 021 622 7149 Cambridge Cambridge Computer Stores 1 Emmanuel St. CB1 1NE Tel: 0223 68155 Cornwall Benchmark Computer Systems Ltd Tremena Manor Tremena Road St Austell, PL25 5GG Tel: 0726 610000 Dublin Lendac Data Systems Ltd 8 Dawson St Tel: 0001 372052 Glasgow Byteshop Computerland Ltd Magnet House 61 Waterloo St, G2 7BP Tel: 041 221 7409 Leeds Holdene Ltd Manchester Unity House 11/12 Rampart Road Woodhouse St Tel: 0532 459459 London Byteshop Computerland Ltd 324 Euston Road London W1 Tel: 01-387 0505 Digitus 9 Macklin Street Covent Garden WC2 Tel: 01 405 6761 Jarrogate 67 Tulsemere Road, West Norwood, London SE17 Tel: 01-670 3674 Manchester Byteshop Computerland Ltd 11 Gateway House Piccadilly Station Approach Tel: 061 236 4737 NSC Computers 29 Hanging Ditch Tel: 061 832 2269 Newbury Newbear Computing Store 40 Bartholomew St Tel: 0635 30505 Nottingham Byteshop Computerland Ltd 92A Upper Parliament St, NG 1 6LF Tel: 0602 40576 Sheffield Hallam Computer Systems 451 Eccleshall Road, S11 9PN Tel: 0742 663125 Southampton X itan Systems 23 Cumberland Place. SO1 28B Tel: 0703 38740 Sudbury Eurotec Consultants Horizon Hard Disc addsa new Holbrook Hall Little Waldingford Tel: 0206 262319 Warwick. dimension to cost effective Business & Leisure Microcomputers 16 The Square Kenilworth data processing Tel: 0926 512127 Watford Lux Computer Services 108 The Parade High Street Watford WD11 2AW Tel: 0923 29513 With its parentage already established as the even more in reduced operating costs and Comart Microcomputer dealers proven performer in its price range, North Star's efficiency. are located strategically throughout the country to give Hard Disc Horizon is set to break new barriers in Add to that the new North Star Application support, guidance and cutting the cost of data storage and retrieval. assistance. In the event of Software, Word Processing, Information difficulty contact Comart direct.