Miles Gordon Technology - Creating their own Future
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Miles Gordon Technology is a company with a purpose. Bruce Gordon (who created the Gordon Microframe back in the early days of Spectrum computing, and has since designed the DISCiPLE and PLUS D interfaces for the Spectrum), and Alan Miles (who handled marketing at Sinclair Research prior to Amstrads take-over) have a plan to create a new series of microcomputers, the SAM range, giving the computer market a new burst of enthusiasm, as happened when the Spectrum first appeared.
MGTs earlier development of the DISCiPLE interface (giving disk drive, printer, network and joystick interfaces) was in many ways a test bed for the work now being completed on the SAM computer series.
MGTs plan is to develop a computer that can be sold to markets not yet tapped by british manufacturers - India for example. This can only be done by having the computer built in the country - which means that the design must be simple and reliable. This is good news for everyone, as the result will be a cheaper, more successful computer. MGT also wishes to enter the education market, which means that the machine must be cheap (below #150), and have a built-in network. Finally, the machine must be successful, so needs a good software base (hence the use of well known 8-bit technology).
Eventually, MGT hopes that the SAM series will be available to all, in the high street - though at present MGTs successful mail order operation will be used to sell the SAM Coupe. However, MGT do not wish to rush into selling SAM before it is 'right' (remember how badly the Sinclair QL fared because of pre-production selling). In the first month, only 1000 machines will be built and very thoroughly tested (anyone desperate for one of these will need to move fast - over half were already reserved before Christmas). Production will increase slowly at first, to confirm that there are no problems, but MGT are aiming for sales of 56000 SAM machines in the first year (about half in the UK).
The first SAM computer, the SAM Coupe, is now well advanced, and MGT are aiming to release initial production machines to the public in late April. The last few years have been spent finalising the design of one massive chip that will be at the heart of SAM - an 84 pin 'ASIC' (Application Specific Integrated Circuit). This will contain all the circuitry currently developed using around 130 individual ICs. The result for SAM, using this chip (even now being manufactured by Fujitsu), will be a very powerful computer built with just seven chips - Z80B microprocessor, 32K ROM, 256K RAM in two chips, 6 channel stereo sound chip, 64 colour TV modulator chip and the ASIC itself.
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Miles Gordon Technology are creating a new series of Super-8-bit computers, beginning with the SAM Coupe. This machine should be available for under #150, with 256K RAM, 32K ROM, 6 channels of stereo sound and 64 colours available in four screen modes. Users will easily be able to add an additional 256K RAM and one or two disk drives - these are a new ultra-thin design, and will mount in the front of the computer UNDER the keyboard!
SAM will have a 71 key keyboard (with 'soft' key definitions, allowing any key to be a function key, though there are 10 function keys available), a Joystick interface (using the Sinclair standard), a Mouse port, monitor output (as well as a standard modulated TV output), Audio output, MIDI In & Out connectors (the Out can double as a Thru), Printer (serial or parallel will be supported using an 'intelligent cable'), Light pen input and Cassette. There will also be a full expansion connector.
The use of a Z80 may seem odd in these days of Atari & Amiga 68000 designs, but by running it at 6mHz, MGT will get a lot of performance from the SAM Coupe at a lower end cost. In addition, it will be easy for existing software companies to adapt to this new machine - there will be a lot of available software at launch (more on this later).
The ROM is being written by Dr. Andy Wright (the Author of Beta Basic on the Spectrum). Anyone who has used Beta Basic should therefore be assured that the SAM is going to be a 'good machine'. It will still be a Basic computer, but will have letter-by-letter entry (rather than the Spectrum keyword system). There will also be a built-in Disk Operating System, similar to the Plus D DOS, but able to handle random access files.
Sound should be incredible on the SAM Coupe. A 6 channel sound chip will be used, giving stereo output to headphones or hi-fi, and a normal TV signal as well. However, the screen graphics is where the computer will shine. There are 64 colours available, and a Colour Look Up Table allows any of the 64 colours to be selected for the palette. There are four modes available.
Mode 1 is a 'Spectrum' screen - 8 colours with bright and flash, with 8x8 attributes (which will result in the now famous colour clash) on a 256x192 pixel display. However, the 8 colours need not be original Spectrum ones - any of the 64 can be selected. Any since Bright will simply be another colour selection bit, it will be possible to have 16 colours on screen at once.
Mode 2 is a 'Super Spectrum' screen - the same 256x192 pixels with separate attributes, but having a separate attribute byte for each 8x1 pixels on screen - thus 8 times as many different colours can be onscreen at once. This mode also enhances the normal Spectrum display by re-ordering the pixels so that they run sensibly from top to bottom (rather than jumping in thirds as the normal Spectrum does now). Anyone who has tried to write machine code display routines will realise the significance of this.
