Microtan 65 Review

Microtan_65_001

Just another 6502 system? We think not. Microtan’s expandability is almost second to none and it could be a winner.

By Henry Budgett

The ideal system in most people’s minds is one that is as cheap as possible, provides the most facilities, is expandable to the limits of its design and can be obtained piece by piece as the money is saved. Up to now there have been several systems that have sought to achieve these varied aims, and the results have been many and varied.

The machine reviewed here is another contender in this field and certainly seems to be set for success where others have not. Based on the 6502 CPU, the same chip as used in PET and Apple among others, it has several very interesting items to offer.

Concept of A System

The usefulness of a computer on a board is limited, the usefulness of a system with attendant peripherals is much greater. The ideal balance is struck when the single board can become part of a system and thus have the capability of fulfilling the needs of both markets.

Microtan has been designed in this way, the complete system has been planned and is then offered board by board. This review is only going to cover the basic board but mention will be made of the available expansion to construct the system. Table 1 gives details of the various stages that are available, in their various configured forms.

Assembly Or Assembled?

I built the Microtan from a kit, something that I believe is worth doing as you not only save money but you do get an insight into how the hardware is strung together.

Presentation is superb and to anyone who is competent with a soldering iron this should represent no more than an evening’s work. Please note that the PCB is double sided and through-hole-plated so you must use a fine tip on the iron and fine solder otherwise you will have problems.

The manual that is supplied covers all the areas needed to construct the kit and get it up and running. It covers other areas that I will mention later. The only serious omission is the lack of a circuit diagram, but this is being rectified I gather. You will need a power supply, the 5 volt supply that we published in CT serves admirably or you can buy one from Tangerine.

The true test of any kit is whether it works, it did in its basic format and with the graphics option in place but it died when I tried to add the lower case option. Immediate thoughts of dead ROMs were not correct, the eventual culprit was a tri-state device that was permanently tri-stated. Quick work by Tangerine meant that I was back on the screen before the postman had called twice.

Micro Monitor

The old question of “How much can you fit into a pint pot?” rears its ugly head with Tanbug, the 1K monitor supplied as standard. The answer in this case is “Enough!”. At this stage you have a system that can only deal with machine code and a glance at Table 2 will show that there is only one possible omission from the monitor, that of cassette handling. Well, you don’t have a cassette interface yet so what are you worrying about? If you are going to expand to Tanex, which has that necessary interface, you get the routine for handling named files which you can either load up yourself or get in an EPROM that plugs in to a socket and is called through Tanbug. The cassette handling is at a choice of 300 or 4800 Baud so you can’t even boil the kettle let alone drink a cup of coffee while loading programs.

What does Tanbug have that sets it apart from other monitors? Two things really, you get a full listing of the firmware with notes and explanations and you don’t get any bugs, at least I haven’t found any yet. It does all that the Microtan user will require and if you ever get big enough to warrant it there is a bigger version called XBUG lurking in a dark corner.

Manual Means Handy?

The little orange covered book that is supplied is worthy of a mention in its own right. OK, it’s not perfect but it is detailed and concise. One or two errors have escaped correction but nothing that will cause the crashing of programs or other damage. The book fits into a ring binder and will be joined by the manuals for Tanex and the other family members, a neat concept in its own way.

For a change the manual is logical, it explains the concept of the board, then the system, then the details of the 6502 with the complete instruction set and then a very detailed chapter on the monitor and its uses – complete with the listing and finally it gives you a couple of games. It is essential to read the whole thing through from cover to cover before starting to play, the unit is complex and should be understood before anything is attempted.

What You Get

Once the board is built and the manual read you are ready to go. All you need now is a black and white TV and a 5 volt power supply at about 1 amp. Connect up, turn on and hit reset. The screen is covered in a pretty pattern with the words TANBUG at the bottom followed by a prompt character. At this point we find the only serious problem with the system. You have a ? on the screen but you are told that you should have a square blob, have you blown it up? No, you haven’t got the lower case option. It is explained in the manual but it is very unclear and has caused much confusion and alarm both in the office and outside.

So, you have a working system. Machine code programmers can now go and have a ball, the rest of us start learning. If you are a dedicated BASIC person Tanex is a must, throw away the Hex keypad (superb thought it is), plug in the full ASCII, the system works out which you are using, and let yourself go with a 10K Microsoft BASIC.

Points worth of note, and praise, are the rock steady display on your TV, the VDU RAM is only accessed when the system RAM is not so you don’t get the usual flicker, the excellent Hex keypad and the almost unbelievable packing density. Because the system is based around the 6502 comparisons with the Acorn, reviewed in August 79, are almost inevitable. With Microtan you get a proper VDU as opposed to an LED display, a decent keypad that is separate and a slightly more powerful monitor but you do lose the cassette (at this stage).

The Guts Of The Matter

Figure_001

Fig.1. Microtan’s architecture, all on one board to!

Because of a lack of space on the board certain apparently ignored features are implemented at other points in the system. Figure 1 shows the architecture of the board, the keyboard interface is intelligent in that it detects what type is being used. The memory map of the system, see Fig.2, appears to be rather limited, full decoding is done on the Tanex board and gives the map shown in Figure 3. This is not the disadvantage that it might appear to be, it allows the contents of RAM on Microtan to be protected against DMA as are the I/O ports and the ROM area. Whilst on the subject of I/O it is worth noting that you get a 1K area that is addressable as I/O, this compares with a maximum of 256 on devices using the Z80 or 8080.

Figure_002

Fig.2. The simple memory map produced by Microtan

Figure_003

Fig.3. Once you’ve added Tanex you get a proper memory map, which is fairly impressive.

The system expansion is shown in Figure 4, full details of the bus structure are given along with notes for DIY people. The address bus buffer chips are supplied as part of the Tanex unit, so don’t worry about the empty sockets.

Figure_004

Fig.4. How you expand through Tanbus

On Board Options

Despite the fact that the basic Microtan packs in a 6502, keyboard interface, VDU, 1K of RAM and 1K of monitor ROM there is more to come! As seen from the previously mentioned Fig.4 the address bus buffers fit on, but that’s not the end. You can have lower case alphabetics, not essential at this stage, and pixel type graphics, sometimes called “high resolution” but really made up of little squares not dots. Tangerine are quite honest about them and call them “Chunky” which is a very apt description, they are good enough for Teletext simulations and games etc.

Because of the ingenious VDU design it is quite possible to run a program that actually resides in the screen memory without bombing everything, try that on your system.

Expanding Horizons

Glancing back to Table 1 you can see the basis of your system emerging. The rest is coming shortly and completes the story. Tanram will be the next board to go on sale and offers 40K of memory on a single board and this will have the capability of bank selection so RAM freaks can have the odd megabyte or six if they want. You may have realised that the system is now full, see Fig.3. Next on the stocks is Tandisc, offering you the floppies that you dream of, up to four double density units are planned.

