Linked by Kroc on Thu 24th Aug 2006 20:26 UTC
OSNews, Generic OSes GEOS managed to offer nearly all the functionality of the original Mac in a 1 MHz computer with 64 Kilobytes of RAM. It wasn't an OS written to run on a generic x86 chip on a moving hardware platform. It was written using immense knowledge of the hardware and the tricks one could use to maximise speed. Note: After a small break, here is another one of the articles for the Alternative OS contest.
E-mail Print r 14   · Read More · 45 Comment(s)
Thread beginning with comment 155719
To view parent comment, click here.
To read all comments associated with this story, please click here.
Member since:

If you are going to nit-pick, please nit-pick with more accuracy. ;-)

> also did have some instructions that would work on
> 32 bit data

The 68000 was fully 32-bit internally. So, it wasn't just 'some instructions' that operated on 32-bit data, but most instructions since its general-purpose registers were all 32-bit.

Yes. It did have a 16-bit data bus and a 24-bit address range (the address bus was actually 23 bits wide - it took some extra magic to access odd addresses). Thus it was usually billed as a 16/32-bit CPU.

Reply Parent Score: 1

evilrich Member since:

> The 68000 was fully 32-bit internally.

To nit-pick myself, that's not quite true, either. ;-)

The ISA was 32-bit, but the 68000 was mostly 16-bit internally.

Reply Parent Score: 1

The 68000...
by Kochise on Fri 25th Aug 2006 07:32 in reply to "RE[2]: Slight nit-pick for technical accuracy..."
Kochise Member since:

The 68000 have 8 *TRUE* 32 bits data registers, not extended registers like on x86. I'm an assembler coder for various CPU, and the 68000 is really a good piece of hardware !

The 68000 have a 24 bits address bus which allows addressing 16 MB flat memory (where x86 could only access 640 KB, or 1 MB if A20 used). The data bus is 16 bits, thus reading/writing a 32 bits data needs two access.

With the 68020 (the *FIRST* full 32 bits CPU ever), the address bus *AND* the data bus are spread to full 32 bits, both internaly AND externaly...

ONLY after that Intel followed with the 386 that was 32 bits as well...


Reply Parent Score: 1