LC 580 & 24-bit Addressing

[Mac128]

Anyone know what is the reason that the 580 cannot use 24-bit addressing. Is it in the ROM? Or is it some other kind of hardware restriction?

 

[porter]

Anyone know what is the reason that the 580 cannot use 24-bit addressing.

This just lists it as 32bit.

http://lowendmac.com/500/performa-580.html

Why do you need 24bit? Really that should be for trying to run old System 6 software, eg non-32bit clean. You want to run dirty software?

 

[equill]

Bittitude, as opposed to beatitude, is a function of processor and System. 68000 machines were 24-bit as a make-do. 68030 machines were given optional 32-bit capability at first in System 7, and then obligatory 32-bit operation. Some 68000 machines can run System 7 (up to 7.5?), but seldom with distinction. What is the attraction, apart from use of a IIe card?

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[defor]

as the 580 is a 630 with a crt attached shoehorned into a 520's case, I'd look towards why the 630 won't do 24-bit, and I'd wager it is because iirc, the oldest system shipping with the 630 was 7.5

 

[LCGuy]

Actually, it was 7.1.1.

 

[defor]

did it really? guess the one I first used might have been a late version because i definitely remember it coming with 7.5

 

[LCGuy]

The very early 630's came with either 7.1.1 or 7.1.2, I'd imagine that after 7.5 came out the 630 then got 7.5.

 

[Charlieman]

Has anyone else tried to create a System Enabler? I tried to make one for the Pippin years ago to run a G3 accelerator and failed.

In theory, you should be able to take resources from a supported OS and plug them into an Enabler template. The template will load the resources and you should be able to run on an earlier OS. Unfortunately Apple treated the Enabler as proprietary and there are few sources of information. Any contributions or sample code?