Microtan_65_004

The Microtan board installed in the mini-rack

Microtan_65_003

Tanex fits on top in the mini-rack system, along with the power supply and Hex keyboard.

Housing all this exotic hardware need not be a problem either, the case that Tangerine supply will hold Microtan and Tanex complete with power supply. The other style that you could use is a card frame, I am building my system in a Vero unit, assembled from System KM4C parts which also offer such goodies as front panels and modules. However you could design your system to fit into a VDU case and have a self-contained system, it’s up to you.

Microtan_65_002

The author’s system growing inside a Vero rack.

Summing Up

Microtan, and its attendant extras, offer the first time buyer a low cost entry point into computing. Taking a boxed two-board system with all the options, power supply and key board you have a more powerful unit than a PET, it has more I/O capability and at £350 it is a lot cheaper!

The product appears to have been launched with a great deal of thought and planning, in itself a change from some rivals, and seems to have found a niche in the market almost overnight. The only thing it hasn’t got is a “second generation” CPU such as a Z80 or 6809 but that doesn’t seem to be too much of a handicap, the dedicated machine code programmers among you might disagree but no-one else has!

Table 1. The various system configurations for Microtan
Board Microtan 65
Features 6502, 1K RAM, 1K ROM, 6 I/O ports
Options Pixel graphics, lower case alphas, address bus buffers
Need to run TV, Hex keypad, 5V PSU @ 1A

 

Board Tanex
Features 1K RAM, 16 parallel I/O, TTL serial I/O, cassette I/O, 2 by 16 bit counter timers, full memory map, data bus buffers
Options 6K RAM, 4K ROM, 10K Microsoft BASIC, double above I/O plus RS232/20 mA serial with full modem control

 

Board Tanram
Features 40K mixed static and dynamic RAM

 

Board Tandisc
Features Control of four drives
Extras Motherboard, case, power supply, Hex keypad, ASCII keyboard

 

Table. 2 The available monitor commands on Tanbug
Monitor Command Function
M(add)(term) Modify memory locations, terminator type allows step through, cancel or jump out.
L(add),(numb)(term) Lists the contents of specified memory locations in tabular form.
G(add)(term) Sets internal registers and executes program at address given. NB cursor disappears.
R Sets memory modify command to register mode. Allows the 6502s internal registers to be altered.
S Sets single step mode, see P & N
N Resets to normal mode from single step
P Causes monitor to execute next instruction, can be set to execute n instructions. Gives display of all registers and returns to monitor.
B(add),(numb)(term) Sets breakpoint at specified address, up to eight are allowed. All registers are displayed and P command may be sued to continue.
O(branch add)(dest add)(term) Calculates offsets between specified addresses for use in branch arguments.
C(start add)(end add)(start add dest)(term) NB (term) can be CR, LF or SP Copies memory locations and blocks.

 First published in Computing Today magazine, June 1980

Advertisements

Samson Reviewed

Samson-1_001

Underneath a new exterior the Samson reveals itself as an original ‘Mighty Micro’.

By John Fitzgerald

When the Editor slipped me a Samson-1 with a request to review it, I wondered what I was getting. It was a pleasant surprise to discover that the Samson is just a Sym-1 in a smart plastic case. I had played with a Sym for a few days some months before and was pleased to get my hands on one again. If you are thinking of spending your hard-earned cash on one of these space-age toys, you need to know one thing. Is it any good? I am happy to report that the Samson is good – very good.

The Samson-1

For the technically minded, a functional block diagram of the system (Fig.1) shows the major hardware features of the Samson and indicates some of the many expansion options available. The computer is housed in a two-piece plastic case. The upper section is pivoted on two plastic studs making it “click-fit” and thus easily removable. A clear plastic cover may be slid down to cover the keyboard and display. I found it easier to remove the lid completely as even with the cover slid out of the way, access to the keyboard is severely limited; requiring an awkward vertical stabbing motion.

Figure001

Fig.1 System architecture of the Samson/Sym. Enough to satisfy most single boarders.

The Samson is supplied fully assembled with two comprehensive manuals and a programmer’s reference card included. The only extras required are a 5V 1.5A power supply, suitably protected against overload, and a cassette recorder for low-cost program and data storage.

A high quality, double sided printed circuit board holds all the components including a 28 key ‘spongy-plastic’ keypad and a 6 digit 7 segment display. Also included is a piezo-electric ‘bleeper’ similar to those used in digital alarm watches. This gives an audible response each time a key is pressed making use of the keyboard a much more certain operation. Of course, it is all under software control and yes, you can play tunes on it! The ‘debug’ function is achieved with a hardware connection and this key does not give an audible response. However, the reference manual includes details for connecting a LED indicator which would easily remedy this omission. Though designated on the functional block diagram as a ‘Hex’ display, the on-board LED display consists of six standard seven-segment units resulting in the usual ‘abbreviated’ representation of the alphanumeric character set. The red display is nonetheless quite bright and easy to read. Use of a small piece of Polaroid would make it even better. A red plastic filter was included with our unit.

Sockets are provided for the MOS integrated circuits. Make sure the chips are fully inserted before applying power. A nice feature is the provision of blank sockets on the board enabling the memory to be expanded up to 4K and extra input-output to be fitted by simply plugging extra chips into the appropriate sockets. Extra RAM and a port expansion and connector kit are available as part of the Samson system. The overall layout of the printed circuit board is clean and uncluttered and component and connector positions are clearly marked on the component side in white ink.

Figure002

Fig.2 The Sym/Samson keyboard layout.

The documentation supplied with the Samson deserves a special mention. As well as a reference card containing op-codes, system addresses, etc, two manuals are supplied. One features all the information that you will ever need to know about the processor’s instruction set while the other contains essential data for the hardware orientated enthusiast as well as complete data sheets on the major LSI chips. Both are produced on good quality white paper with a wealth of diagrams and useful hints. These are the kind of books that cost you a fiver each in the shops and they come as standard issue with the Samson computer.

Chips

The heart of the system is a 6502 microprocessor running at a 1MHz clock frequency. This will be familiar to computer buffs as the 6800 derived powerhouse used in the KIM, PET, Apple, Acorn and Tangerine systems. (I wonder why hard-headed manufacturers choose such fruity names!) There are two 6522 Versatile Interface Adaptors in the basic system which handle input-output. These also contain software programmable timers which can be configured in numerous ways. In short, as their name suggests, they are versatile – very! Provision is made on board for insertion of a third 6522 if you can think of a use for it that is not already provided for. The board fairly bristles with connectors. These are high quality double sided, gold plated pads and mating sockets are provided either with the basic unit or are available as part of an expansion kit. Also present is a 6532, RAM, I/O, timer array which offers many features comparable to those offered by the 6522. What makes the 6532 special is the inclusion on-chip of 128 bytes of random access memory. This is software write-protectable and is used by the monitor to store system vectors and as scratchpad memory.

