Chris Ludwig Interview- Conducted by Amiga News, 1995
An interview with Amiga software engineer Chris Ludwig at the World
of Amiga Show in London on December 11, two days after he and the
other members of the surviving Amiga development team finally left
AN: You're probably the last person to work for what was once
called Commodore Business Machines?
CL: Actually there's one person still working there, that Jeff
Frank, head of hardware engineering and his job at the moment is to
liquidate any of the hardware that's left at Norristown. That
may have changed since Friday. Friday was the last day
at Commodore for myself and for a lot of other people as
well. There were 16 of us, engineering staff.
AN: You were continuing work on a new system?
CL: There was not a lot of development going on, mainly because
the resource wasn't there, there was not a lot of money to be
spent. We didn't have quite the number of people we
needed. There were some software ideas being toyed with,
there were some hardware ideas being toyed with, but there was no
steady development goal...
AN: We were here last month at the Future Entertainment Show and
we were told that the HP Risc chip had been chosen as the basis for
future Amiga development.
CL: That is correct.
AN: Mr. Pleasance told us this morning that the fact that work
has now stopped means that some new agreement will have to be drawn
up with HP in order to re-start development.
CL: Yes, but having said that, the deal that we had with HP was
a solid one, and I don't think there going to be a problem
there. They've got every reason in the world to want that to
go through with whoever continues the Amiga.
AN: Was Lew Eggebrecht still working with you?
CL: Towards the very end he wasn't there full time, he was just
consulting to us, but when we needed him we could just call
AN: He knows the HP architecture really well?
CL: Somewhat well. We did have a resident expert, Dr
Edward Heppler, the guy who designed the RISC 3D system, and he was
there to the end. And he's committed to it so I'm sure that
if something happened we'd get him back on board.
AN: Did the Amiga design team take that decision to go to HP
RISC or was it a Commodore decision?
CL: It was a Commodore decision. We spent a lot of time
looking at available processors and trying to decide which one best
met the needs that we had in mind for the future of the
platform. We chose it based on a number of different
concerns: - first of all, compatibility with existing
products. HP, because of their having bought out Apollo
(constructor de stations graphics) have an interest that their
processor is 68000-compatible, so there's a 68000 compatible
emulation mode for the PA-RISC
AN: Does that exist already?
CL: Yes, that already.
AN: Is that emulation in hardware?
CL: Its both, basically. The instruction architecture is
similar to 68000 in many ways and there's some software emulation
tricks that can be done as well, so between those two pieces it
makes migrating easy. It doesn't guarantee compatibility,
it's not like Power PC where you have compatibility that's
basically out-of-the-box, they haven't got that finished and I
don't know that they will, but it makes the migration path much
shorter, there's a lot less that has to be done in re-coding.
AN: HP is doing that work themselves?
CL: That's correct.
AN: So that will make it a lot easier to create something
resembling AmigaDOS portable onto the HP RISC?
CL: Exactly. That was one of the principal reasons for
choosing the HP chip. Other reasons were we wanted a chip
that would allow us a greater degree of control in implementing our
own ideas for the 3D half of the work.. For example you
can go and buy, for PowerPC for example, if you want to be a
PowerPC hardware OEM (Ed: ,original equipment manufacturer, ou
autrement dit un fabricant qui prends un produit de base d'un autre
fabricant et l'utilise pour crieer un autre produit) the
PowerPC core, which is a little square portion of the die and then
they give you the L-shape around the rest of the die in order to
add in your hardware. That's how it basically works if you
want to have a PowerPC-based chip of your own.
AN: But no PowerPC user has yet done that, they're all using the
basic chip as it comes.
CL: Yes, exactly. It's been done with other chips.
But we wanted to have our own die, our own semi-conductor work on
the same die as the HP-RISC. With the PA-RISC, unlike the
PowerPC, we're actually allowed to have a free rein over the whole
die, so that we can take a HP-RISC core and basically put in pieces
that we want, take out pieces that we don't want,
add instructions, which is very important for us. We've had a lot
of work spent on designing new instructions which allow us to have
really fantastic 3D performance, and the PowerPC wouldn't have let
us do that, the HP stuff does.
AN: So you're creating a custom HP-RISC for the Amiga.
CL: Exactly, that was the plan, we're basically creating a
custom PA-RISC chip based on the PA-150, the latest one, that would
allow us to have really fantastic performance.
AN: How far have you got with that work?
CL: We've got software simulations of the chipset running.
We did software simulations of some of the four pieces and they
worked, so we're satisfied that...
AN: Would those four chips come into one at a later stage?
