The Microbee Archive

Last modified 26th May 2004.

Once upon a time, many years ago ... well in computer terms, it may as well be ancient history ... there was an Australian computer called the Microbee. Several hundred thousand were made in the 1980s and sold to users all over Australia and to users as far away as Sweden. It was one of the first computers to make big inroads into Australian schools and many an Australian computer nerd cut his/her teeth on a Microbee.

The story started with a company called Applied Technology which had been selling electronic components in Hornsby, a northern suburb of Sydney. In the late 1970s, the S100 computer was very popular. Such machines were made around a card cage with a 100 way buss (hence S100). The budding computer constructor (or computer company) would gather together a number of cards (processor, video, memory, RAM, ROM, disk controller (floppy of course) or perhaps a cassette controller and then when it was all put together, hopefully the result would run BASIC or of you were rich, CP/M - the DOS of the time from Digital Research. Every month I would scan the electronics magazines and ogle at the adds for these machines but no matter which way I added it up, the price of admission was always too high. My brother in law bought one with a massive 48k of memory and two floppy disk drives. It cost him about A$14,000.

About this time, the early Apples, TRS80s, and Commodore 16 and 64 were making them selves felt. They were small, relatively cheap and offered home computing to the adventurous. Into this market, Applied Technology introduced a kit computer - The Microbee. It arrived in a plastic bag as a circuit board and lots of components. It was definitely not for the "solder challenged". A friend bought one, assembled it, switched it on and .... nothing - not a sausage. Luckily he was an electronics technician and had the equipment and skill for some serious trouble shooting. He traced and measured and eventually decided that the necessary signals disappeared under one particular IC but did not appear out the other side. He lifted the IC to discover that the tracks were missing under it. A finger print, some dirt, and the tracks had never been there. Some patches were applied and BEEP, his 'Bee was alive.

These early Microbees had A Zilog Z80 processor at 2 megahertz, either 16 or 32 kilobytes of battery backed static RAM (6116), and provision for up to 32k of ROM (a Z80 can address 64k) . They came with Microworld Basic in ROM and a Monitor program gave direct access to the processor. The screen could display 16 lines of 64 programmable characters which could be used to provide limited high resolution graphics. An Editor Assembler (EDASM) in ROM was soon available. This could even be used as a simple word processor and files could be stored to a cassette recorder via a special cable. The machine supported standard monochrome monitors with a composite video signal.

So successful were these machines, that before long, Applied Technology was selling them ready to go in a new two tone plastic case. Power was from a 10 volt 1 ampere (later 1.5 ampere) DC plug pack. This was regulated on the board by a number of standard 5 volt regulators. I/O provided were parallel, serial, video, cassette in and out. Later versions gave access to the machine's buss via a rear 50 way connector.

Microbee 128k standard scan
This image was made by placing a Microbee into my scanner. At the present time I have -

Pre-Microbees - S100 computers

S100 Z80 based computer with EPROM burners and David Griffiths Operating system (DGOS) to operate a cassette tape. The power supply is something to behold. It is a linear supply with a LARGE transformer and several large capacitors. One could almost weld with it. I hope to get this beast running but it is in a rather untidy state at present. (It is now - Dec 2001 - at the Unnamed Computer Museum).

ROM based Microbees

32k Home built - 2mHz clock, Z80 - now with a collector in Sydney

S_mbee01.jpg - 25283 Bytes

This is the very earliest Microbee - built from a kit and with a metal base plate, blue circuit boards and a one piece plastic case. The badge is from a later Microbee printer.

S_mbee02.jpg - 21166 Bytes

And this is what the Microworld Basic looked like on the early machines.

32k IC (with EDASM)-3.375 mHz clock. All later Z80 Microbees run at this speed though many were over clocked up to 6 mHz.

32k Personal Communicator (with Basic, Telcom terminal program and Wordbee - a word processor in ROM)

32k PC85 (Word processor, Basic, Spreadsheet, Database in ROM) - the last of the line for ROM based machines - very neat and with built in networking.

Disk Based Systems

56k Microbee - the first CP/M disk based systems. Two 5.25 inch floppy drives in a metal case with a heavy linear powersupply and a "vanilla" CP/M. Provided with Wordstar, MS Basic and Multiplan. Microbee's first serious computer. A friend ran the books of his dental practice with one of these. He loved Multiplan (spreadsheet).

64k Computer In A Book. You have to see it to believe it. Low cost CP/M for the masses. One (or optionally two) 3.5 inch single sided drives each mounted in an aluminium box which is covered to look like a large book. The drive stood on end beside the monitor and the manuals were also supplied in a similar package. The optional "Volume 2" contained a second drive. A switch mode power supply was in the first drive and supplied the computer and the drives. Some people mounted the drives on a book shelf among some books but this tended to cause the power supply to overheat with disastrous consequences.

128k Standard, 2x5.25 386k floppy - limited PCG graphics. A development of the CP/M operating system added an easy to use "shell" plus a number of easy to use utilities. These machines were supplied with a package of software including MS Basic, Wordstar 3.3 and MS Multiplan. A very useful little machine.