Memory

As well as the RAM contained in the 6532, 1K of RAM is provided in the basic system in the form of two 2114 (1024 x 4) chips. One 4K ROM chip holds the ‘Supermon’ monitor and there are spare sockets for an 8K BASIC interpreter and a resident assembler-editor. Pairs of 2114 chips are available as the ‘Samson Static RAM memory’ enabling expansion of the on-board RAM in 1K blocks up to 4K.

Monitor

The ‘Supermon’ monitor is the largest I have come across in a single board computer… and it does not stop there. Expansion is possible through the use of eight undefined keys (USR 0 thru’ USR7). These normally return control to the monitor via a vector address written into system RAM. By changing this address to point to a user written routine you can expand the facilities offered by the monitor in any desired way. Excellent and extensive hardware is provided on the Samson board and this is well used by the monitor which supports the following input-output and storage media:-

  • TTY – selectable current loop
  • VDU – RS232 interface. Baud rate is automatically determined by the monitor at log on.
  • Paper tape – data is stored as pairs of ASCII characters.
  • Audio cassette – two formats are available. The low speed system is KIM compatible and operates at 8 bytes/sec. A high speed mode is also provided and runs at 185 bytes/sec. A simple program is included in the reference manual enabling the generation and use of SYNC tapes facilitating adjustment of the cassette recorder. One with both volume and tone controls is recommended.
  • Oscilloscope display – this enables a single line of text containing up to 32 characters to be displayed on a conventional ’scope which is all you need to supply. A suitable software driver is included in the reference manual and instructions are given for generating your own character set.

The extensive use of command vectors enables the Samson owner to direct input-output to any chosen device(s). Some examples of how to do this are given in the manual which also contains a complete and legible listing of the monitor. This facilitates the use of monitor routines in your own programs and is an aid to anyone learning to use machine code. Table 1 shows the monitor commands and their function.

KIM Compatibility

The Samson is designed to be generally upwards compatible with MOS-Technology’s single board KIM computer. In practice this means that some of the connectors are different; for example, the Samson uses a separate connector for the power supply, and some of the signals are absent or renamed. Though both machines use the same microprocessor, the 6502, they are not directly software compatible. Inconsistencies include timer addresses and a number of monitor routines. Those most likely to concern the prospective user are the keyboard and monitor sections which feature most strongly in pre-written KIM software; for example, in the ‘First Book of KIM’. It is possible to use programs from this source. However, you will have to provide some software links to the Samson system. These are best provided in the form of subroutines which can be called when required. Here’s a tip. Remember that you must call ‘ACCESS’ before you can even begin to think of getting at the LED display.

BASIC

For anyone who turns white and shivers at the first mention of machine code, those nice people at Samson (Synertek – why pretend?) have come up with an 8K BASIC Interpreter. Supplied in the form of two 4K ROMs, it only requires plugging in to the sockets provided and a couple of wire jumper changes to be up and running.

With BASIC installed, following power-on, a TTY is logged on from the Hex keyboard or a VDU is logged on by typing ‘Q’. The monitor responds with a prompt Now if J 0 (CR) is entered, BASIC responds by asking for the memory size to be used. Any value greater than 512 bytes may be entered. BASIC will use all contiguous memory from location 0200 (Hex) to the value specified. This enables space to be reserved for machine code routines. You will then be asked to specify terminal width which determines the output line width for PRINT statements only. There is a default value of 72 characters though any value between 1 and 255 may be used. BASIC will then type out the number of free bytes, Synertek’s banner and ‘OK’. The prompt character (.) is replaced by a flashing cursor if you are using the Samson terminal.

There is no space here for a full description of the BASIC. It seems to have everything you would expect from an 8K interpreter and includes commands enabling you to use machine code routines in your programs. A sixty-page manual contains a brief history of BASIC with notes on its implementation in the Samson system and some worked examples and details of common pitfalls. There is certainly nothing wrong with the BASIC provided and it is good to see it offered as part of what looks at first glance like a simple development kit. However, I cannot help feeling that, if you want to talk BASIC, you should just go out; buy a PET, put the Programmer’s Toolkit on it and talk to that. PET speak heap good BASIC!… and the screen editing and graphics capabilities are excellent for a black and white system. The Samson is a superb piece of hardware with excellent software support and it seems foolish to ignore all that just to talk pidgin English!

Samson In Orbit

The Samson Satellite consists of yet another Synertek product, the KTM-2, in another plastic case. This is a full-size keyboard mounted on a single PCB which also contains circuitry to drive a display monitor. There are two models differing primarily in the number of displayed characters per line. The 40 character version may be used with an ordinary television while the 80 character unit requires a video monitor. An RF modulator is not supplied with either unit and must be purchased separately. Power requirements are simply 5V at about 1 amp.

Samson-1_003

A typical screen dump showing the squashed display. The Hex pair on the right is the checksum.

The keyboard consists of 54 keys which enable the full ASCII set and 128 graphics characters to be generated. Graphics and alpha-numerics may be displayed simultaneously and the cursor may be software driven using absolute or relative addressing. There are two full-duplex serial communication ports enabling the Satellite to interface to a computer and printer simultaneously. Transmission rate is adjustable between 110 and 9600 baud. There are eight ranges selected by three switches. Other switch selectable functions include:

  • even, odd or no parity
  • interlaced or non-interlaced display (an interlaced display may appear to flicker on a screen with a short persistence phosphor.)
  • line truncate or wraparound
  • choice of 50Hz or 60Hz frame rate.

Almost everything in the Satellite responds to automatic control. The cursor may be moved, screen cleared, graphics selected or deselected and reverse video turned on or off: all under software control. You enable the auxiliary communications port with an ASCII control code too!

Samson-1_004

How characters are made up on an oscilloscope display.

Samson-1_005

What you get when you jump to BASIC.

As you will see from our photos, the Satellite’s character rows are very close. This was done primarily for the graphics characters to connect in a vertical direction but does result in a rather cramped display with an awkward aspect ratio. One or two extra scan lines may be added by re-configuring some jumpers on the PCB. Full details are given in the 40 page A4 size manual which includes all the technical data required and adds some hints for users operating Synertek BASIC.

Figure003

Fig. 3. The graphics set of the Satellite terminal.

The Satellite is a well produced unit offering many sophisticated features and makes a good companion to the Samson-1. In conclusion, the Synertek BASIC and Satellite terminal are good. The Samson (Sym-1) is very good indeed and deserves to find wide acceptance in this country. If this article has whetted your appetite, all you have to do now is come up with the cash, go out and get one!

