Critical Path Analysis

ZX Computing

WE TAKE A LOOK AT ONE OF THE LEADERS IN THE ZX81 BUSINESS SOFTWARE FIELD - HILDERBAY LTD. Hilderbay produce a number of splendid software packs for the ZX81, including Stock Control and Payroll, and their follow-up service and documentation is an object lesson in how professional software should be presented. All programs come complete with an extensive instruction booklet. Hilderbay also offer a backup service, and will replace programs made obsolete by legislation changes. We'll look at their range program by program: Financial Pack 1: This pack has three programs, LOAN, which - for a loan repayable in equal instalments - computes one of the following in terms of the other three, principal, number of payments, instalment and interest; VAT, which works out, and displays neat tables and running totals, as you enter information from a mixture of bills with and without VAT at different rate; and MORTGAGE, which can be used to get answers to such questions as "How much longer will your mortgage take to repay if you pay £25 less per month?" and "How much of your latest payment went towards interest?" Budget: This program keeps track of expenses for up to 50 headings over a year. For each heading, a budget can be entered at any time. A second version of the program is available, which handles the information in a different manner. Both versions have a facility to trigger the printer for a permanent record. Both versions can be used for private or business purposes. VAT is not included explicitly, but can be handled if required as one or more separate headings. Critical Path Analysis: This program allows the user to apply the critical path analysis technique to any projects which consist of a well-defined set of activities which may be started and stopped independently of one another and must in some cases be performed in a certain order. Michael Levy, head of the American firm Mindware, which is concentrating on providing business applications software for the ZX81 in the US, said that the CPA program from Hilderbay was one of the best he had seen for any system - and he added that he'd seen a large number running on a wide variety of machines, from IBM mainframes down to pocket computers. This program for the ZX81 will deal with problems including up to 500 activities in 16K. If you buy one of the larger memory units available, you can easily deal with many thousands of activities. Payroll: This program which, like all the others, is supported by clear and useful documentation and comes with a followup service, allows employers to keep and update pay records for up to 30 employees. The basis can be weekly, monthly, or any other time interval you choose. Mike Salem, head of Hilderbay, has rightly concluded that many people who use the ZX81 in their businesses may have no knowledge of, and little interest in, computers as such, but still want to be able to use the programs without trouble. This program was designed to cater for these people. You can, if you like, write the results by hand on the usual cards, rather than using the printer. As well, you can always revert to doing it all by hand if you like. You won't become dependent on the computer. The program is designed to be saved after each use, thus saving the current variables on tape, then run next time with the command GOTO 1, rather than RUN. The current program being sold by Hilderbay is, so to speak, obsolete, because of tax and other changes, but those having earlier versions wilt be supplied with up to date versions. This fact shows the attention Mike Salem has paid to ensuring that he provides a proper software service, rather than just running a "post the cassette and run" operation. ll payroll programs, and not just ones sold by Hilderbay, will become obsolete in 1983/84 due to legislative changes which were due to come into effect in 1982/83 but were postponed. The rules themselves will then change, not just the numbers. Until then, however, you can work out your payroll requirements without problems, knowing that if - in the meantime - the numbers change again, Hilderbay will change your program for you. The Payroll program caters for all pay levels and all tax codes consisting of a number followed by a letter (such as 214H). National insurance contributions may be nil, standard rate, reduced rate or whatever, and there is even provision for contracted-out employees. The program will 'watch' what you're doing, and query some input if it believes you are making an error. It is impossible to pay one employee twice in one day period, for example. Although the program is easy, and self-explanatory to some extent, Hilderbay will provide training in its use if you want it. Stock Control: There are two programs on this cassette, one designed to hold a relatively large amount of information about a great many lines. "Stock I" will produce lists by supplier, by type, of understocked lines, or of all lines. Lists may be total or may cover only a certain range of the alphabetical lists. Lists are always displayed on the screen, and are printed if the ZX printer is connected. The program occupies 9K, leaving a fair amount of the 16K for data. "Stock II" identifies stock lines by a numeric code in the range zero to 65,000, storing the stock level for each line. You can handle more than 2000 lines with 16K. Both of Hilderbay's stock control programs are fairly easy to use, and allow lines to be entered or deleted at any time. As can be seen from the above, Hilderbay have an extensive range of business software. Clive should be pleased that Mike Salem, and others like him, are doing their bit to convince the world that the ZX81 is more than a toy. Other distributors of ZX business software should be grateful to Mike Salem for showing how well it can be done.