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Mode 3 is a very colourful screen, offering the same 256x192 pixels - but each pixel can be INDIVIDUALLY set to one of 16 colours, selected from the 64 colour palette. This is the mode that will be used by art programs, etc but since 24K of RAM is needed, it may be too slow for games programs.
Mode 4 is a text screen, offering 512x192 pixels (the same as the ill-fated QL). Each pixel can be one of four colours, but having 512 pixels across the screen allows a readable 80 character display - this is reasonable on a normal colour television, depending on what character & paper colours are selected.
One powerful feature of the screen palette is that it can be altered very quickly. So, using interrupts, it would be possible to change the 16 colours in use by Mode 3 while the screen is being displayed - this would give access to the full 64 colours at once (a similar technique to the Spectrum Rainbow Processor, but rather easier to implement). The SAM Coupe can even change screen modes part-way down the screen - allowing adventure games to have a very hi-res picture of the location, with 80 column text below for the description. It is also possible to change the location of the screen memory by altering a single register (which means that a number of screens can be instantly displayed).
The Memory Paging system is also an innovation (especially when compared with the 128K Spectrums system). The Z80 processor can only access 64K of memory - so even with 32K of ROM and up to 512K of RAM, the Coupe can only use 64K, without special hardware. The SAM Coupe architecture splits the Z80 memory map into four 16K blocks - A (memory addresses $0000...$3FFF), B, C and D ($C000...$FFFF). The ROM is split into 2 halves - one can be brought in over block A (which will hold the Basic code) and one over block D (which will hold the DOS).
There are two 8 bits registers in the hardware, which can be used to select which 16K pages of RAM from the 256K (or 512K on an expanded SAM Coupe) are to be accessible by the Z80. 'Reglo' selects which page is accessible through block A. The hardware AUTOMATICALLY makes the next page available through block B. Similarly, 'Reghi' does the same for blocks C & D.
This may sound complex, but gives two major benefits. The first is that a complete new 64K memory map can be brought in with one machine code instruction, writing to Reglo & Reghi at once (as a 16-bit word). Multi-tasking (of up to four programs at once) would therefore be quite easy and very fast. The second is that it will be possible to write programs that can use the full available memory with ease! If all memory is accessed via blocks C & D using a memory pointer, then any 32K can be accessed at once. When the pointer reaches the top of block D (address $FFFF) a normal paging mechanism would bring in the next page - LOSING the current block D contents. This makes handling information which crosses the boundary very difficult.
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The SAM system, however, makes the problem non-existent. Incrementing the 'Reghi' value will effectively shift the memory in block D down to the block C area, and bring in the next page to block D. Now the pointer can be reduced by 16K (a simple machine code subtraction) and it is then STILL pointing to the same information (though now at address $BFFF). The following page is now available, but so is the previous data.
Another feature of the SAM Coupe is that all the ROM code can be de-selected (giving an all RAM machine - CP/M may appear for this computer as it did for the +3) and memory block A can be write-protected. This allows a new ROM to be loaded in to block A then locked, preventing corruption by rogue programs.
This brings us to the facility of the SAM Coupe to emulate a Spectrum. The screen Mode 1 already gives the same screen format as for the Spectrum. The Coupe also has hardware circuits to emulate the Spectrum beep command. By loading in a tape copy of a Spectrum 48K ROM to memory block A, then write protecting it, the result is a computer which behaves very like a 48K ZX Spectrum, but running faster than normal (with the possibility of choosing a new palette of colours, too).
This feature of the SAM Coupe will mean that many existing Spectrum games can be loaded in & run without problems (the Coupe even emulates the ULA feature used in games like Arkanoid, which was omitted by Amstrad in their +3 and +2A). The Coupe will not, of course, be able to run 128K games - but its more elegant memory addressing and vastly superior sound may mean the death of the 128K Spectrum in favour of MGTs new computer!
Miles Gordon Technology are trying very hard to create a new type of computer market - one in which the customer is considered to be important. The SAM Coupe can take hardware add-ons in much the same way as the Spectrum does (indeed, some Spectrum add-ons can be used with the Coupe) but a proper edge connector will mean the end of RAM pack wobbles! MGT are also making an expansion frame (reminiscent of the Gordon Microframe?) for 'power users'. MGT will also try to control add-on manufacturers so that hardware clashes are avoided - I/O port locations will be allocated to each manufacturer. Some form of snapshot will also be built in to SAM, allowing tape-based users upgrading to disk to transfer their games without hastle.
One other point worth making is that, while we have not yet been told what the rest of the SAM series will consist of, MGT assure us that there WILL be an upgrade path from the Coupe - no more 'throwaway' computers. My suspicion (based on Alan Miles comment that the Coupe is taking 8 bit technology 'as far as it can go') is that a new processor will be used in later models. Perhaps the Coupe will simply be a keyboard, screen and disk interface for some faster processor (much like the old Acorn/BBC tube design).