Table 1. The Supermon command set.
Command Function
M Display-modify memory
R Display-modify user registers
G Restore user registers, resume execution from PC
V Display 8 bytes of data with their checksum
D Deposit data from keyboard to memory
C Calculate using Hex arithmetic, displacements etc.
B Block move in memory
Jump (0-7) loads PC with address from system RAM
SD Stores a double byte
F Fills block of memory with chosen byte
W Write protect user RAM in 1K blocks
E Adjusts monitor to receive input from RAM
51 Save cassette tape KIM format
52 Save cassette tape high-speed
L1 Load KIM format tape
L2 Load high-speed tape
SP Save paper tape
LP Load paper tape
CR Carriage return
+ Advance 8 bytes
Retreat 8 bytes also used as delimiter
> Advance one byte or register
< Retreat one byte
USR0-7 User defined keys
SHIFT Select upper case
RST Reset
DEBUG Hardware debug function
ON-OFF  
ASCII Next two keystrokes combined to form one ASCII character.

 

Program to make the bleeper bleep, alter value at 011C to change note pitch
  100 20 88 81 JSR SAVER
  103 A9 0D   LDA 0D
  105 20 A5 89 JSR CONFIG
LOOP 108 A9 08   LDA 8
  10A 8D 02 A4 STA PBDA
  10D 20 1B 01 JSR
  110 A9 06   LDA 6
  112 8D 02 A4 STA PBDA
  115 20 1B 01 JMP LOOP
  11B A0 50   LDY 50
  11D 88     DEY
  11E DO FD   BNE FD
  120 60     RTS

First published in Computing Today, June 1980

Commodore 64

C64_Main_001

The 64’s strong selling point is its memory capacity, but – as Simon Beesley discovers – its other features all conspire to make it something of a force to be reckoned with.

The Vic-20’s stock has fallen slightly since it first went on sale last autumn. At the time it was welcomed as the only computer under £200 with colour and sound. Now it seems overshadowed by a number of competitors which offer more features at an equivalent price.

People tend to point to the Vic’s limited memory capacity – only 3.5K – or its constricted screen layout of 22 columns by 23 rows, and belittle its strong characteristics as secondary features. But such secondary features as well-spaced and robust keys, or a good screen editor assume great importance for anyone who spends much time programming.

Improved screen size

The Commodore 64 remedies most of the Vic’s shortcomings, while maintaining its virtues. The keyboard layout is the same and, apart from its beige colour, the casing has the same size and appearance. An extra games socket supplements the number of ports available on the Vic. These allow attachments to cassette, disc drive, program and games cartridges. A user port which will take a Z-80 cartridge to give the 64 access to CP/M software is also included. The VicModem, RS-232 and IEEE interface cartridges can also be plugged in.

Memory capacity and screen size are two areas in which the Commodore 64 improves on the Vic. 64K RAM is on board, of which 38K is available for Basic programs. The screen format gives 25 rows of 40 characters. Like the Vic, there is a choice of 16 colours and two character sets which include predefined graphic characters.

Commodore micros score highly for the ease with which one can change character sets, select graphic characters and alter the text or graphic colour. All this can be done through a combination of control and colour or graphic keys. Compare this with the laborious business of keying in a VDU command on the BBC Micro to change colour.

Easy to set up displays

Setting the background and border colours is equally convenient and just requires Poking a value into a single memory location. Multicolour mode on the Vic and the 64 enables you to use four colours within a single character space but is really only suitable for user-defined characters. Extended Colour Mode on the 64 is a new and more useful feature, which allows you to choose one of four colours for the background to a single character. The drawback is that only the first 64 characters can be used in this mode.

The 64 runs the same Basic as the Vic, itself more or less the same as Pet Basic. Programs should be transferable from other machines with 40-column displays if Peek and Poke addresses are changed.

The attractive feature of this Basic is the convenient way that cursor and colour control characters can be entered into character strings in a Print statement. They determine the screen position and also the colour of the text or graphics that follow after – making the task of setting up the display in a program considerably easier than it is in other versions of the language.

In these and other respects the Commodore incorporates almost all the specifications of the Vic-20. But it would have to be more than just an expanded Vic to justify a price of nearly £350 including VAT. Sprite graphics and a powerful sound generator are the features which supply the difference and lift it into the BBC Micro class.

The sound facility is at least as extensive as the BBC Micro’s and, arguably, easier to use. Rather than being embedded in sound and envelope commands, sound control is obtained by Poking values into specific memory locations. The 22 sound-memory locations allow you to define notes in up to three voices with a range of eight octaves. Each voice can be set to one of four wave-forms – triangle, sawtooth, pulse or noise. The attack and decay and sustain/release parameters affect the way the volume of a note develops and fades.

Like the BBC’s generator, the sound facility approaches that of a full sound synthesiser. A fairly close simulation of instruments such as the piano and harpsichord can be achieved as well as a variety of sound effects – the sound of jet engines, gunshots, wind, surf, snare drums, cymbals are some of the possibilities mentioned in the provisional manuals.

Sprites are user-definable shapes which can be moved around a 320 by 200 dot screen. The term was coined by Atari which offers a similar feature on its microcomputers. A sprite object is defined on a grid 24 dots wide and 21 dots long; up to eight of them can be controlled at a time.

Fun with sprites

The video-display chip handles the writing and deleting of the shape on the screen. All the user needs to do to move a sprite is Poke new X and Y co-ordinates into the sprite register.

It is also possible to expand sprites, change their colour, and make them pass behind or in front of other objects on the screen. Two locations in the register can be read to detect potential collisions between sprites or other background objects. Clearly sprite graphics will be useful for games applications, particularly since they can be displayed on the ordinary screen with many other text and graphic characters, as well as in the high-resolution mode. It is not difficult, for example, to program a flock of sprites to pass behind the lines of a program listing – a rather bizarre sight.

The ability to read the entire character generator from ROM into RAM is a boon to the Vic user which makes up for some of the machine’s deficiencies and provides a limited high-resolution facility. Not only does the 64 share this flexibility, but it also supplies a separate high-resolution mode. You can open a screen with a resolution of 320 by 200, which is bit-mapped to an 8K screen and leaves 24K RAM available to the user.

But it is a little misleading of Commodore to claim that the standard 64 offers high-resolution graphics since the Basic does not contain any line or point-plotting commands. Poking to screen memory would indeed light up a pixel; but locating a single dot on the screen is complicated by the fact that the bits in memory correspond to eight by eight blocks rather than successive rows of dots.

Promise for the future

A true high-resolution plotting facility on this machine will have to wait for the arrival of a language, which supplies commands like Plot, Circle, and Paint. Such a language is Simons Basic, which will furnish the resident Basic with refinements such as If-Then-Else, definable procedures and error-trapping found in more advanced Basics. This development will enable full use of the 64’s ample memory capacity – 38K user RAM. One of the eight other possible memory configurations releases 52K for machine code or other languages.