CL: You mean the Amiga chips? Yes. Essentially, in
that one core we'd be taking the planned sound enhancements for AAA
as well as all the graphics enhancements that we've designed for
the RISC release and obviously the CPU port there as well.
You'd still need a digital/analog converter at the end that does
the colour tables for the back end of the video, but those are
standard parts, it's not something that we have to design
ourselves, and you've basically got a one-chip solution, that's
Another reason for choosing the PA-RISC was that the PA-RISC is
designed around allowing you to have a multi-processer system, with
other processors acting as enabling processors. So that for
example we could have a one-chip solution which would be very low
cost for games systems for example, that was just our version of
the custom PA-RISC, but we could
have higher-end systems where our chip is actually just a
sub-processer that's doing graphics work and another PA-RISC is
doing the! major computation, so you've now doubled the
through-put of the system and you still get all of the graphics
performance that you have but your competition haven't on the
PA-RISC chip, so you've got really tremendous performance.
And you can scale that architecture to get quite high-end
AN: Does that go as far as controlling transputers?
CL: It's not quite the same as transputers, it's not infinitely
scalable. Transputers obviously give you a lot more scalability in
that direction. But its a more tight integration as well.
From a software perspective it's easier to code for because you're
basically spawning off the graphics sub-tasks to the other chip,
it's basically designing it as if you were working with a one-chip
AN: So how much time would be needed to finish it.
CL: We're looking at 18 to 20 months from inception. When
somebody gets the deal and says 'Go forward' and the money's there
it'll take about 18 months. It's the whole chip design that
needs to be done and software support has to be done... it'll
take some time.
AN: And that's not variable depending on the resources that you
put behind it?
CL: Well of course it is, but not to a great extent.
That's probably the fastest it could be done. But the amount
of resources required isn't tremendously huge compared to what
we've had in the past. It's certainly a do-able thing.
AN: Apparently Windows NT would run on this.
CL: Sure, Windows NT runs on PA-RISC and we're not taking
anything away that would prevent that.
AN: So tell us what AmigaDos would look like on such a
machine. In what way would it be able to retain the
AmigaDos that we know.
CL: The plan is simply to port AmigaDos to the chip. So
Exec will be ported, graphics will be ported, Intuition will be
ported, all portions of AmigaDos that currently exist will be
ported, the idea being that the system will be wholly an Amiga,
with the capability of running Windows NT as well. Because
it's a PA-RISC there will already be native compiled versions of
NT. You're basically talking about a box that can run two
OS's. Three if you count HP's system.
AN: The new AmigaDos would not be compatible with existing
CL: That's correct, people would have to re-compile their
existing software. But, again, because of the chips degree of
compatibility with the 68000 line that shouldn't be a gargantuan
effort. It should be about as straightforward as it is for
Apple people to recompile in order to get their current 68000-based
applications to run on PowerPC.
AN: Is all this something that can realistically be done now if
someone ends up buying the Amiga?
CL: Absolutely. It's a matter of ensuring that there's
some vision at the top of the company in order to let something
like this go through. Commodore has too often in the past been in
the situation of having designed very cool products which just at
the very end of the life cycle after we've spent all the money on
them don't actually make it to market because the people at the top
have a lack of vision and when they see the finished product say
"Oh no, they wouldn't wanna buy that." But I don't
think we'll see that with the potential buyers.
AN: This work you've been doing is one of the major assets of
Commodore and we suppose that's why the liquidator kept it
going. That means that anybody who buys Commodore will be
able to continue this project.
CL: Absolutely. It really depends on how the buy-out
happens. Anyone who's buying the whole company will get the
rights to build this computer. But there's been talk that the
liquidator may be deciding to sell off the company piecemeal which
would mean that if someone wanted to pick up just this technology
they could come in with a smaller figure than the full
value of the company, and somebody else could buy the right to use
the names Amiga, etc.
AN: Do you think that people who have been working on this will
be able to come back if the sale happens fairly quickly?
CL: If it happens fairly quickly I feel personally quite certain
that people who were involved would be interested in coming
back. It depends on how long it takes. In six months
from now if nothing's happened I'm sure they'll all have jobs and
they'll probably be quite happy with them. Its maybe not going to
be the same spark that we had with Commodore, but
you never know. If the money's good, you've got wives and
AN: Mr. Amor said on Portal the other day that he wasn't sure
which RISC chip to go for. He said the Mac and the PC were
pulling towards the PowerPC, but talks had already gone on with
HP. He didn't seem to be firmly fixed on this idea of an
CL: The truth is that he's had very little contact with the
engineering staff. He's been around once or twice but beyond
that things have been in a vacuum.
AN: You've had more contact with other teams?
