Linked by Hadrien Grasland on Fri 30th Dec 2011 08:24 UTC
Hardware, Embedded Systems In the world of alternative OS development, portability across multiple architectures is a challenging goal. Sometimes, it may be intrinsically hard to come up with hardware abstractions that work well everywhere, but many times the core problem is one of missing information. Here, I aim at learning more about the way non-x86 architectures deal with CPU IO ports, and in particular how they prevent user-mode software from accessing them.
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RE[2]: Moto 68k
by ricegf on Fri 30th Dec 2011 17:06 UTC in reply to "RE: Moto 68k"
Member since:

Exactly. The Amiga (and its spiritual predecessor, the beloved Atari 800) used custom chips to allow the processor to concentrate on processing rather than managing I/O.

Unfortunately, it also made upgrades to those architectures very expensive compared to commodity IBM PC designs.

There's no free lunch (to coin a phrase), but in the early years, the Atari / Amiga computers ran rings around the designs that finally conquered the market.

(An old codger reminisces - sorry 'bout that...)

Reply Parent Score: 3

RE[3]: Moto 68k
by leech on Fri 30th Dec 2011 18:48 in reply to "RE[2]: Moto 68k"
leech Member since:

Ha, no worries. Loved my Atari 800XL. I still have it, but the last time I fired it up, the RF modulator was only sending black and white signals to the screen. Not sure if it was the cable, or something internal, but I did at one point drop it down my stairs...

Fortunately at one point in time I also managed to acquire an Atari 130XE.

Speaking of reminiscing.... at one point in time we had somehow managed to get strawberry jam on a floppy disk.

We washed it, and some of the stuff started working. Washed it two more times and all of it was working again. Those 5 1/4" floppies were hard to destroy!

Only at a much later date did I realize that Jay Miner created both the Atari 8-bits and the Amiga. Unfortunately, as most people I'm sure did, I upgraded to an Atari ST instead of the Amiga. Even though the C64 had it's share of bugs, the owners of those upgraded to the superior Amiga. The makers being opposite.

Now I'm rambling... cheers!

Reply Parent Score: 3

RE[4]: Moto 68k
by zima on Fri 6th Jan 2012 23:59 in reply to "RE[3]: Moto 68k"
zima Member since:

At the risk of rekindling one long-forgotten Holy War ;) - 8bit Ataris and C64 were fairly comparable all around (the former also having its share of bugs) ...C64 somewhat better in some interesting areas (kinda discussed here, support chips and such), which made it the machine of the demoscene, one which essentially started it all. Seemingly much more long-lived, too.

Atari 16bit being what they were... overall it was probably better to be on the Commodore side of things throughout, unless maybe for MIDI (IIRC) of ST. At the least, my buddy who had both (8bit) machines, opted to get rid of small Atari much sooner than C64 (and BTW, most of the world didn't standardise on floppies in that generation, so any flaws of them on C64 were irrelevant; OTOH, later 8bit Atari models were legendarily... neurotic, when loading a game; probably also a case of different worlds, different "ecosystems" already )

Edited 2012-01-07 00:19 UTC

Reply Parent Score: 2

RE[3]: Moto 68k
by BushLin on Sat 31st Dec 2011 13:24 in reply to "RE[2]: Moto 68k"
BushLin Member since:

I love looking back at the early Amiga days and wonder what might have been, wasn't going to reply but I'm really pedantic:

"to coin a phrase" means to invent a phrase, if it's then followed by a cliché I find it really jarring... enough to write a reply to someone I don't know, in the hope they don't do it again.

Reply Parent Score: 1

RE[4]: Moto 68k
by ricegf on Sat 31st Dec 2011 23:46 in reply to "RE[3]: Moto 68k"
ricegf Member since:

When I list a cliché followed by "(to coin a phrase)", I'm making a mildly humorous reference to the fact that it is a cliché - not claiming that I actually invented the phrase! It's a little like saying "the Internet (as invented by Al Gore)..." - it's humor by farcical excess.

And yes, I'll do it again, as you're the first person in my 22 years of Internet posts to have admitted missing the intended humor. ;-)

Edited 2011-12-31 23:47 UTC

Reply Parent Score: 2

RE[3]: Moto 68k
by axilmar on Tue 3rd Jan 2012 11:55 in reply to "RE[2]: Moto 68k"
axilmar Member since:

The Atari series (XT/XL/ST) did not have the same mechanisms as the Amiga regarding DMA, and therefore things like playing a game on them while something loaded from floppy was not really possible to the same extent as the Amiga.

The Amiga was not more expensive than IBM compatibles. In fact, it was cheaper. An Amiga 600 would set you back for around 1000 dollars, whereas a PC with equivalent performance (think about the early days of 386 with VGA cards), would cost a lot more.

Reply Parent Score: 2

RE[4]: Moto 68k
by zima on Fri 6th Jan 2012 23:55 in reply to "RE[3]: Moto 68k"
zima Member since:

Amiga 600 - hence heyday in 1993. An inexpensive machine, to be sure (much less expensive than you portray it; closer to what would be, after exchange, 200 dollars or so - of course without HDD and monitor, however a. they were hardly available anywhere in the first place b. what was almost always just a "gaming computer" didn't really need them) ...but essentially identical to Amiga 500, over half a decade old. As was 386, but even those didn't exactly stand still (I used some "surplus" late 386 in 97, it was quite nice with Win 3.11)

Which was more the point, I think - the tightly integrated architecture made the upgrades of the architecture (manufacturer side) expensive - engineering, implementation, it was almost either all or nothing (worse: with the dynamics of "installed base" very console-like ...but lacking appropriate in such case business model; Commodore essentially repeating US video game crash of the early 80s; coincidentally, the Amiga was supposed to be a console initially). Sure, that tight integration of hardware made Amiga nice & speedy for some time, but ultimately it largely limited its progress, arguably contributed to its demise.

Yes, there was 1200 - but not so affordable any more and... not really that much better, hardly compelling (most of the software people were interested in, ran happily on 500/600).

Edited 2012-01-07 00:12 UTC

Reply Parent Score: 2