Conclusions

  • The addition of sprite graphics, high-resolution mode and a very effective sound generator to the Vic’s specification make the 64 a very different, far more powerful and versatile machine.
  • Like the Vic, the 64 will profit from a large range of cartridge-based software – as much of it for business applications as for games.
  • It will be able to take advantage of much of the software and accessories for the Pet and the Vic, while cartridges for the Max – also known as the Vic-10 – are compatible with the 64.
  • The 64 is let down by a rather limited Basic. The forthcoming Simons Basic should make good this failing, although it will up the price by at least £50.
  • In respect of its other features the 64 is an excellent machine which can be highly recommended.

First published in Your Computer magazine, October 1982

Review MPF-II

MPFII_Main001

Tim Langdell discovers whether the 64K MPF-II really is an Apple at far less than half the price.

Taiwenese Multitech has pushed a new contender into the £200 colour-computer arena. Its MPF-II is a 64K 6502-based machine with six colours and a Basic which bears far more than just a passing resemblance to Applesoft. In fact the MPF-II is almost identical to a 64K Apple II – but without the expansion potential – and will run most Apple software.

About 32K of RAM is available to the user, and a further 16K or so is required for the video pages. It uses 16K of ROM, which again seems very similar to the Apple II. Indeed the few Calls we made to the ROM produced the same results as on our Apple. For instance, Call -932 cleared the screen, and Poking location 33 enabled us to set the line length to any given value.

Positive keyboard

The MPF-IIs unattractive casing is flat and light-grey, about 7in. wide by l0in. deep, by about 1in. high – it is rather like an Apple in a Spectrum case. The keyboard is of the calculator type, although it has a more positive feel than many on the market. Multitech claims an inexpensive add-on typewriter-quality keyboard is also about to be released.

As soon as you begin to work with the MPF-II its similarity to the Apple becomes apparent. There are three modes: text, low and high-resolution graphics. The text mode is black and white only, but six colours are available in either of the graphics modes. The lower-definition graphics mode has a resolution of 40 by 40, while the higher is 280 by 192. The MA command moves the screen memory to another location, and there is a choice of two high-resolution screens. The first leaves four text lines at the bottom of the screen: the second leaves just one line for, say, error reports.

The MPF-II has a full QWERTY keyboard with larger keys for Return, Space, Control and Shift. There is also a reset button, which is set precariously close to the 0 key, and four cursor keys. The keyboard is uncluttered, but hides many secrets.

Use of templates

The first of the two templates supplied with the machine reveals that the keys provide a full range of graphics functions, accessed by pressing CTRL B followed by any key. There are a total of 49 graphics ranging from a variety of line-drawing aids, through block graphics, to hearts, clubs, diamonds and spades.

The second template presents the surprise; pressing Shift and CTRL at the same time – they are conveniently adjacent – along with another key produces a full key-word on the screen. Thus you can type words in the normal manner, as well as use the Sinclair approach of single-key entry. Offering both is an excellent idea, and using templates instead of cluttering the keyboard is ingenious.

At the back of the MPF-II are sockets to attach either a domestic television or a video monitor. There are also Mic and Line sockets for your cassette recorder, and one for an AC plug. On the left-hand side is a printer interface, a plug-in ROM socket and a labelled RCB.

This socket is for the £10 Remote Control Box – or either a Chinese-character generator, an additional keyboard, or an £80 speech synthesis and sound-generation box.

The MPF-IPs Basic is excellent and, as stated, virtually identical to Applesoft. It may well represent the most powerful Basic available with a machine which costs less than £200. Table 1 gives a list of the key-words.

Capacity for graphics

Although the MPF-II can use only six colours, it can plot them in even the highest resolution. This is in contrast to all the other sub-£200 computers on the market which either limit the number of colours available in the high-resolution mode to two, or only allow definition of colour by character squares – for example, the Spectrum.

The MPF-II is thus capable of very good colour graphics in a limited range of colours. This is enhanced by an excellent facility again, as offered on Apples – to be able to draw shape tables in memory using Draw, XDraw, Rot, Scale and SHLoad.

With these commands you can display a defined shape in memory on the screen, either as it was written into memory, or scaled up or down, or rotated through a given number of degrees, or drawn in the complement colour – XDraw. In addition it is possible to load such shapes onto cassette or disc and recall them again astounding abilities for such an inexpensive computer.

The Basic contains all the standard data and variable handling key-words along with such unusual but very useful commands as OnErr Goto – when an error occurs a Goto is executed – On Goto, and On Gosub. The two graphics resolutions are set by either GR for low resolution or HGR for high.

Drawing lines and plotting points are easily produced with commands such as Plot, VLin, HLin – drawing horizontal and vertical lines  – and Scrn which returns the colour code of the point defined. The printer can be switched on or off using PrtOn and PrtOff – and one presumes that these two replace the more extensive Prt# commands on the more expandable Apple II.

The ability to delete blocks of lines from programs using Del is welcome, but the Basic sadly lacks a renumber routine. Screen editing, Multitech claims, is possible by moving the cursor to the line on screen with an error and retyping it. However this full screen-editing facility did not seem to work on the review version.

A rather interesting plus for those used to other inexpensive microcomputers is the fact that like the Apple the MPF-II has a built-in monitor which can be Called from Basic. Once Called, memory locations and register situations are displayed. With simple one-key commands you can disassemble any area of the memory map into 6502 mnemonics.

Hex dumps are also possible, and there is also a facility for testing areas of RAM for certain bytes, moving bytes in blocks to other locations, and reading and writing machine code to tape or disc. Multitech has included two such systems, one for its own system, and one compatible with the Apple II.

Although sound is clearly possible with the MPF-II, directions on using it are not given in the manual. The useful Diagnostic Nurse supplied with the MPF-II runs a check on most aspects of the machine, including a display of its sound capabilities, which are essentially duration and pitch variations. Like the Apple, the MPF-II has a Trace facility to aid debugging. Unlike the Apple II the MPF-II is not expandable, but it will soon have a disc drive, the speech synthesis and sound-generation board mentioned earlier and Pascal and Forth. A Chinese-language unit has already been produced which allows Chinese-speaking users to work in the Dragon symbol system. Excellent plug-in ROM games are available, and the Invaders and Bridge provided with our system were of excellent quality. A £110 printer will also appear soon, producing 150 lines a minute in a 40-character-per-line format.