S_128k01.JPG - 41487 Bytes

The Premium 128k machine sold in very large numbers - usually with 2 x 3.5 inch DSDD drives. It boasted improved graphics over the earlier machines, colour as standard and many other detailed improvements. Unfortunately, the Premium machines were plagued by key switch problems and most of my Premiums have had this problem. This machine is missing its gold Premium badge but the cursor keys at the left and right give it away as a Premium.

128k Premium, 2x3.5 776k floppy - more graphics RAM plus colour to drive a CGA monitor as standard.

128k Standard 10 meg hard disk system - for the office. Similar to the other 128k systems but with the convenience of a 10 meg hard drive. (That's 0.01 gigabytes!!!) Sounds small but the programs were small too and you can store an awful lot on one of these.

128k Standard 10 meg Starnet Server (serves 16 Starnet stations) - for the school or office

64k Standard Starnet workstation - for schools and offices. These machines were disk less but could run disk based software from a server.

128k Premium "Overdrive" single drive system. The drive is mounted on the top of a standard Microbee case. An attempt at a cheaper machine forschools.

S_256tc01.JPG - 46077 Bytes

The 256TC syyled machines appeared late in the life of Microbee. It first appeared as the Teleterm - a Viatel terminal, next as a full blown machine - the 256TC seen here and finally as the Matilda with its 8088 processor, IBM compatibility and Z80 for running CP/M. 256TC A completely new packaging of the original Z80 Microbee - new keyboard with numeric keypad, new main board, more memory, real time clock (the battery leaks!) better graphics and the disk drives in the computer like modern laptops. Very like the Amiga 600 in size and layout.

plus several more.

S_gamma02.JPG - 28484 Bytes

The Microbee Gamma was to have been the start of a whole new line of high performance computers form Microbee. Unfortunately the high cost of developing it sent Microbee to the wall. It had a Motorola 68000 and two Zilog Z80s - one as a graphics co-porocessor.

Late in the life of the company, a new machine - the Gamma was being developed. This machine never made it into the market place as the cost of developing it ruined the company. It was a brave attempt and the prototypes which did appear showed great promise. It had 1 Motorola 68000, 2xZ80s and was intended as an Amiga class machine. Its operating system was UNIX like and it could also run CP/M software on one of the Z80s. The other Z80 was used as a video processor.

I had until recently what is possibly the second last Microbee Gamma in existence. The machine is now with a friend and I still have a blank printed circuit board. Oh yes, the other one is in a Museum in Melbourne.

Some other ancient machines I have.


The Amiga is not a Microbee but like the Microbee, it did not have IBM written on it and as a result had a hard time in the marketplace. Amigas were and are great machines and I have several in my collection -
Amiga 1000 - the original Amiga. 68000 processor, 880k floppy, 4096 colours plus lots more. I have 2 PAL versions. There were also NTSC versions. If you can, look under the lid. The signatures of the original team are there including "the dog". Neat.

Amiga 600HD - a later Amiga for home use but without a numeric keypad. 50 meg HD. Probably designed by accountants.

Amiga 1200 - later AGA (advanced graphics adapter?) machine. Has 110 meg HD and Motorola 68020 processor. If someone out there knows how to connect this beast to the Internet, I'd love to hear from you.


Ol' Big Blue would have us believe it created the PC but we know better don't we. It did, however design an architecture which is the basis of today's Intel/Windows machines and which goes to prove that you don't have to be the best to win Remember Betamax - Sony's technically superior videocassette?.

I had - until recently - the following genuine IBM machines -

IBM PC - the original one - ROM Basic, cassette port, 5 x 8 bit slots, 16k memory on board - max 64k (4164 chips), Intel 8088 processor at 4.77 MHz. Monochrome Display Adaptor (text only) or Colour Graphics Adaptor (CGA) - four colours!!!

IBM PC XT - the first usable one - HD of 10 or 20 megs - 360k floppy, still an 8088, 8 x 8 bit slots 640k memory

IBM PC AT - serious power at last. 80286 Intel processor at 6 MHz, 1.2 meg 5.25 inch floppy, 7 x 16 bit slots and 1 x 8 bit slot, 40 meg HD. EGA (Enhanced Graphics Adaptor) 640 x 350 x 16 colours. WOW.

I also have several other strange machines including a Commodore Pet (looks just like Deep Thought for all you Hitchhiker's Guide fans), a Dick Smith System 80 (TRS80 clone), some Hewlett Packard 9845 machines - large and powerful in their day and lots of other junk including a box of memory - I/O - real time clock cards for the original IBM PC and XT. Really useful. Anyone want one?

If you are having problems with your Microbee or other ancient computing device, give me a yell and I may be able to help.

I will give pictures and more detailed specifications for all these machines over the next few weeks and months.

Email me here if you want more information or for corrections etc.

Leave a message in my Guestbook (below in Michael's Land Rover Page) - it will help me know what you what to know.

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