CL: Yes, definitely. We've had more contact with teams
that have gone away now. At one point Samsung were a
CL: Yes, but that was a long time ago.
AN: All these people are apparently going to have another
possibility of making a last bid.
CL: Sure. I think that having got rid of the engineers and
Christmas obviously being dead now, it means the value of the
company has probably been reduced quite a bit, and people who lost
interest before may be more interested now that the price has gone
AN: We heard some months ago that Samsung were not really
interested in continuing the Amiga computer line.
CL: It's difficult to say. They were obviously interested
in the engineering know-how that we had and in a number of the
hardware designs that we had. Whether or not they were
interested in continuing the Amiga as a product line is difficult
AN: Do you have a personal favourite buyer? Who has most
impressed you? I'll try not to let anybody hear your answer
(AmigaNews Ed: David Pleasance was in the same room during part of
this interview but was talking with Jim Drew and other people).
CL: All I can really say is, whoever takes over the company I
hope they have a driving instinct and vision to bring forth the
best that the platform has to offer. I worry that people may
have a short-term view of what to do with the platform, that some
of the buyers will have a potential of just wanting to do a kind of
smash and grab operation.
AN: You think there are some like that?
CL: I think so.
AN: Do you think there are some serious ones as well?
CL: Yes there are some serious ones.
AN: Would you include CEI and the English Commodore team?
AN: You're not very sure.
CL: It's difficult to say. I think that the UK team have a
real clear idea of where they want to go, and that's very
AN: The Amiga has done very well in the sense of its
technological specialties. How may of those would you be
keeping with this new system, like draw-down screens, video
compatibility, this sort of thing.
CL: Obviously the chip-set's gotta be video compatible.
One of the major reasons for making sure that we have a low-end
version of the chipset is that it would be usable in video games,
set-top boxes, and low cost multimedia presentation devices like a
cheap television set-top bo, so it's gotta have video
compatibility. The blitter portion of the engine will retain
peroccupatibility with current blitter stuff.
AN: Scrolling the way we've got it now?
CL: Yeah, yeah, we'll have scrolling. A number of the
current video modes will be available or at least emulated, and
then the the new video modes I think you going to be surprised
with. There's some great modes.
CL: We're probably going to toss sprites altogether. If
you look at how games programmers write games today, very few of
them are actually using sprites any longer. They use just one
sprite for the main character and they toss out the rest; just
because the overhead for sprites, while it's minimal, it's so much
easier these days to, especially if you're porting to PC
compatibles, to not have to deal with the sprite issue. It
just makes more sense to dispose with it altogether and use the
real estate that we gain to enhance the 3D abilities.
AN: Is the AAA chipset definitely out?
CL: I don't know that it's definitely out. Dave (Haynie)
spent a lot of time getting a system out that would, at least from
a hardware perspective, work I think the problem with
it is that from a feature-set standpoint it really doesn't buy us
enough in the short-term to be useful in the short-term and in the
long-term we're better off trying to leapfrog the feature-set
entirely so that we have something new and innovative, and that's
why we focused on the RISC-3D stuff.
AN: The specifications of the AAA seemed pretty impressive from
the average Amiga user's point of view, and now you're talking
about leapfrogging. Is the Custom RISC really that much
better than AAA?
CL: Oh yes, definitely. From what we know reading IEEE
magazine and playing with them our system will beat the pants off a
Saturn (Sega's coming console). We've designed it around
being a really fantastic system, exercising the best of the
resources that Commodore's always had, basically designing our own
chips rather than going out to someone else and just using an
off-the-shelf chip. We've got some really good stuff
AN: So you can envisage having a wide range of Amiga products,
from the games player to the professional user, in the real
tradition of the Amiga which has been so hard to market...
CL: Yes it has been hard to market. That's it. It's
one of our assets, and getting rid of it by just concentrating on
one end or the other would be a mistake.
AN: So you've got built in there all sorts of texture mapping
and other capabilities?
CL: Yes. Basically the blitter has grown features that
allow it to do texture mapping, that allow it to do shading like
the new consoles, but faster and with higher quality video modes,
so that we've got a greater resolution than the consoles have,
because at the high end we're going to need that resolution.
We've got completely programmable pixel rates, as you know that's
basically a feature that started with AA, that AAA grew some, and
this basically continues that growth path so that we'll be able
to do a large number of graphic modes. We have true colour
modes (24-bit), we have some fairly innovative colour reduction
modes, similar to HAM but a bit different, we have YUV modes so
it'll be much more simple for us to do PhotoCD support, we've also
got some 32-bit modes where we've got a transparency channel as
AN: 24-bit colour on screen in high resolution?