Conclusions

  • The MPF-II offers excellent value at around £200.
  • The fact that it is compatible with the Apple II means that an enormous amount of software is already available for it.
  • It is the only £200 microcomputer with true high-resolution colour graphics, and offers a Basic which until now is to be found only on machines as expensive as the Apple II or a BBC Micro.
  • The excellent idea of having the option of either single-key entry or normal entry of key-words should mean that the MPF-II satisfies everyone.
  • It would make an excellent training machine, especially with its good, built-in monitor, but also a good
    home computer for the game player or a low-cost computer for the small businessman.
  • Clearly, anyone who has been attracted by the Apple’s facilities but not by its price will seriously consider this micro as an inexpensive alternative.
Table 1. Keywords
CHR$, ASC, LEFTS, RIGHTS, MIDS, POKE, PEEK, WAIT, CALL, USR, HIMEN, LOMEN, LIST, LISTx,y, DELx,y, REM, INPUT, INPUT” “, GET, DATA, READ, RESTORE, LET, DEF FN, GOTO, GOSUB, IF-THEN, FOR-TO-STEP, RETURN, POP, ON GOTO, ON GOSUB, ONERR GOTO, GR, COLOR, PLOT, HLIN, VLIN, SCRN, HGR, HCOLOR, HPLOT, HPLOTTO, HGR2, SIN, COS, TAN, ATN, INT, RND, SGN, ABS, SQR, EXP, LOG, PRTON, PRTOFF, HC, CONTROL, MA, MP, LOADT, SAVET, LOADA, SAVEA, LOADD, SAVED, DRAW AT, XDRAW AT, ROT, SCALE, SHLOAD, SPEED, TAB, SPC, POS, HOME, NEW, CLEAR, FRE(O), DIM, VAL, STRS, TRACE.

First published in Your Computer magazine, October 1982

Franklin Ace 1000 – Apple Work-Alike

FranklinAce

By Chuck Carpenter

Having one personal computer that will do most everything l want to do has always seemed highly unlikely. That is, until I tried the Franklin Ace 1000, an Apple work-alike computer from the Franklin Corporation.

By simply including a standardized, full size ASCII keyboard, the Ace 1000 comes close to meeting all my requirements, primary among which is word processing. Others include communications, hardware testing, and software development for business purposes (test, measurement and control, not accounting or inventory).

Let’s take a closer look at the Ace 1000; perhaps it will meet your requirements, too.

Features

One of the first things you notice is the size of the Ace 1000 assembly. Some of this added size is width necessary to accommodate the length of the full size keyboard. Inside, extra space is needed for the large power supply and the spacious main circuit board.

Extra space on the circuit board means more room between components and between cards in the expansion slots. With more room between parts, cooling is improved and heat related problems are less likely to occur.

Additionally, the power supply has a built-in fan, which is noisy but not objectionably so. Besides keeping the power supply cool, the fan circulates air inside the computer case to aid in component cooling.

Table 1 shows the published specifications of the Ace 1000. In using the system, I have listed some additional features which should be of interest to prospective purchasers and users.

Most significant is the full-size keyboard. It includes a sculptured design to aid the user, and the layout of the keys is similar to an IBM Selectric. All the key functions worked properly with the languages and programs I tried.

Keys on the keyboard are individually replaceable. Manufactured by Keytronics, the keyboard uses capacitive switches so there are no contacts to wear out. The “feel” is somewhat spongy with a certain amount of tactile feedback to the user. I am used to a keyboard like this so it didn’t bother me.

All keys on the keyboard are repeat keys. Consider how much help this feature is when using a word processor. Text editing involving extended cursor movement is greatly improved, for instance.

Two special keys called PAUSE and BREAK are included on the keyboard. These are especially useful in Basic and Pascal programming. PAUSE generates a CTRL-S and BREAK generates a CTRL-C.

Memory for the equivalent of a 16K RAM expansion card is included on the main circuit board. Slot 0 is not needed for this application. A cut-and-jumper area is included to allow you to use slot 0 if you need to.

Cassette capability is not included with the Ace 1000. However, space for the circuit components is included in the circuit board etch (see Figure 1). I suspected that some of the Ace 1000 features used the memory space originally occupied by the cassette input/output (I/O) routines, and on investigation this turned out to be the case. Therefore, the cassette routines are not available in the firmware. Because the Ace 1000 is not considered a hobby machine, the cassette interface was not included.

Figure01

Figure 1. Circuits for cassette interface are included in the circuit board etch. However, the cassette input/output routines are not included in the monitor firmware.

Booting with the Ace 1000 Master Disk allows you to enter Floating Point Basic in lower-case. (Similar to Basic-80 under CP/ M.) When you list a program the lower-case commands and statements are converted to upper-case. Any variables entered in lower-case remain in lower-case. Under control of the Ace 1000 Master Disk, a lower-case filename is saved in upper-case. Integer Basic is converted directly to upper-case as you type.

When you boot with an Apple II Master Disk, you can enter Floating Point Basic in lower-case but not disk operating system (DOS) commands. Also you can’t save a program using a lower-case filename. For Integer Basic, you must press the shift lock key and enter everything in upper-case.

Otherwise, the operation and functions of the Franklin Ace 1000 are the same as the Apple II. A few minor problems arise because of the differences in keyboards. These will be discussed in more detail later. Table 2 is a summary comparison of Ace 1000 and Apple II features.

Hardware

Generally, the hardware is much like that of the Apple II. Power supply capacity is greater – about 65 watts for the Ace 1000 and 40 for the Apple II. Memory expansion (16K) is built in, or you can use slot 0 for memory expansion of your choice. To use slot 0, you make cuts to a designated block on the main circuit board.

There are several other memory options you can select through cuts and jumpers with this board option too. They are described in the User Manual. A reset button is provided under the left front edge of the case.

Operating the Ace 1000 is much like running an Apple II. I removed all the cards from my Apple – except the language card – and inserted them in the Ace 1000. Without exception, all of them worked.

I used the dual drives from my Apple for most of the test. Drives available from Franklin are Micro-Sci drives (reported to be manufactured under license by Franklin). I tested single Micro-Sci drive and controller and both worked without any apparent problems.

To gain further assurance I tried a sampling of software from my collection. Other than the minor problems alluded to above, everything worked. Table 3 summarizes the peripheral cards and software I used in the evaluation of the Ace 1000.

Software

Because most all Apple programs expect upper-case input, you must press the shift lock key to make them work (the minor problems). For instance, with Super-Text, the character X is used to print a file. A lowercase x wouldn’t execute. Furthermore, a filename typed in lower-case wouldn’t save. Upper-case filenames worked fine.

Another difference, again with Super-Text, concerns shift key operation. With the Apple II and a Videx Keyboard Enhancer, a certain key sequence is required to make the shift key work typewriter style.

By experimenting, I found a sequence that performed a similar function with the Ace 1000 keyboard. First, ADD mode is selected. Next, the shift lock is pressed, followed by a CTRL-C. Now the shift lock or shift key generates upper-case characters. Using a CTRL-P, the code for starting a paragraph, caused the steps just described to terminate their response. My solution was to use the tab function to indent paragraphs.

In addition to the Super-Text word processor, I tested Word Star running under Apple CP/M. My test was rather limited but showed that it worked at least enough to write a short letter, save it, recall it, and make local and global changes.

