Talk:Motorola 68020

It may be worth comparing the transition from 16-bit to 32-bit APIs and programming models in the Motorola/Macintosh world versus the Intel/Windows world.

In the Intel/Windows world, the transition entailed the creation of all-new 32-bit versions of the Windows APIs, with a new "flat" memory model in place of the old "segmented" memory model. This transition took most of the 1990s to happen.

In the Motorola/Macintosh world, on the other hand, since the original 68000 was designed essentially as a cut-down 32-bit processor to begin with, the transition to the 32-bit 68020 and later processors was really just a matter of filling in gaps. Addresses were always 32 bits--albeit since programmers knew the 68000 processor ignored the top 8 bits, they had got into the habit of storing other information there, and so there was a transition as programmers had to rid themselves of this habit and make their software "32-bit clean". But this did not involve the creation of any major new APIs, let alone a new memory model, and 32-bit-clean software could continue to run on older machines. The transition was essentially complete by 1993.

Ldo 10:16, 12 Sep 2003 (UTC)

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In which year did the 68020 appear ?

PS: There was no 16-bit API on the macs, AFAIK.

--213.253.102.145 17:27, 6 September 2005 (UTC)

I believe it was 1984 - http://www.cpu-world.com/CPUs/68020/ agrees. Mdwh 02:21, 16 January 2006 (UTC)