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AMSTRAD DMP-1 (Amstrad Computer User) | DMP-1 (Personal Computing Today) | PRINTING MONEY (Amstrad Computer User) |
Gareth Jefferson PRINTs #8 and LISTs a few tips... A printer for your computer costs almosts as much as the computer itself, especially when that computer is as modestly priced as the Amstrad CPC464. Before you buy a printer, you have to ask yourself two vital questions: Is it a worthwhile investment? Is the printer I buy the best value for money? Let's deal with the first question first. Irrespective of cost, a printer for your computer must be seen as a tool - a tool that helps you get the best value from your investment and a tool that turns your computer into a commercially viable product. Before you can justify the cost of a printer, you must analyse the ways in which you use your computer. Broadly speaking, there are three main areas of use for home microcomputers - games, software development and business use. If you intend to use your computer only for games, you may not be able to make a strong case for buying a printer. But what a waste that would be! The games programs available for the CPC464 will provide hours and hours of entertainment and challenge, but that's only scratching the surface of the 464's capabilities. What do you do if you want to develop your own games? (remember, there's a £2,000 prize for winning games entries - see page 29). What do you do if you want to use your CPC464 as a word processor using the AMSWORD software package? Easy screen editing and formatting of letters and documents is not a lot of use without being able to print the results! What do you do if you want to make your business budgeting or domestic financial management more profitable if you can't keep a permanent record of the results? And then there's writing your own programs. All these activities need a printer. Let's see why. Program development Multi-million pound businesses have been based on the development of computer software, and Amstrad User Club members can also win big cash prizes for successful programs. The CPC464 comes with an advanced version of BASIC, the world's most popular and easiest programming language. A powerful Z-80 assembler is available as a low cost option. So too is the famous Pascal programming language, favoured in leading universities and software companies throughout the world, and DR Logo, the ‘artificial intelligence' language that's paving the way towards truly intelligent computers. With these programming tools, the CPC464 owner has everything necessary to develop the computer software demanded by today's dynamic and expanding computer market. These tools allow owners of the Amstrad CPC464 to write software not only for the 464, but also for the many millions of other Z-80 based computers already in use world-wide. Before you can reap these benefits, however, there is one prerequisite. A printer. Developing a fully ‘debugged', working program involves a certain amount of trial and error. Even the world's most famous programmers - people such as Dr. Niklaus Wirth of Zurich who developed the Pascal language that forms the basis of Amsoft's HiSoft Pascal - cannot write programs that are 100% error free. To some extent, you can check your programs as you develop them on the computer screen. But, ultimately, you need a permanent record -hard copy in computer jargon - and that means a computer printout. Without a printer, you can forget serious software development, whether it's a commercial package for sale or a program you are writing for your own entertainment. Printers and the Businessman Businessmen tend to use computers either to help in financial projections, using spreadsheet programs such as Amscalc, or as word processors using word processor software such as Amsword. In both cases, paper printouts will be needed for permanent records. The best type of printer for business applications depends partly on the nature of the task. Very high print quality may be needed in letters to certain clients, and in that case the printer will have to produce ‘fully formed' letters in much the same way as a typewriter does. Computer printers of this type are called ‘daisy wheel' printers. But daisy wheel printers are both slow and expensive, so most people opt for the faster, less expensive dot printers. Dot printers have other advantages over daisy wheel printers apart from speed and price. Because the letters are formed from closely spaced dots, many models allow the printing of user defined graphics characters, graphs, pie charts and so on. These advantages are appreciated by businessmen who often want a permanent record of the computer's screen output (called a ‘screen dump'). Ordinary daisy wheel printers cannot produce graphics and can only print the pre-formed characters on the wheel. Various styles of printout: 1)Daisy wheel printer 2)Philips Word Processing One of the most popular uses of home computers is for ‘word processing'. Word processor systems comprise a computer plus word processing software that allows the computer to act as an intelligent typewriter. The computer keyboard is