Included in the Ace 1000 service manual is a patch for the Applewriter II word processor. The patch lets you modify Applewriter so it will recognize the keyboard features of the Ace 1000.

Software provided with the Ace 1000 is limited to a Master Disk. Most of the programs are utilities and are much like those included with DOS 3.3. Each program is described in the Users Manual. Diagnostics are also included on the master disk. These utilities will help you locate a problem should you experience difficulty in operating the system.

Except as noted earlier, all programs from the Apple II master disk worked. Integer Basic was loaded into the expansion RAM and it worked too. In fact, the utilities such as the mini-assembler and those from the programmer’s aid ROM worked very well.

Along with a check on the machine language utilities, I tried PEEKs, POKEs and CALLs from the Integer and Floating Point Basics. As expected, as long as no routines from the cassette I/O are used, all access to memory locations functioned properly.

Documentation

Documentation is rather sparse. The Users Manual is all you get. If you want to learn any more than how to operate the machine, look elsewhere. There are no descriptions of programming languages included in the manual.

In fact, there is less information in the Ace 1000 manual than there was in the first Apple II manual. At least the original Apple manual included memory usage, a summary of machine language and Integer Basic commands, and sample programs. I expect some improvement in the area of documentation very soon.

If you are considering purchasing the Ace 1000 as a second Apple-like computer, all you need to know is how the new system works. More than likely you will already have all the documentation you need to describe programming languages. If Ace 1000 will be your first machine, locate and purchase as many of the Apple II manuals as you can.

Conclusions

For those who want to use a personal computer as a word processor, the Franklin Ace 1000 is an excellent choice. The full size upper and lower-case keyboard is a delight to use. This review was written on the Ace 1000.

If you want a system, as I do, with flexibility, ease of expansion, and functional utility, the Ace 1000 will do the job quite nicely, especially if you are considering a second computer and already have documentation. Software for personal, business, professional, and development applications is available through many sources.

If you are interested in color graphics, however, forget it. The Ace 1000 generates only shades of grey and black and white (assuming you use a black and white monitor). A color adapter board is “soon to be available.” It will plug in to one of the expansion slots.

Based on my evaluation of the computer, I suspect that any software or peripheral that will work on an Apple II, will work on the Franklin Ace 1000.

The Apple II is probably to be at the peak of its product life right now and, the Ace 1000 should help to stimulate the market for Apple-compatible products. The new Apple work-alike products won’t injure the Apple market, they will enhance and sustain it.

One caveat: make sure the company manufacturing your Apple work-alike will support the product. Franklin appears to be establishing the required support network. High Technology, the local distributor, has been involved with factory training programs through Franklin. In turn. High Technology provides training and support for its dealers.

Franklin Computer Corporation, 7030 Colonial Hwy., Pennsauken, NJ 08109

Table 1 – Franklin Ace 1000 Specifications
Microprocessor 6502 at 1.022 MHz
Text 40 characters x 24 lines standard

5 x 7 upper/lower case

Direct lower case entry

Normal, Inverse, Flash

Graphics Black and White only

40 horizontal x 192 vertical

40 vertical with 4 text lines

Hi-Res Graphics (B&W) 280 horizontal x 192 vertical

160 vertical with 4 text lines

Cost $1530 Processor

$579 Drive & Controller

$479 Drive without Controller

EME/RF1 FCC Class A Service

Class B pending

Memory 64K bytes of RAM

250ns access time

6 EPROM sockets (2716)

Keyboard 72 keys upper/lower case

15 key Visicalc pad

2 special function keys

I/O Joystick/paddle connectors

8 expansion slots

Physical 17.75” x 4.5” x 19.75”

15 pounds

Power 115 VAC, 60Hz, 65 Watts

 

Table 2. Franklin Ace 1000 Comparison
Item supplied Apple II Ace 1000
Full upper/lowercase keyboard No Yes
Cassette interface Yes No (1)
Color graphics Yes No
Black and white graphics Yes Yes
Visicalc 15-key keypad No Yes
80-Character columns (2) No No
Power supply with fan No Yes
64K RAM memory (3) No Yes
Mini-Assembler (4) Yes Yes
Floating Point routines (4) Yes Yes
Sweet-16 interpreter (4) Yes Yes
Programmer’s aid routines (4) Yes Yes
(1) Circuitry of components included on the main circuit board

(2) Videoterm or equivalent board suggested

(3) 16K equivalent expansion board built-in to Ace 1000 main circuit board.

(4) Available with soft-loaded Integer Basic or Integer Basic ROM card

Note: A ROM card or memory expansion card can be used in slot 0 if appropriate cuts-and-jumpers are added to the selection block area of the main circuit board.

 

Table 3. Franklin Ace 1000

Peripherals and Software Tested

Peripheral Software
Microsoft Z80 Softcard Super-text II
Apple Controller 2 Drives Sargon II
Wesper 80-column Video Board Space Eggs
Mountain Computer Clock Gorgon
Wesper BPO Printer Buffer Universal Boot Initializer
Apple Parallel Printer Board Flash! I/B Compiler
Micro-Sci Controller & Drive (1) S-C Assembler 4.0
Hayes Modem II Data Capture 4.0/80
  CP/M & Basic-80 (MBasic)
MPC SIO Serial Printer Board Locksmith 4.1
  CP/M & Wordstar W/P
  Visicalc
  Pascal
(1) Optional drive supplied by Franklin

First published in Creative Computing magazine, January 1983

This is the BBC…

Thisisthebbc

Walk into a school computer room and the chances are you ’ll see a room full of BBC computers. Love it or hate it, the BBC Micro is a part of the British computer establishment. Yet the remarkable success of the machine contrasts with the failure of Acorn, the manufacturer, to cash in on what was a state-of-the-art computer. Peter Scott tells the story of the BBC…

The ‘80s have proved to be the decade of the micro, and in many people’s minds the definitive micro is the BBC. The machine was first conceived at the beginning of the decade, when the BBC produced a specification for a home computer. This machine was to be available in the shops and was to accompany their planned computer literacy project. This called for easy networking, lots of user ports and a fast and structured BASIC.

Acorn Computers had some success with the idiosyncratic Atom, and their planned Proton machine seemed to match the requirements of the BBC spec. After frantic efforts to add a teletext mode, the Proton was seen and accepted by the BBC, became the BBC Micro and 12,000 units were ordered.

To this day, there are rumbles of discontent about that decision. Sir Clive Sinclair made public his unhappiness about the rejection of his ZX-82 by the Beeb, but that machine, re-titled the Spectrum, soon went on to dominate the games market.

The BBC Micro went on sale in early 1982, but Acorn had massive difficulties meeting the demand, which was fuelled by the BBC TV ‘Computer Programme’. The TV series was ridiculed by the computer-literate as patronising, but added momentum to the then mushrooming home micro market.

