Re: A500 [was : AmigaOne X5000]

[Frank Wille <frank.wille%wendik.de@localhost>]

On Tue, 21 Mar 2017 11:14:23 +0100
goon <goon%yellowcouch.org@localhost> wrote:

> > > No, it's for the A500 from 87 :-) There's just support ending in obsd 3.2
> > > for the A1200 and up.
> > 
> > Without an MMU? IIRC we already support A500 with a suitable CPU upgrade.
> > 
> 
> I read some history sites about the A500, I have on with 1Mb RAM.

And certainly a 7 MHz 68000 CPU...


> The thing
> is I downloaded srcsys and am looking at the code but it is somewhat unclear
> to me where the differences lie in between the A500 and up until A2000 as
> these are newer supported machines.

The A2000 is basically the same hardware as the A500, but it is more
expandable and adds a couple of Zorro II slots in a big deskstop case.

Both have only a 68000 and no MMU in their base configuration.


> Do you know where to find good datasheets for it ?

Amigas are, unlike modern hardware, very good documented. You want the
Hardware Reference Manual, e.g. from here:
  https://computerarchive.org/files/comp/books/amiga/Amiga_Hardware_Reference_Manual_(1986).pdf

Maybe you also find the Technical Reference Manual interesting:
  http://classiccomputers.info/down/Commodore/Amiga/Amiga_A500_A2000_Technical_Reference%20Manual_1987.pdf


> The kernel can probably be improved by smaller memory footprints FWIW. 

Yes, an (optional) smaller memory footprint is indeed desirable for many
of the older hardware supported by NetBSD.

But before you spend too much time on it:
NetBSD will NOT work without a MMU, even if you manage to shrink the kernel.
You need to equip your Amiga with at least 68020/68851 or 68030 CPUs.


(Moving this to port-amiga, as the A500-thread has nothing to do with
PowerPC anymore.)

-- 
Frank Wille <frank.wille%wendik.de@localhost>