| ★ APPLICATIONS ★ CREATION GRAPHIQUE ★ GOS (GRAPHICS OPERATING SYSTEM) ★ |
Graphics Operating System (8000Plus) | The PCW picture show (Popular Computing Weekly) |
GOS is a graphics programming utility for the PCW machines, released by Mirrorsoft. David Lawrence reports One of the benefits of writing complicated programs the nght way - with each different function separated out into a neat unit of code - is that you end up, having finished your package, with a large collection of working routines which you can quickly incorporate into the next product, and the next, and so on ad infinitum. Of course, if you happen to be writing a desk top publishing package which needs to be able to handle a wide variety of graphics, windows, fonts of different kinds and all of it controlled by pop-up menus, you might just look at the bits and piecos you have written and decide that what they really add up to is a complete set of routines for anyone who wants to add graphics, fancy text and pop-up menus to their own programs. To be specific, if you were Mirrorsoft and just putting the finishing touches to Fleet Street Editor for the PCW 8512. you might just decide that the bits and pieces that made up the program were so good that they should be packaged and sold in their own right as the PCW Graphics Operating System So it was that GOS was born and is about to be launched into the PCW market place. The first question that comes to mind on seeing GOS is. "why bother?", when every PCW comes equipped with a version of Digital Research's GSX (Graphics Extension) system, allowing a range of graphics and text to be adcled to displays Like GSX. GOS is grafted on to existing programs and languages, so it is not a new language but a tool which can be controlled from other languages and programs. The problem is that unlike GSX, GOS has not been around for years and so doesn't have a large body of programs which make use of its capabilities to enhance their displays. These would be difficult points to answer if Amstrad and Digital had bothered to supply more than a token GSX system as pan of the standard package. The PCW's GSX. though it works satisfactorily, is completely out of date and. compared to other versions of GSX around, the PCW version is stripped down to the bare bones of what it is possible to sell and still call it GSX. By opting for such an inferior system Digital has effectively left the field to others - the first full-feature graphics operating system to establish a decent user base will very quickly become the standard and GOS looks like a very good contender for that position. So what exactly is GOS? Put simply it is an extra self-contained section of code which is grafted on to a program or language in memory You can use the system with any program or language which can be restricted to use only memory below address 49152 (C000h) Once the memory has been reserved, the system is very similar to using GSX. To send commands to GOS. certain values are placed into specified memory locations and then a call made to GOS to carry out the command. That means high resolution for programs written in almost any language available for the PCW. including Mallard Basic, though as with GSX only some 17K of memory is available for programs when Basic is loaded The beauty of GOS is that its self-contained code is impressively fast and the speed with which individual commands are executed is unaffected by the language being used. Of course, there will be considerable differences in speed between, say, a m/c and a Basic program using the same commands, but the GOS commands themselves will execute at the same speed in both.
Despite all these features there are. admittedly, one or two shortcomings compared to the ideal laid down by the GSX concept. Text can be displayed at specified positions but no mention is made of a separate character cursor to allow the current position of text output to be remembered. To create a polyline, or line made up of several sections, would require several commands in GOS but only one in GSX. There is no provision for predefined markers, making the task of creating graphs that little harder. Perhaps most of all, for those selling expensive packages which use more than a standard PCW. GOS lacks GSX s flexibility when it comes to handling output to and input from a wide range of different devices. These, however, are small points when compared to the wide range of functions GOS will carry out and when that range is compared with the severely cut-down GSX available with the PCW -it is unfair to compare the system with a theoretically perfect GSX which simply isn't available to PCW users. Who will buy GOS depends on who needs its graphics capabilities badly enough. It would be wrong to say that the system is easy to learn for the average PCW user Poking values into memory locations and making calls with the Usr command is an unfamiliar process for most people. Having said that, the feel of the system is far more friendly than GSX, with its variety of different arrays to be filled or read Provided that a programmer is prepared to follow the manual for a while, no particular problems should arise. Even so. it is not the kind of product that anyone who would like to create a few pictures for fun will buy. The real market for GOS must surely be anyone who wants to give a program a professional feel at the cost of almost no effort The ability 10 add graphics touches, special typefaces, pop-up menus and dialogue boxes without having to exercise any great skill will surely be an irresistible temptation Of course, the end users of any program based around GOS s capabilities will themselves need to have GOS (or have it supplied with the program) and there is the rub. Mirrorsoft. which is publishing GOS. has to make the decision as to how free it will be with licences to distribute the system along with software that uses it. Without a liberal attitude to distribution there will be no user base, and without a user base there is no point in writing programs to make use of GOS. Perhaps Mirrorsoft should learn from Digital's distribution of GSX In this country, it is possible to get GSX free on a number of machines, including the PCW. What you don't got is a decent manual - that costs you up to C40 extra. The result is that there are a lot of GSX equipped machines to encourage programmers and that all the actual and would-be programmers buy a manual and toolkit - the best of both worlds. The Graphics Operating System would benefit from that kind of faith being shown in its ultimate success, and the majority of PCW ownors would benefit from the quality of the programs that would be produced. David Lawrence , PopularComputingWeekly |
|  |
|
