| ★ HARDWARE ★ PERIPHERIQUES CPC - INTERFACES DEBUGERS ★ MIRAGE IMAGER ★ |
Andy Wilton plugs-in a novel approach to tape-to-disc transfer If you thought having a disc drive meant fast-loading games, you probably reckoned without all those problems of three-inch disc shortages, titles only available on cassette, and the extra £5 a time that disc-based games tend to cost. For those of you who just have to have your lengthy games on disc, the choice has always been one of buying a tape-disc transfer utility or learning some serious machine code. Neither of these two methods are exactly ideal. Tape-disc utilities have a bad reputation for encouraging piracy; and a worse one for simply not working. There's an undeclared war between people who write transfer utilities and people who write turbo-loading routines. The latest games will always stay one jump v ahead, and keeping up with r advances in copier design can get pretty costly. As for the hacking approach; this too has its problems. Even dealing with simple headerless loaders needs a sound grasp of machine code and a pretty good idea of the way Arnold's laid out inside; and as for the latest turbo-loading protection schemes: these take effort, skill and a great deal of. mental juggling. If you're not already equipped for the job, it could be an expensive business too. Just the firmware manual and a decent set of hackers'utilities - Pyradev, for example - could set you back the best part of £50. For the same sort of price, Mirage now offer a third and much simpler solution to the tape-disc problem in the Imager. It handles tricky loaders and other protection schemes with ease because, unlike all the other transfer systems currently available, it's a piece of hardware.
WHAT IT IS The Imager takes the form of a chunky expansion-port module, designed to hug the back of a 464. For the benefit of 664 and 6128 owners the package includes a ribbon-connector so that the unit can stand free of the machine. Also included are a couple of photocopied sheets of paper by way of instructions, and that's it. The most prominent feature of the Imager module is a single red button on the top of the casing. Indeed, aside from the through-connector and the Mirage label, it's the module's only feature. This button is used to activate the Imager when you need it. Plugging in is quite straightforward on the 464, but 664/6128 owners have to be a bit careful. With most expansion-port plug-ins, Arnold finds any connection problems on power-up. The Imager is an unconventional peripheral, however, and a normal power-up screen doesn't necessarily mean all is well. You may well find that, even with an apparently healthy startup, pressing that red button produces the usual bad-connection mess on screen. As ever you have to switch off and plug in again, making sure the metal strips of the connectors line up, and then switch Arnold back on. Repeat this until everything behaves itself. WHAT IT DOES Once the Imager is set up properly you can go ahead and load the game you want to transfer. At this stage Arnold behaves exactly as normal because, quite simply, he doesn't know the Imager is even there. Once the game has reached the point where you want it saved, you just hit the red button and the Imager swings into action. Immediately the game action freezes, and the top two lines of the screen are replaced by the Imager's sign-on message. With most games you'll also find the colours on the rest of the screen go haywire, and quite possibly the display ends up scrolled rather strangely If you now hit on the keyboard the sign-on message is replaced by a prompt and a list of possible commands. The emphasis here is on ease of use. The only options available are Save, Load, Run, New and Cat - all very familiar command ideas. You just type the first letter of the command you want and hit . If you type 'S' for 'Save1 the Imager prompts for a file name, asks which drive you want to save to and then goes to work writing the program to disc. The 'Load command leads to a similar filename prompt, after which the saved game loads in to memory. You can now restart the game where you left off by using 'Run'. As for the other commands; using 'New' before you load the game from its original can save you a lot of disc space, especially on the 6128; and 'Cat' just catalogues the disc -though at the cost of losing any program you had in the memory. There are plenty of possible error messages, but they're mostly self-explanatory and the documentation covers them pretty well anyway. HOW IT WORKS Provided there's room on the disc and you don't make any silly mistakes, the set-up works every time. It's hard to imagine a protection system that could stop the process - conventional turbo-loaders or Lenslok-type systems certainly don't. That's because the Imager works by brute force, and makes no attempt to understand the code that it's dealing with. When you press that red button and choose the Save command, the Imager stores the entire contents of Arnold's memory and the precise state the Z80 is in at the point where the game got frozen. In theory, then, it can make a record of everything about Arnold's state at the point when you pressed the red button, and restore him to that state some time later. Unfortunately, there are some aspects of Arnold's 'state of mind'colours and screen size in particular - which the Imager can't record. This meant that Ghosts and Goblins, while playing fine, adopted a very funny set of colours after imaging. As for Starstrike II, screen size problems made the imaged version unplayable. Mirage are working on a replacement ROM to get round the screen-size problem, which should be available by the time you're reading this. Existing users will be offered a free upgrade. That still leaves colour problems - though most games reset these back to normal if, for example, you leave the room, move to a new screen or get killed. Others can be ugly but are rarely unplayable. Indeed, imaging Ghosts and Goblins cured it of its green-screen visibility problems. Other drawbacks are rather more senous. Imaged games take a long time to load compared to conventional disc-games and eat up disc space like nobody's business. A typical imaged game is the best part of 60K long, and takes something like a minute to load. This is still a worthwhile improvement over the enormous loading times of tape games these days, but it's not exactly all you could hope for. DISCOURAGING PIRACY Some people will also be disappointed to hear that you can only reload imaged games with the Imager present, and that the imager actually encodes its files to keep things that way. To my mind this shows a responsible attitude. Any product of this type is bound to come under attack for encouraging piracy, and the case for legitimate disc-tape transfer needs all the support it can get. Mirage are working on improvements that would mean you could only reload files with the same Imager that was used to save them, and it's good to hear that too. |
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