CL: Yes, sure. Obviously that's not the kind of mode you'd
want to use for a games system, because it takes too much
bandwidth, the graphics take up too much space, but it's there
because the same chipset could be used in a high-end system to
provide a true-colour, high-resolution desktop interface.
AN: How much of that system is in this one central chip that
you're talking about. Is there an external graphics
CL: It's all in the one chip. Everything is in there
except RAM, ROM, and the RAMDAC for the colour tables.
AN: What is the cache situation?
CL: There's an internal cache for the PA-RISC and then there's
some external cache space as well.
AN: One of the big problems of the Amiga is the lack of memory
protection. One program crash can bring down the whole
system. Will that be eliminated?
CL: Obviously if we're going to go to the trouble of porting the
OS to another chip then we have the opportunity at that point to
get rid of all the problems that we've had to live with in
exec. We would have done it a long time ago but certain
internal features of exec made it difficult to do.
AN: It will be one of the advantages of losing
CL: Exec won't be an easy port because it's written entirely in
assembly code but it's a small, tight core so it shouldn't be too
AN: What sort of a clock speed would this turn at?
CL: Whatever clock speed the Pa-RISC chips are available
now. I know they're doing 100MHz, so...
AN: What sort of upgrade path is foreseeable for the 4000?
CL: At the moment in-house there are no designs for anything
beyond 25MHz '040. I think what we're looking at as a likely
prospect would be OEM'ing somebody else's add-on CPU card design
and then building those into the box, just as a short-term
solution. It's definitely true that we need to have a 4000
with higher specifications on the market and that gives us a
quick way of doing that.
AN: What was your function the Commodore team?
CL: I was hired on about three and a half years ago to do
multi-media standards. Basically I managed the IFF standard,
handling registrations for the forms and so forth and tried within
the organization to bring in standards from the outside world and
develop our own standards where there weren't already standards in
place, and then get developers to adopt the
standards. Unfortunately as usual in Commodore there was very
little resource to expend towards these efforts so not a lot came
of it, but we had some good work. For example CAMDI
(Commodore Amiga Midi Driver), which is essentially a MIDI
library-style system for allowing MIDI applications to share access
to the MIDI ports so that there is automatic merging of the MIDI
data. From that work a host of people ended up with another
library called Real Time Dat Library which provides the
synchronization and timing information from a master clock source
which can be generated by the library itself or come externally
from ti! me code devices, and then this master clock is
distributed to sub-tasks that want it. So for example you can
synchronize multiple animation playbacks simultaneously with sound
playback because Real Time Library helps all the allocations to
AN: Isn't all this work going to be lost when you change the
CL: No, the plan is to bring it all over. That's one of
the reasons it's going to take 18 months. A good thing is
that having picked an already existing RISC core, even while the
hardware work is progressing much of the software work can be
started immediately because you can go out and buy an HP
Workstation today with a PA-RISC chip in it. Basically we'll
have software simulation of graphics sub-systems and whatever
graphics abilities are available on the workstation, to the extent
that they can emulate, will be used. It's going to be
completely different because what we have in our own hardware is
obviously going to be much faster, but from our perspective,
developing system software, that doesn't matter much and we'll be
able to program a significant portion of the OS without having the
graphics end of the chipset done. We know what the graphics
chipset is going to do and we can write software that emulates
AN: So developers will be using an HP workstation to create the
CL: Precisely. It has to be that way because 18 months
sounds like a long time when you're thinking about how long it will
be before somebody's hardware is released, but if you're a software
developer, as you well know, 18 months doesn't seem like much at
all in order to learn a whole new system and to come out with some
decent software for it.
AN: Amiga developers will probably have a hard time learning to
program for the new machine, won't they?
CL: I think you'll find that we tried to maintain the basic chip
philosophy. It's obviously not going to be compatible on a
register level, so people who have been hitting the hardware all
along are going to have to learn all over again! But if
you're doing system programming then I don't think you've got
anything to worry about. You should be able, at the end,
without doing much more than simply recompiling your software, have
something that works. That's the goal. We have a huge
base of very good software out there. But I think you'll find
that even in public domain this is where people go ahead because
they wanna be first...
AN: One last question. If this new Amiga was produced in
two years time, what would be its main advantages over the Mac and
CL: I think that one important point is that the machine will
come as a base with outstanding graphics performance. As a
system to do 3D rendering, a as system to do commercial video work,
you're going to find that our system will be able to compete just
as well as Amigas compete today. In 18 months to two years
time, when the PCs are coming to where we are today, we'll have
gone forward another generation.
(c) NewsEdition SARL 1995.