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Comparison/evaluation of some homecomputers from 1980-1985

Note: this page is not nearly finished and may be inaccurate in a few places.

The BBC B was my first computer and also the first usable computer I had access to (contrary to what you might expect, I didn't find my dad's ZX80 usable ;-) ), and remains my favourite 8 bit machine after trying out a bunch of others... (nostalgia would probably prevent any other machine becoming favourite, but, I'm not blind to the negative points of this machine, nor to the positive points of others)

I loaned a bunch of machines with software, books and add-on hardware from a friend, and was given a few others (ZX spectrum & ZX81). On this page I will compare and give the good and bad points of the BBC B and the other machines that I tried (mostly during 2001-2002). All this from a perspective of 1983/1984 where that's relevant (e.g. prices), or the entire period up to the machine was released (i.e. using all machines released up to that time and the ones that would appear shortly after as a benchmark) for criticism on functional specifications.

The bad points outnumber the good points for all the machines in this list! That's probably just because of my emphasis on programmability and user friendliness... But, they are all real bad points and as you can see, there are no machines that are good in all aspects. They all have large problems and it's obvious that no single machine at the time could be recommended for all people. I remember I had a hard time choosing a computer in 1983, and this page shows that was inevitable!

If you have any suggestions, comments or good- or bad points that should be mentioned, send me a mail!

I tried the listed machines imagining:

to see if I liked them, the manuals etc. For this, it is nice to have a machine in the original box, you can then really get into the mood of "I just bought this new computer, lets see what I can do with it" :-)

Note: with 'gbp' I mean the £ (UK)

List order in date of release of the machine:

DAI

Specs: Real keyboard, 24K ROM, 48K RAM,...

I still haven't found one so I can't tell anything about it from experience!

Sinclair ZX80

Specs: membrane keyboard, 1K RAM, 4K ROM...

All comments at the moment are my thoughts about it at the time:

This was my dad's, and the first computer I used. I was NOT impressed! I remember the screen flickering at each key press and totally being gone during program execution. Integer calculations only. There was a later 8K Basic extension with most of the functions of the ZX81, including floating point calculations (I believe only the slow-mode was not available in such an upgraded ZX80); This upgrade was probably from the time of the ZX81, or was it released before the ZX81?

I remembered something else that's quite funny: When we first used it, I thought the machine was broken, because the screen display went away at keypresses. So, my dad phoned the shop (somewhere in Rotterdam, where it was quite cheap, presumably because the ZX81 had just been introduced, or maybe it was a trade in, as it didn't come with a box), and found out that that was normal for the ZX80! Only the ZX81 had the option to give a display at all times. Imagine that, you're sure the computer is broken, then it turns out this is normal...

Acorn Atom

Specs: Real keyboard, 1MHz 6502, 2K RAM + 8K ROM minimum, expandable to 12K RAM + 16K ROM for a standard tape machine, or 15K RAM + 20K ROM for a machine with disc pack (the disc pack includes another 3K RAM for workspace and 4K DOS ROM); Further expansion is possible by whatever you place in the externally mapped (offcard, usually external but can be placed internally too) space. Other expansions include a BBC Basic conversion card (incompatible with the disc pack btw.) and a colour card.

Introduced mid 1980, this machine does not have colour, and very limited sound. It has a reasonable keyboard in early models and a good one in later models, provides good facilities for programming and for expansion, but it's clearly not a desirable machine for people contemplating buying a computer in 1983/1984, who often wanted to play games. This is a DIY computer, with lots of technical information provided standard in the 'technical manual'. Mid 1982 it was essentially obsolete, superseded by the BBC model A, Commodore 64 and Sinclair Spectrum.

Good:

Bad:

Verdict: For 1980-1981 a good machine. Obsolete when the BBC computer and the ZX Spectrum arrived.

Sinclair ZX81

Specs: membrane keyboard, 1 K RAM, 8 K ROM, RAM expandable with e.g. the standard 16K RAM pack.

The keyboard is awful, but with the floating point variables and the slow mode that gives a screen image while running a program (or just pressing a key!) this is much more usable than a ZX-80, from what I remember from that machine, long time ago! This machine is not at all comparable to the other homecomputers, the keyboard makes this just barely usable, adding a proper keyboard would have cost so much that it would have been more prudent to buy say, an Acorn Atom... (except that the ZX81 had much more commercial support, although I'm not sure if much of this may have come at a time when neither the ZX81 nor the Atom were of interest to new buyers, say mid 1982 on? Check...

Good:

Bad:

Verdict: It was cheap, and that's about the only good point. A programmable calculator was cheaper, more powerful for many purposes and had just as much memory. When the ZX Spectrum arrived mid 1982, there really was no reason to buy a ZX81.

Acorn BBC B

Specs: Real keyboard, 32K RAM, 32K ROM, expandable with 3x16K sideway ROMs, more with a ROM expansion board. Other internal expansions that appeared later are shadow RAM boards (screen RAM no longer uses up main memory) and 4MHz accelerator boards.

Excellent computer, but too expensive. Not enough RAM. It should have come standard with 16K sideway RAM, which would have provided enormous potential for large games. Perhaps even 64K total, with the OS copied to RAM or swapped in/out as with paged ROMs (the C64 can do that).

To reduce cost, the main PCB should not have had the provisions for the econet and diskinterfaces, but instead slots as used on the Apple 2 and Atari 400/800. The model A should have come with 32K RAM and with the PCB simplification it could probably have been sold for the original 235 gbp, perhaps a bit more. It probably would have been more succesful than the model B in that case... Btw, I'm sure the models A & B could both have been sold for less anyway; there's an interview with an Acorn guy in an Asterisk (dutch) where he talked about the money wasted at Acorn (sending a BBC computer by taxi to a dealer a hundred kilometres or so away, that sort of thing).