There were two versions of the BBC Micro – the 16K Model A and 32K Model B – and demand for the latter caught Acorn unawares. As thousands waited up to four months for delivery, Acorn even increased the prices of both versions to £299 and £399 respectively. The Model A was soon to die, due to its chronic lack of memory.

Acornsoft, set up to support the new machine, announced several programs that are still classics, such as Defender, which was rapidly re-titled Planetoids to head off legal action. The BBC was universally acclaimed as fast and powerful – the Amiga of its day. Programs such as word processors, spreadsheets and tool-kits became available on ROM, a fundamental feature of the machine, and one made wide use of.

One problem was the price of the machine. Acorn solved this soon after with the Electron, a £200 cut-down BBC Micro. Yet again, demand exceeded supply, giving many sales to Sinclair and Commodore during that year’s Christmas boom. Nevertheless, Acorn went from strength to strength, and just a year after the launch, over a hundred thousand BBCs had been sold.

Bad memories

Then things started to go wrong. The BBC Micro was seen as overpriced and short on memory, and flopped in the USA. The Electron finally became widely available just when the massive boom in home computers started to fade. The Spectrum was cheaper and had more games available, and the Electron didn’t take off as well as Acorn had hoped.

Schools continued to buy BBC Micros, funded by the Government and encouraged by the burgeoning software base. By the end of 1984, Acorn was in financial trouble. Ironically, that year produced one of the classic BBC games of all time – Elite.

Christmas that year was a disaster. The Spectrum and Commodore 64 trounced both the BBC Micro and Electron in sales. After yet more losses, Olivetti bought first 49 per cent and then another 30 per cent of the ailing Acorn.

Acorn tried to fix one of the major criticisms of the BBC Micro by launching the BBC B Plus, with 64K of memory. It sold poorly due to its £499 price tag and was generally ignored by the software companies.

The next attempt to recover credibility and the share of the market was the BBC Plus 128 – yet more memory and freebies, but this did little to help sales. Acorn seemed to have little time for the home market, concentrating instead on the business and educational side. This attitude still prevails today, much to the annoyance of the hundreds of thousands of home users. Despite Acorn’s mistakes, there were almost 500,000 BBCs sold by the end of 1985.

The BBC Master was launched in the next year – more memory, a new keyboard, built-in ROM software and improved BASIC were all welcome, but again the price wasn’t right. The cheaper Master Compact, complete with 3.5″ disk drive and lack of user ports, followed.

But now the competition was the Atari ST and Commodore Amiga, and the public ignored the BBC in droves. The Electron became harder and harder to buy, and soon was discontinued.

Acorn needed an answer to the 16-bit machines. It came up with the Archimedes, massively powerful and with a revolutionary 32-bit RISC chip, running an uprated BBC BASIC and supported once again by the BBC name and logo on the cheaper machines. However, almost £1,000 must be spent to buy the basic model – hardly a home machine. Will Acorn price themselves out of the market again?

From little Acorns…

The situation today is little changed over that a year or two ago. There are rumours of a cheap Archimedes ‘200 Series’, with built-in disk drive, simpler chip layout and TV modulator, competing head-on with the ST and Amiga. The Master is still on sale new, and can be had for around £400 mail order. Many companies offer substantial bundles with the Master, such as disk drives and software, so shop around.

Second hand BBCs can be had for £200-£300, complete with a disk drive and large amounts of software. Second hand Electrons can also be had for less than £100, but there are still some new ones around, some for as little as £29! Check the BBC magazines for small ads. BBC games software is still produced, and can normally be bought via W H Smiths or independent computer stores. Superior Software dominates the BBC games market with conversions of hit games such as Barbarian, Last Ninja and Barbarian II. I must declare an interest here – I converted those games!

The reasons that the BBC is still supported are threefold. Firstly, the specialist press – four mainstream magazines for the Acorn range is more than even the Spectrum manages. Secondly, the more technical nature of its owners, who are rarely the 12-15 year old games players that dominate other home micro markets. Finally, the vast educational influence spurring parents to buy their children the same computer as they use at school.

Many programmers and major games started life on the “dull old Beeb” (to quote from New Computer Express]). Elite, Sentinel and Revs are examples of classic games which first emerged on the BBC Micro, and the Archimedes already has Zarch/Virus to its credit.

The BBC market isn’t dying, as so many have predicted over the past three or four years. Sales this Christmas improved over last year, and that is within the context of shrinking sales for the other 8-bit machines. There is a huge base of software, from business through educational to entertainment, and schools still keep buying ’em. There’s life in the old Beeb yet!

The BBC Spec

There are many variants of the BBC Micro, but the basics remain constant. An 8-bit 6502 central processor is at the heart of the machine, combined with a fast and structured BASIC, giving the BBC a speed second to none in the 8-bit field. BBC BASIC is regarded as a standard by many, and provides a built-in assembler, making the BBC very easy to learn to program.

There is a meagre 32K, eaten into by the seven graphics modes which take up anything from 1K (teletext mode) to 20K for a 160 x 256 16-colour mode. The disk operating system also takes up memory, leaving as little as 8K free for programming. Although there are 16 colours in theory, there are really only 8, plus 8 flashing combinations. Highest resolution is 640 x 256 in 80-column 2-colour mode.

The B Plus, Plus 128 and Master series have more memory, and newer pieces of software such as word processors make use of it. On the Master, for example, extra memory called shadow RAM can be used for the screen and disk operating system, leaving 29K free in all modes. Games software occasionally makes use of the extra memory for extra sound or graphics.

The video chip permits limited (and juddery!) hardware scrolling, but no hardware sprites. The 3-channel plus white noise sound chip is similar to that in the Amstrad CPC or Spectrum +2, but lack of memory usually means little use is made of it.

The BBC is well-provided with user ports, although many are non-standard. The joystick port is analogue, meaning normal 9-pin joysticks need an adaptor to work. Few games offer joystick options due to tight memory.

The Electron has one-channel sound, little hardware scrolling, no user ports, no teletext mode and is 20-50 per cent slower depending on graphics mode. Despite this, the hardware is better than the Spectrum, for example.

Box of dates

  • 1980 – The BBC draws up plans for an adult computer literacy series.
  • 1981 – Acorn’s Proton becomes the BBC Micro; 12,000 units ordered
  • 1982 – BBC Micro goes on sale
  • 1983 – The Electron – a cut-down BBC – launched; 125,000 BBCs sold by the end of the year.
  • 1984 – BBC flops in US; Spectrum and Commodore heavily outsell BBC in Christmas sales.
  • 1985 – BBC Plus 128 launched; half a million BBCs sold by the end of the year.
  • 1986 – BBC Master launched
  • 1987 – Acorn unveils the Archimedes.

First published in New Computer Express magazine, 11th March 1989