As the SAM Coupe comes nearer to being on the market, Crash will continue to monitor its progress - it is hoped that a pre-production will be availble by the end of February.
tober '88 for the full review.
The main menu has now lost the COPY command (which has been moved to within the FILES menu, so that all or just selected files can be copied). However, two new commands have appeared - INIT & ANALYSE.
The INIT command (type I from the main menu) allows a disk to be formatted to +3, System or Data format (all three formats are now fully supported by DICE) - the Data format gives an extra 5K per disk, and is a fast format ("DOSROM" saved in 7.6 seconds & loaded in 5.2 - c.f. results for +3 printed in Crash October '88).
The ANALYSE command (type A!) goes some way towards dealing with commercially protected non-standard disks. You can examine, and even modify (at your own risk), disks that normal +3 disk routines cannot read. I would not recommend that you do this on an original disk however - use Kobrahsofts DB1 package first to make a backup!
DICE also now handles CP/M format disks - including decoding disk volume name details, file passwords & user numbers, and date & time stamps.
The sector display now has an additional mode, in which all 512 bytes are displayed at once, in ASCII only - this is very useful when examining/recovering text-only files (or looking through adventure programs, etc).
Finally, there is a new LOG function within the DISK menu. This allows individual sectors to be logged into a list, the contents of which can then be written to a new disk as a complete file. This can, with care, allow a file to be recovered from a corrupted disk EVEN if the directory has been destroyed! It is only really useful for text files, since you must be able to recognise, in order, the parts of the file.
DICE is now 13500 bytes long, leaving 10K free for Basic programs. Its price is still #12.95, and upgrades from version 1 cost #5.95.
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Those of you, like me, using an old 48K/microdrive version of Masterfile, may be interested in a program from Robert Diskson of 12 Coppelia Road, Blackheath, London SE3 9DB. Send him a disk & #2.99 and you will receive a program to transfer Masterfile (including data & report files) from tape to +3 disk. Users of Masterfile on microdrive will first need to save the program & data files to tape. Additional facilities are added via the User Basic function, which calls up a new menu, including CATaloguing, file ERASE & overlay loading. Be warned, however, that very large databases (30K or more approx) will not be usable with Roberts system of saving data on the Ramdrive - though this does allow Masterfile to be RUN without losing any stored data (Yes - there really is a use for the +3 Ramdrive!).
Downgraded +3
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A new and interesting poke has come to my attention, from Kenny Anderson of Dunfermline. Type POKE 23398,4, then FORMAT "A:" - this will result in a +2A error message!
The +2A's are on sale now - they are in Sinclair black (rather than the awful grey), and have an "M:" RAMDISK to which you can SAVE/LOAD all files, unlike older +2's. They do, however, have all the bugs and expansion port incompatibilities of the +3 - in particular, the MGT +D interface (see elsewhere) will not work without a special extra interface, costing #7.95. I suggest that potential 128K purchasers hunt down the grey +2 - there is little to recommend in a +3 without disk drive!
While on the subject of +3 bugs, Kieran Wood has sent in two more curiosities :- When the 'scroll?' message appears, try pressing the EXTEND MODE key, then ENTER. Kieran also warns that entering very long lines (of the order of one screenful) causes unpredictable corruption of the entered line, and/or the complete program - so be careful! There is, of course, no warning issued by the Spectrum of when this will occur.
By the way Kieran, the cursor left bug (printing a cursor left code when the screen is already at top left) will corrupt ALL Spectrums, not just the +3!
CARDEX, or ...
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The company that brought Desk-Top Publishing to the Spectrum (Word Master, Headliner and Typeliner, see Crash September '88) has changed its name from CARDEX to P.C.G. - now at 61 School Street, Barrow-in-Furness, Cumbria LA14 1EW. They have sent me their latest versions, including one for the Spectrum+3, which I will look at in a later Tech Tips - in more detail than Simon managed on his final review!
Next Month
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I will be looking at Art Studio on my Spectrum +3, and hope to find out some details of the Ergo Systems "Clive Drive" ...
Miles Gordon Technology - Creating their own Future
---------------------------------------------------
<<< YOU MAY WANT TO PUT SOMETHING LIKE THIS AT THE >>>
<<< FRONT OF CRASH, RATHER THAN IN TECH TIPS >>>
Miles Gordon Technology is a company with a purpose. Bruce Gordon (who created the Gordon Microframe back in the early days of Spectrum computing, and has since designed the DISCiPLE and PLUS D interfaces for the Spectrum), and Alan Miles (who handled marketing at Sincla