I.S. Plate

Review by Ian Finlayson


Issue 27

May/Jun 87

Next Article >>

<< Prev Article




I have owned an 810 drive for over three years now and it has given reliable service. I remember well the day it arrived and the excitement of its speed after using cassette tapes for some time - a whole new world of practical applications like word processing and accounting became a realistic proposition. Since then, of course, the new 1050 disk drive has come out with enhanced (one and a half times) density, and I have seen advertisements for various add-ons giving true double density and higher speed, but funds are finite and I could never really justify the expense of adding another drive. Recently, however, I do seem to make quite a lot of transfers from one disk to another in an effort to keep my expanding pile of disk files in some sort of order and then, after a recent article was published in Page 6 I swapped several disks with correspondents and two that arrived would not run on my 810 ... formatted in enhanced density! How galling!. I suppose I still cannot fully justify my recent purchase of a 1050 drive and the IS PLATE to fit in it, but I certainly have no regrets and I am happy to tell you more about it.


I am very fortunate living near Worthing as we have an excellent, helpful, computer shop here - Chips - and it specialises in Atari computers and software. I recently saw an advertisement of theirs extolling the IS PLATE which interested me as it sounded a bit like the US Doubler, or Happy enhancement, but I had not heard of it before, even in the American Atari magazines, and nobody else was advertising it. So I dropped in at Chips to ask about it. It turned out that the Plate is a local product invented and developed here in Worthing. This device is British and follows up the recent expansion of good British software for the Atari in hardware terms, however, I wondered if it would be a useful addition to my computer system. With a price near a hundred pounds it is quite expensive compared to the cost of the disk drive itself or to the cost of a 130XE for that matter. Before my doubts could subdue my enthusiasm I was being given a demonstration combined with a good bit of informed salesmanship. My first impression of the machine was of speed and quietness and I was captivated.


The Plate itself is a small printed circuit board with five chips on it; these include a 6502 chip, 16K RAM and an EPROM. The device appears well engineered and professional with clean soldering. Installation is very straightforward and anyone who can change a mains plug should be able to tackle this with confidence. The instructions are clear and are supported by Xerox copies of photographs of the assembly process which, though not very clear, do give an adequate indication of what to expect. If you read and follow the instructions carefully (including the precautions against static) and don't rush you will have no trouble - it took me well under 10 minutes from start to finish. The new PCB replaces the ROM and CPU chips in the disk drive board and plugs into the CPU socket - no soldering! There is a small cut out in the PCB which fits over a crystal on the main board so you can not even put the new board in the wrong way round.


The IS Plate is accompanied by a disk of software for use with the device. On one side is the ISP driver while on side two is the IS Menu.

The ISP driver is a menu driven set of programs which are principally concerned with setting up the drive for your requirements. You can select Skew, Fast Write, Verify, Slow down and Write protect and these functions remain enabled until the drive is switched off. There are also two high speed copiers on the disk, one for 130XE and the other a general purpose copier. They are fast but will not copy protected disks.

You can also select to emulate the IS Doubler or a standard 1050 drive. This means that you can make the Plate invisible to commercial software that will not run on an enhanced drive.

The IS Menu (or Lighter Menu) is rather like Multiboot XL allowing several boot programs to be menu driven off one disk. It is colourful, has sound and a special character set and is based around a special DOS which only works with the Plate and gives a very fast load, something over twice the speed of Multiboot XL. Also on the menu is the IS Customiser - this is a utility which allows you to create your own custom disk formats with mixtures of different densities, bad sectors, duplicated sectors and extra sectors. If you are a skilled programer this means that you can protect your great works but a good knowledge of disk drives and operating systems is necessary if you are to make full use of this facility.


I can not go into detail of all the attributes of the Plate here so it is fortunate that the 26 page user manual is quite comprehensive. To begin with you will need to refer to it frequently and you will need further reference books to get the most out of this very versatile drive unless you already have a good knowledge of disk systems. The handbook introduces some of the more technical details needed to start programming the drive yourself, but such a task is certainly not for the beginner!

One very useful feature of the drive is not mentioned in the manual - the drive can be switched to standard 1050 emulation by switching on with write protect enabled (either by a write protected disk or an unprotected disk partially inserted). ISP is enabled by switching on with the drive empty or an unprotected disk installed.


In summary the main features of the ISP are:

Provides an intelligent disk controller and buffer.

Reads a track at a time from disk, speeding access and reducing drive wear.

Gives single, dual and true double density (with suitable DOS).
Fast read and write.
Archiver and ISD emulation (with appropriate software).
Standard 1050 emulation makes Plate invisible to commercial software.


Having discovered that this device was designed and built locally I thought it would be interesting to meet the brains behind the product and coincidentally met Robert Perry in Chips and he kindly agreed to talk to me about his product. Robert has had an Atari from the very early days (about 1980) when he started with a 400 with 16K RAM and a cassette recorder at a cost of several hundred pounds! He clearly knows the anatomy of his Atari and disk drive inside out and has previously developed the IS Doubler which sold in small numbers, mostly locally, but was never advertised. He has been working on the Plate since about Easter of last year and showed me the prototype board on which the device was assembled and tested before the neat PCB design was developed and the boards made. Although he gets the PCBs made the rest of the work is his own, and a very professional job he makes of it. He is beginning to develop ideas for a sound sampler which will use the speed and power of the ST and a video flash digitiser or frame grabber which will digitise a frame of video transmission, possibly with video mixing, allowing computer generated graphics and computer manipulation of the frames for special video effects.

As well as informing me about his product, Robert tried to tell me more about disk formats, sector skew, disk protection techniques and so on, and I understood some of it. If you are knowledgeable in these areas then you will surely make good use of the plate. One factor that will be of interest to all Plate users is that the modification does not give much of a speed enhancement when used with an ordinary DOS such as DOS 2.5 but will read in a program on a disk formatted under SpartaDos just about twice as fast because the SpartaDos format matches the capabilities of the Plate.

If any of you develop software specially for this device I am certain Robert would like to hear from you. With the memory and intelligence that is built in there must be considerable potential ... could the Plate serve as a printer buffer for instance?

This is an excellent, innovative, well engineered product and I wish Robert every success in achieving a wide market.