Good:

Bad:

Verdict: Best programming machine until late 1985, but from early 1984 on it was definitely too expensive and more powerful machines already appeared (Sinclair QL). Acorn sat on their laurels, relying on the money guaranteed from the educational support schemes (schools would have to pay just part of the expense of the hardware, government paying the rest) and did not develop successors/upgraded versions in time.

Commodore 64 (C64)

Specs: 1MHz 6510 CPU (almost the same as the 6502), 64K RAM, 24K ROM, real keyboard.

Good hardware (64K RAM, all usable through mapping, good sound, reasonable keyboard (mushy feel)), good value for money:

Good:

Bad:

Verdict: It's no fun programming with this machine, a shame as the hardware provides enormous potential, with RAM/ROM mapping done mostly the right way (no facility for multiple paged roms though). Extensions like Simon's Basic exist which are good, but non standard so you can't exchange programs with other people, and magazines will only provide listings in the crappy standard Basic. So, a good machine to play games but for developing programs it's useless (unless you were/wanted to be a commercial programmer).

Sinclair ZX Spectrum

Specs: Membrane with rubber keys, 16K or 48K RAM, 16K ROM (Basic + OS), Z80 CPU

Fill in... (Need to play more with it and read some more books!)

Good:

Bad:

Verdict: Good to learn programming and play games, overall the Spectrum is probably the best all round machine during 1982-1984 when one regards its cost, playing games, usefulness for programming and learning about computers.

Ti 99/4a

The precursor of this machine is the Ti 99/4 which has a simpler keyboard, not as good as the proper one on the 4a. Basic is very slow. An example: 6 sines calculated per second whereas a BBC micro does 40/s albeit at reduced accuracy. The accuracy can only account for a part of this speed difference. The CPU is 16 bit but has no real internal registers which kills some of the speed. Still, reports say a tms9900 is faster and has smaller equivalent machine code programs than a 8086. One problem is that in this machine only the ROM and a little bit of the RAM is 16 bits wide. The rest of RAM is 8 bits wide so many reads/writes need to be done in 2 pieces.

Haven't found good information on the tms9900 assembly language to see for myself what the speed would be for a given program implemented in tms9900 asm. Anyone have some assembler reference on the web?

Good:

Bad:

Add more...

Acorn Electron

Specs: Real keyboard, 32K RAM, 32K ROM, 2MHz 6502 CPU (not 1.79 MHz as various collectors say on their 'bragging lists'), no joystick ports, no cartridges/ROM expansion without an expansion unit.

The keyboard is better than the BBC's keyboard (at least for the BBC's standard type1 keyboard! for type 4 it may be a draw), and visually it is more attractive than the BBC micro; unfortunately those are all the good points compared to the BBC. The speed is awfully low, it's not faster than an Acorn Atom in most cases (but it does have good colour which the Atom doesn't have). Speed wise it's worst in the hi-res modes, where machine code will run 4.3 times slower than on a BBC (making it equivalent to a computer with 0.46 MHz 6502!). This really disappointed me. When I was looking for a machine in 1983, this was not apparent from reviews except in Acorn User (which I would not have bought/glanced at, not having any Acorn machine yet). I remember doing a speed test in mid 1984 at the dealer where I bought my BBC micro who had a computer attic, using a simple Basic loop, and being very disappointed by the 3x or so slow down in hi-res modes, but the 4.3 times for machine code makes the hi-res/hi-colours modes just about useless for anything! In the Basic speed tests, the Electron fares ok, but as ROM is accessed much faster than RAM (in particular because each byte has to be fetched in 2 goes, memory is organised 4 bits wide. What the hell were you thinking of when designing that, Acorn?), this is not a useful speed comparison for games. The result is that games for the Electron usually use MODE 5 (4 colours at 160x256) instead of MODE 2 (8/16 colours at 160x256) on the BBC, and still run slower. The slowness really shows even for games that use a 10K mode: E.g. Arcadians shows serious slowing down from 10.000 points onwards when multiple nasties come swooping down. On other games, the main problem is the lack of colours, they look very very dull compared to BBC versions. Sound is not great as there's just one channel, but this would not be much of an issue for most buyers, although other machines like the C64 and Atari 600XL provided good sound and generally superior abilities for game playing compared to the Electron for about the same price.

Good:

Bad:

Verdict: A useless machine.

Atari 600XL

Virtually identical to the 800XL. 16K RAM, case is less deep. Slightly cheaper,the 600XL appeared a few months before the 800XL. See the 800XL description for more information.

Atari 800XL

Specs: Real keyboard, 64K RAM (not sure if all is usable, is the OS copied to RAM?), 16K ROM (OS + Basic), 1.79MHz 6502 (why this weird speed? I've seen it with various Z80 machine too: 3.58 MHz (factor 2); looks like being related to video clock speed so that no special delay circuitry is necessary to handle CPU/graphics chip RAM access clashes).

Good:

Bad:

Verdict: Appeared too late. It's specifications were just about ok at the end of 1983, but that's all. It was basically an already 4 year old design, showing its age, and soon being completely overtaken. So, all in all: superfluous.

Enterprise 128

Specs: 128K RAM, 48K ROM, 4MHz Z80 CPU, membrane keyboard with moving keys.

fill in...

Good:

Bad:

Verdict: Sounded good at the end of 1983, actually useless at the end of 1984/beginning of 1985.

Other machines I will not dive deeply into for the reasons given:

Apple 2

The ridiculously high price makes any positive points just about irrelevant, but I'll name one: The case is good for expansion, with room for internal cards just as with PCs.

Later machines, introduced 1985-1986

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