Dreaming of the 68000
In 1985, the Atari ST was launched just before the Commodore Amiga. Like the Apple Macintosh, they both used the 68000 microprocessor, and were both classed as 16-bit machines. But they were cheaper than the Mac, and also offered colour.
The name ST means Sixteen/Thirty-two. This refers to the fact that the 68000 chip has a 16-bit data bus, but is 32-bit internally.
With the ST being cheaper than the Amiga, I imagined that it might be the one which I’d eventually own, as a successor to my Commodore 64. Despite it lacking the Amiga’s advanced custom chips for sound and graphics, it still had a lot to offer, compared to even the best 8-bit computers.
It’s hard not to compare the ST and the Amiga, but the original Amiga 1000, with its separate keyboard, was really in a higher price category. Things started to change in 1987, when Commodore released the cheaper Amiga 500 model — that’s when the rivalry really began. In some ways, the ST vs Amiga arguments reminded me of the rivalry between the Sinclair ZX Spectrum, Commodore 64, BBC Micro and Oric 1, from a few years earlier.
When comparing the Amiga 500 and Atari ST, it really does look like Commodore copied the ST’s form factor. The two machines were of similar size and shape. Both had a built-in keyboard and 3.5″ floppy disk drive. And they were both supplied with a mouse. The two machines also shipped with either 512 KB or 1 MB of RAM. However, the Apple IIc had a similar form factor in 1984 — one year before the ST.
At this point, I should point out that I bought an Amiga 500, in 1987. But I’ve tried not to be too biased against the ST…
GUI and Operating System
Atari opted to use Digital Research’s GEM as the graphical user interface for the ST. Although GEM got the job done, I think it made the ST seem somewhat dull in comparison to the Amiga, which had its own Intuition GUI. The ST also had a simpler underlying operating system. Unlike the Amiga, it didn’t support preemptive multitasking.
As an Amiga owner, it always niggled me that the ST had its 68000 CPU clocked at 8 MHz, which was about 13% faster than the original Amiga.
That meant the Amiga simply couldn’t win when it came to CPU-intensive tasks. But the Amiga’s custom chips usually gave it the edge when it came to graphics and sound — especially if the software was well-written.
For graphics modes, the ST supported 320 x 200 in 16 colours, or 640 x 200 in 16 colours, from a palette of 512 colours. It also had a high resolution 640 x 400 monochrome mode, if a suitable monitor was available.
The Amiga offered more graphics modes, and supported up to 32 colours from a palette of 4096 colours. It also had a special mode which allowed all 4096 colours to be displayed at once, with certain limitations.
The Amiga could only match the ST’s high resolution mode when using interlacing. This resulted in flicker, unless a special ‘flicker fixer’ add-on was used. However, the Amiga did support up to 16 colours in that mode, rather than just monochrome.
One of the Amiga’s custom chips had a blitter, which enabled fast line drawing and image manipulation, with minimal help from the CPU. The original ST did not have a blitter, and — like the Apple Macintosh — it had to use the 68000 instead, resulting in slower graphics performance.
Unfortunately, Atari only gave the ST an fairly simple 3-voice sound generator chip, making it similar to many 8-bit computers in sound capability. The Amiga was much more advanced, with its custom sound chip capable of playing 4 channels of 8-bit sampled sound.
The ST had built-in MIDI ports, which made it popular with musicians who wanted to sequence music keyboards and synthesizers.
Because I chose the Amiga instead, I needed to use an external add-on to do those things.
Following the initial 520 ST and 1040 ST models, Atari released some more advanced models, such as the Mega ST. This had more RAM, and a blitter chip for faster graphics. There was also a Mega STE, which had a faster 16 MHz processor.
The 520 STE and 1040 STE models also had a blitter chip, as well as a larger palette of 4096 colours, to match the Amiga.
I don’t regret choosing the Amiga instead of the ST — it was the right choice for me at the time. But looking back now, I think I judged the ST rather harshly in the past. It seems that the ST was also a very capable and deservedly popular machine.
Do you have memories of using the Atari ST?
Share your thoughts in the comments section below.
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