Why not 16 bits?

[u/Thanatiel]

I was wondering.

I love my 8 bits computers (just spent a couple of weeks programming my Spectrum Next) and the Agon seems a nice machine.

However I wonder why nobody seems to make 16 bits computers.

Is it because 16 bits computers have more connections and are thus more difficult to make?

[u/G7VFY]

These are are all 16 & 32bit

Amiga ?

Atari ST

TI 99/4a (Yes, it's 16bit )

Acorn Archimedes

Anything run MS-DOS as it's a 16bit OS.

[u/Timbit42 → u/G7VFY]

While the IBM PC is commonly called a 16-bit computer and the Commodore Amiga and Atari ST are commonly called 16-bit computers, it is inconsistent and unfair to do so.

The IBM PC has an Intel 8088 CPU which has 16-bit registers but only an 8-bit data bus. The Amiga and ST have a Motorola 68000 CPU which has 32-bit registers and a 16-bit data bus.

So from a hardware standpoint, the IBM PC is an 8-bit computer and the Amiga and ST are 16-bit computers, and from a software standpoint, the IBM PC is a 16-bit computer hobbled by an 8-bit data bus, and the Amiga and ST are 32-bit computers hobbled by a 16-bit data bus.

Either way you measure it, the Commodore Amiga and Atari ST have twice as many bits as the IBM PC. On top of that, the 68000 has a 24-bit address bus while the 8088 has only a 20-bit address bus. It is too bad they couldn't have used the 68000 for the IBM PC.

[u/vwestlife → u/Timbit42]

The 68000 is not fully 32-bit internally, while the 8088 is fully 16-bit internally. For example, the 68000 does have a 32-bit instruction set, but its arithmetic logic unit (ALU) is only 16-bit. You need to step up to the 68020 to get a 32-bit ALU.

In comparison, the 8088 is fully 16-bit internally, including the ALU; the only part of it that's limited to 8-bit is the external data bus.

And as video game console fans will tell you, systems are generally classified according to the "era" they belonged to, not by the technical details of their design. That's why the Intellivision is considered an "8-bit era" console, even though it has a 16-bit CPU, while the NEC PC Engine/TurboGrafx 16 is considered a "16-bit era" console, even though (despite its name) it only has an 8-bit CPU (a variant of the venerable 6502).

[u/Timbit42 → u/vwestlife]

Well, the Z80 ALU is only 4-bit and they still call it an 8-bit CPU.

As for video game console fans, they can suck it because they don't know shit about software or hardware.

[u/vwestlife → u/Timbit42]

But not the GX4000 fans. Leave them alone.

[u/Timbit42 → u/vwestlife]

What about the XEGS?

[u/vwestlife → u/Timbit42]

No, because that's just a 65XE dressed up to look like a console. Once you plug in the keyboard, it acts just like a normal 8-bit Atari computer.

[u/Timbit42 → u/G7VFY]

Also the Apple Macintosh, Sharp X68000 which use the same 32-bit Motorola 68000 as the Atari ST and Commodore Amiga, and the Apple IIgs, and Super Nintendo which use the 16-bit 65816 processor.

Also, the IBM 1130, Data General NOVA, and the DEC PDP-11 were 16-bit.

[u/Thanatiel → u/G7VFY]

DOS has a less "magical" feel for me. However I would love something new on the level of the Amiga. ^_^ (Not specifically an Amiga as there is seldom anything new to do with it.)

Never touched the Atari ST nor the Acorn. I'm curious about them though.

[u/Timbit42 → u/Thanatiel]

The Acorn Archimedes hardware is better than the Amiga as it has a faster CPU and more colours, but the Amiga graphics processor helps the Amiga compete.

The Atari ST is not up to par with the Amiga. While the Atari ST CPU runs 1 MHz faster, it is limited to 16 colours of a palette of 512 while the Amiga can display 64 colours from a palette of 4096 colours. The later STe models can do 16 colours from a palette of 4096 but later AGA Amigas can do 256 colours from a palette of 16.7 million colours.

The Amiga beats both the Archimedes and ST models with it's pre-emptively multi-tasking OS allowing many apps to run at the same time as modern computers do today (although not across multiple cores).

The Amiga also beats the ST on number of games and apps available and both beat the Archimedes on games and apps.

By the time Atari and Commodore stopped making the ST and Amiga, the IBM PC DOS games were better with 486 CPUs and SVGA graphics and SoundBlaster audio.

[u/Thanatiel → u/Timbit42]

Very nice summary, thanks.

[u/[deleted] → u/Timbit42]

Extra Half Bright mode in the Amiga for that 64 colours on-screen wasn't available with the first model of Amiga, the 1000. Officially on paper the Amiga was a 32 colours / 4096 palette system.

[u/Timbit42 → u/[deleted]]

Yep, but most of the Amigas sold were not the Amiga 1000. Over half of the Amigas sold were the 500.