used like a typewriter keyboard, but the software allows the words in the document to be deleted, moved about or added to at will. Corrections and re-thinks no longer involve re-typing the whole document. Nearly all the articles you see printed in the computer press, including this one, were produced with the help of wordprocessor software, and businesses throughout the land, from solicitors offices to banks and estate agents, use word processors to increase their productivity. Amsoft's Amsword allows you to do the same, but again one item is a must - a printer. The DMP1 is more than an ordinary printer. It costs less than most - £199 retail, £169 to club members - and yet offers more It's fast, inexpensive and versatile. It prints 80 columns - that means a full 80 characters across the page -and prints characters using a 5 x 7 dot matrix. Using ordinary printer paper (expensive electrostatic paper is not needed), it prints characters using a special ‘impact' technique. The DMP1 printer takes standard perforated fan-fold paper and can print ‘dot graphics' for screen dumps as well as high quality character printouts. How printers work The first computer printers worked just like Telex printers. Codes for each character were sent to the printer, and these codes determined the sequence of printing bars popping up to hit the printing ribbon against the paper. Things have advanced from those early printers to create products such as the DMP1. Modern printers use a number of techniques that boil down into two basic printing methods - impact printing and non-impact printing. Non impact printers (the DMP1 is not one of them) usually involve the electrostatic transfer of printing marks from the print head to specially treated paper. The marks are, in effect, burnt onto the paper. Another non-impact technique sometimes used in high speed, expensive printers is the so-called ‘ink-jet' technique. This method involves squirting a jet of ink droplets at the paper that dry on contact. The method is silent and reasonably fast but very expensive. x An even faster - and yet more expensive - technique utilises laser printing. Laser printers work something like photocopiers. A high power laser beam is scanned onto a roller and causes it to become electrostatically charged. The roller then picks up ink powder and transfers it to the paper - all at very high speed. Laser printers can print several thousand lines of output a minute, but the equipment is cumbersome, expensive and beyond the means of the home computer user. Impact printers The slowest printing technique of all involves the use of so-called ‘daisy wheel' printers. These printers use a disc constructed like a flower, where each ‘petal' has a reversed letter or digit moulded into the end. When a code corresponding to a letter or digit comes from the computer to the printer, the ‘daisy wheel' is rotated until the appropriate character is in position against the printing ribbon. An impulse is then sent to a hammer that hits the ‘petal' against the ribbon to print the character on the paper. Dot matrix printers By far the vast majority of computer printers use a more advanced technique whereby one or more small pins is ‘fired' against the ribbon to print a series of dots. Such printers are called ‘dot matrix printers'. Special software built into the Amstrad DMP1 printer interprets the character codes that are sent from the computer and ensures that each dot is printed on the paper in exactly the right position to create a single character. Each character, then, is made up of a matrix of tiny dots - up to five dots across and seven dots down in the case of the DMP1. The illustration below shows how this is done. Some dot printers, including the DMP1, incorporate special software routines that allow every dot to be printed under the direct control of the user. This allows user-defined graphic symbols to be printed as well as letters and digits, and makes printing an exact replica of the images on the computer screen possible - a process called screen dumping. The DMP1 allows 60 dots to be printed per inch in the graphics mode. The Final Word Computers can be great fun even without a printer. But to get the most from them, you should seriously consider investing in a printer too. Printers are an essential accessory if you want to develop your own programs, almost indispensible if you want to do financial planning using a spread-sheet program, and word processing without a printer would be like typing without paper. Your CPC464 is provided with an industry standard ‘Centronics' style printer interface, so almost any commercially available printer would work with it, but, like your computer, the Amstrad DMP1 printer would work with it, but, like your computer, the Amstrad DMP1 printer gives more performance for less outlay, and should come right at the top of your list. Whether you want to print out program listings to check for bugs and errors, financial projections, letters to clients or anything else that needs a permanent record of what's going on in your computer, you need a printer! CPC464 USER |
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