Computers in the past were a lot different from their modern counterparts. On this page I have selected two computers from the early 1980s and have looked at how they used to work and just how different the home computing experience used to be.

The Sinclair ZX81 (1981) (photo from Wikipedia)

Sinclair ZX81 1K computer - 1981

This was the first popular and affordable home computer in the UK. In fact, this machine represents a milestone in early computer history. The ZX81 was a development of the ZX80, which was released a year earlier, but was much more basic even than the ZX81 and which had a tendency to overheat. As was standard practice in those days, the ZX81 would be connected to a television.

It’s perhaps true to say that the ZX81 is somewhere along the transition from pocket calculator to a modern home computer – it is certainly more computer than calculator, and it certainly wouldn’t fit in your pocket, but the graphics were very basic and the basic model came with just 1K of RAM.

A ZX81 cost £70 when it was released in 1981. Or, for £50 you could buy a ‘kit’ where the computer was supplied as bits (keyboard membrane, circuit board, numerous resistors and capacitors etc.) which required you to use a soldering iron in order to put it together.

When the ZX81 was switched on there would be a blank screen with a "K" symbol, with the computer waiting for you to type in text. If for example you wanted the computer to print "THE QUICK BROWN FOX" on the screen you would do the following:

• Firstly press P on the keyboard which brings up the word PRINT followed by a space.
• The cursor changes to an inverse "L". press SHIFT + P and you get the opening quotation marks (") that you require.
• Type in THE QUICK BROWN FOX. However, if this is done too fast the computer will fail to keep up with your typing speed.
• Press SHIFT + P again for the closing quotation mark (").
• Press the NEWLINE key.

The ZX81 had a simple screen of 32 × 22 characters and only black and white were available as colours. In fact, there was only 1K of memory available for the screen. The screen character set was in the illustration on the left. The characters shown represent everything that you could type - any punctuation marks not shown were not available. In addition, there is no lower-case alphabet. Note the block characters on the top two rows. These formed the basis for any graphics output from the computer – pictures would be made up of these block characters.

The keyboard has much fewer keys than a modern equivalent. Instead of the ‘delete’ key there is RUBOUT (SHIFT + 0). Even the cursor or arrow keys can only be accessed through SHIFT 3 to 6. And the punctuation marks are in different places – so a colon (:) for example is SHIFT + Z.

Any software was loaded from cassette tape. This was the standard recording medium in the early 1980s for both computer software. An example game, a version of Pacman (© 1982 Artic Computing Ltd), is shown on the left.

There was also a simple printer available for the Sinclair ZX81. To look at, it was not too dissimilar to a roll of paper coming out of a financial calculator.

My "ZX81 VDU" font

Here you can download for free a TrueType font that I have created which replicates the letters, numbers etc. that were displayed on the screen of the ZX81. To download click here

Other ZX81 fonts exist on the Internet, but in my version I have stuck to just those characters that existed on the original computer. So no ampserand (&), no 'at' sign (@) and not even an exclamation mark (!). Also, I have tried to ensure that the inverse symbols (white text on a black background) are true to the original. The spacing should also reflect the original appearance on the screen.

I have also tried to make some of the inverse symbols and graphics characters accessible using the keys available on the normal modern computer keyboard. So some of the key mappings are as below. On my keyboard, the result is that all of the inverse symbols 1 to 8 are all in the same area. It is difficult to map the ZX81's original character set to the modern computer keyboard, as the two are very different, but hopefully the end result will work well.

© Matthew Eagles 2008-2015

 

Sinclair ZX81 character set
PacMan game on Sinclair ZX81

The Acorn Electron (1983)

Acorn Electron 64K computer - 1983

This computer was effectively a scaled-down version of the BBC Micro, which was a very popular and capable computer of the early to mid-1980s. Once again, the Acorn Electron was very different to anything that is produced nowadays. This time, when you switch the computer on, you hear a beep and you see a screen saying something like "Acorn Electron BASIC".

The word "BASIC" on the screen indicates that the Electron is expecting you to write a computer program in the language called BASIC, which was the standard pre-installed programming language. In some respects, there is not much change from the Sinclair ZX81 – the start-up is immediate, and the computer expects you to give it some instructions (i.e. program it) straight away. However, this time you have more memory available, and more graphics capability.

Even so, the graphics were still very basic by today's standards, with only 8 colours available and a screen resolution of 640×240 in high resolution (Mode 0), 320×240 in medium resolution (Mode 1) and 160×240 in low resolution (Mode 2). The reason for these limitations is because in the 1980s the memory required to store the screen display was a significant proportion of a computer's total memory. The Electron was a 64K computer, of which only 32K was writable memory (i.e. RAM), and even the basic displays listed above would take up to 16-20K of memory, leaving only 12-16K for programming, pre-installed software, or for storing any other data.

It's probably also fair to say that typing anything on the keyboard is easier to do than it was on the ZX81. The keyboard is laid out a little differently from that of today (some of the punctuation marks have moved), but you now have more of a full character set with lower-case letters etc.

Games were very popular on 1980s computers, although they are a world away from the world of Playstation, Xbox and Nintendo Wii of the early 21st century. The graphics were far more basic, although the games were still plenty of fun. On the left is a screenshot of Snapper, a variation of Pac-Man (written by Jonathan Griffiths, © Acornsoft 1983) .

However, playing a game was not as simple as double-clicking on a file as would be done with a modern computer. Games for the Acorn Electron were on cassette tape, and so there would be a small tape recorder sitting next to your computer. And depending on the size of the game, this could take three or four minutes to load. Add to that the possibility that the tape would become distorted or physically damaged over time – it was not uncommon for the computer to 'miss' a section of data while trying to load a program or game from tape, and many of my tapes (especially for storing computer programs) became unplayable over time.

The Acorn Electron had nearly all the same features that the BBC Micro has. The main differences were that the BBC Micro was available with up to 128K memory, it was easier to interface other devices such as a printer, and it had an additional display mode (Mode 7) which could be used to create Teletext-style displays such as those in the "THIS WEEK" page of this website.

My "Electron Plus" font

I have recreated the typeface that appeared on the Acorn Electron's screen – and added some extra characters. By default, the characters appear as they would on a 40-character screen, but can be elongated or compressed to look as they would on a 80-character or 20-character screen. The TTF font file is free to download here. A sample is shown below.


© Matthew Eagles 2008-2015

Acorn Electron character set
Acorn Electron - demonstration of screen modes
Snapper game