Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bbn!ulowell!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: amiga 2500UX
Message-ID: <5870@cbmvax.UUCP>
Date: 31 Jan 89 23:44:29 GMT
References: <14054@cup.portal.com>
Organization: Commodore Technology, West Chester, PA
Lines: 49

in article <14054@cup.portal.com>, Bruce_Eric_Bowers@cup.portal.com says:

> In article <5827@cbmvax.UUCP>, daveh@cbmvax.UUCP (Dave Haynie) says:

>>                              No matter the preset, holding down both
>>mouse buttons at boot time will get you a menu that lets you select the
>>Amiga OS controlled by either the 68020 or the 68000, or UNIX if you have
>>it on your hard disk.

> Is this true of any 2500? Does the 68000 still run at 7 MHz?

Yes, and yes.

> I've been very impressed with the 2500, and I'm saving my pennies to buy
> one. One of the things that has concerned me was the possibility that
> some software would not work on a 2500, due to either the slightly 
> different instruction set of the 68020 or to the faster clock speed.

There are a few programs that don't run; the vast majority do run.  You can
turn the 68000 on at boot time, as described, to run any non-conformant
programs.  I've found a better solution, though.  First, if it's a commercial
program, see if there's a corrected version from the vendor; same with PD
programs, though there's probably less of a chance here since most of the
PD stuff I've encountered seems to be written in HLLs, which don't as a rule
produce incorrect code (some very old one did, but far as I know, not any
longer).  If the company doesn't support the program, the best solution is
to dump it, perhaps flame loudly enough to attract the attention of any
other potential buyers, and then get something that works.  Because chances
are, if they won't fix it to run correctly with the 68020 (all correct 1.2
and 1.3 programs work with the 68020), they probably won't fix any nasty
bugs you find now, or other incompatibilites with future operating systems.

> If I can choose to run the 2500 on a 7 Mhz 68000, then I'm no longer
> concerned. I haven't heard of any incompatibility problems with the 2500,
> but then I haven't heard of many people that have them yet. Anyone with
> a 2500 care to comment?

And while the current 2500 system, being of course based on the A2000+A2620,
let you drop back to the 68000, future 32 bit machines won't carry around 
the 68000.  The main reason I put the drop-back-to-68000 mode in the A2620
wasn't really to support broken programs, but to allow folks who develop
on the 68020 a real easy way to test their applications on a 68000 machine.
Sure beats having to buy an extra A500, or having to yank the A2620.

> Thanks!
-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
              Amiga -- It's not just a job, it's an obsession