[rescue] newest rescue

[Romain Dolbeau]

2016-02-03 19:12 GMT+01:00 John Hudak <jjhudak at gmail.com>:

> Can you elaborate on this a bit? (not to hijack this thread). You are
> saying to get full 32 bit address space I need to get the 32bit enabled
> ROM?  I thought the address li nes were not even there?
> Can one still get NetBSD for the SE30?
>

The lines are here, the 68030 is fully 32 bits. However, the regular 68000
wasn't, it only used the low 24 bits of each address. So in the original
(Lisa?/)Mac operating systems, Apple used the upper 8 bits to store some
pointer metadata. As soon as you wanted to use the full 32 bits address
space, that didn't work so well... They had spec'ed some accessors
functions for those metadata, so any compliant code worked just fine, but
some of the ROMs wasn't so-called "32-bits clean": they didn't use the
accessors but used direct access. Those had to be replaced by software
patch or ROM updates to become "32-bits clean" and let you run the newer
OSes (OS 8 ? perhaps some 7, can't remember).

No idea how it really impacts alternative OSes, but I would suspect not at
all since they don't use the functions in the ROM.

Some version of NetBSD definitely ran on the SE/30, and pretty much any
other 680[234]0-based macs, as long as they had an MMU (i.e. all 30/40 and
the II with the optional 68851 originally intended for AUX).

And I'm really jealous of the 3/470, like everyone. I have a 4/330, and I
love those big, ungainly, *noisy* beasts of a system. Lucky you.

Cordially,

-- 
Romain Dolbeau