Emulation Rambler

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             Emulation Rambler: PC-Task 4.2 and PCx 1.1 Review
                           By:  Jason Compton 
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They're both the results of years of development.  PC-Task's Chris Hames
has been working to perfect PC emulation on the Amiga since the first
shareware release of PC-Task, some five years ago.  Back then, he made the
other offerings (the very early Transformer, and IBeM, later CrossPC) look
silly.  PC-Task 1 and 2 were no great shakes, though.

When Emplant got PC capability, finally, some people were disappointed that
it didn't seem to deliver a whole lot of power.  The same went for PC-Task
3, which was an improvement on the old design and had better graphical
capabilities than the predecessors, but wasn't outstanding.

Now PC-Task 4.2 and Emplant PC's successor, PCx, are out.  PC-Task boasts
486 and FPU processor emulation (the FPU support is new to 4.2), while PCx
is Pentium/586 compatible, FPU inclusive.  Both can support VGA-style modes
in addition to the older fallback graphical setups.  PC-Task can promote
any of its screens to a display database-compliant system (CyberGraphX
highly recommended), while PCx can presently only put VGA 320x200x256 on a
CyberGraphX screen, the others use ECS/AGA.  PC-Task has more expansive
graphical options, allowing you to place the emulation on a Workbench
window and offering frameskip features (for added speed).

The reasons for wanting or needing PC emulation are legion.  Everyone can
probably come up with something.  So here's a quick list of reasons you can
eliminate from your list right away.

If you want to:

 - Run Windows 95
 - Play Duke/Quake with your buddies, or most any commercial PC game
   released in the past 18-24 months minimum for that matter

You should probably not bother.  Because of the limitations in speed we all
face, with a functional maximum of an 060 right now, getting the 486DX4 or
Pentium performance levels is just not feasible.

On the other hand, if you need to run Windows 3.1 and don't mind the sort
of performance 386es are getting, and you have a fast Amiga, you could be
in business.  I personally just spent part of an afternoon helping a friend
configure a large Word document table on a 386/20 running Win 3.1.  It's
slow, but doable.  If you're going into PC emulation with that sort of
expectation, and have the 060 to back it up, you'll be fine.

Personally, what I typically do with PC emulation is play classic PC games.
They're very abundant, and are quite often games that never made it to the
Amiga.  My standby is Wasteland (which if you read my last round of PC
emulation reviews you've already heard too much about), but there are a
number of game packs out there for the PC.  You can pick up a handful of
classic titles on CD-ROM for very cheap.  (My most recent project has been
to get Pizza Tycoon to run on either emulator, but I've been stymied so
far.)  The SSI AD&D games are another good example of games you might
consider picking up for the PC for a song.

The emulations of the PC by both PC-Task and PCx are impressively thorough.
Both can use the emm386 memory manager (although for speed reasons it's
discouraged), both offer the ability to use large amounts of the Amiga's
memory (PCx requires that it be from a single contiguous block, PC-Task can
mix memory), and both support serial/parallel/hard drive/floppy and CD-ROM
access.

This brings up an important point.  If you're going to be serious about
emulating a PC (or a Mac, for that matter), you should really have a CD-ROM
drive or a high-density floppy.  Preferably both.  You're going to have
massive headaches if you don't.

Hard drives are handled by both emulators in similar ways.  Both support
"hardfiles", which first became popular with PC-Task and later with Mac
emulators.  Hardfiles are inefficient but useful-in-a-pinch ways to set up
hard drive compatibility--they're large AmigaDOS files which the program
treats as a physical device.  PC-Task and PCx also support real, dedicated
partitions, a much better choice.  Unfortunately, they do not share
formats, and PCx's is a custom filesystem, as opposed to a CrossDOS
filesystem as PC-Task uses.

The CD-ROM compatibilities are not equal.  PC-Task has a decided edge.
Very often, a CD would be recognized perfectly by the AmigaOS and by
PC-Task but PCx would refuse to read it.  This frustration is compounded by
another advantage PC-Task has over PCx: the ability to copy between PC and
Amiga drives at the PC prompt using special tools included with the
emulator.  That means if you can't read a CD on the PCx side, you're stuck
using clunky floppies to transfer data across.

Both offer sound emulation of the PC speaker.  PCx goes further to
implement a partial SoundBlaster emulation.  It's an improvement, and will
be nicer when it's complete.  Both also support mice, and the ease of use
of the mouse drivers is improving.

In terms of compatibility, the major differences in compatibility come in
identifying their graphical capabilities to programs.  Modern PC programs
should have no trouble, but older programs which hit hardware may get
confused.  The King's Quest games are not fully compatible on either
emulator, for example.  But on the processor level, both emulators are very
well set up for what they're doing.

Both rely on "CPU Transcription" or "Dynamic Transcription" to work their
magic.  The technicalities are beyond my ability to explain them, but in
short, rather then simply interpreting each PC instruction into an Amiga
instruction and back again as it comes, both emulators can pre-interpret
the code for faster performance down the line.  In PCx, this involves
configuring the transcription cache with up to 1 meg of memory.  In
PC-Task, you run the PC-Task Dynamic executable instead of PC-Task
Interpretive.  PC-Task Dynamic lets you select a buffer size, from "Tiny"
to "Huge".  The buffer is set up relative to the memory the PC side is
using, with Huge creating a buffer many times larger than the PC's memory
(and thus limiting your emulation options.)  Having a lot of memory is also
a very good idea for emulation.

Benchmarks are never reliable for emulation.  I conducted tests that were
not used by either company for advertising purposes, using the Bytemark V2
software in 32-bit mode.  Unfortunately, the results are more indicative of
how you CAN'T rely on statistics alone.  The results indicate that PC-Task
is far, far faster than PCx, and that's just not the case.  In fact, PCx
has surprised me in actually being faster than PC-Task, when PCx was
running a game on an AGA screen and PC-Task ran the same on either an AGA
or CGX screen.  These results came using a Large transcription buffer for
PC-Task and the full 1 meg buffer in PCx.  (The poorly documented Turbo
option of PCx was used but to no effect on the performance scores.)

A rather crude benchmark program, CI, returned that PCx (in 1 meg
transcription mode) resembled a 27.2 Mhz 386 on my system, while PC-Task
looked more like a 39.9 Mhz 386.  The performance is based on the
CyberStorm Mark II 060 card.  These numbers should be considered suspect.

I tried a more real-world benchmark involving processing and disk I/O (the
sorts of things you'd be doing in using a computer)  Zipping the DOS 4 GW
executable yielded a surprise.  PCx, which as I previously mentioned is
often faster in the real world, was far slower than PC-Task.  PC-Task in
Dynamic mode with a Large buffer buttoned up the file in a mere 7.84
seconds.  PCx took 33.82 seconds, just slightly faster than the PC-Task
Interpretive (no cache) speed of 33.93 seconds.  By contrast, a real-world
Pentium 100 is more than twice as fast as the PC-Task result.

PCx has a nice "hard reboot" option which PC-Task is lacking, and it's come
in handy more than once.

PCx is somewhat cheaper than PC-Task--about US$20.  And you do get a lot of
emulator.  On the other hand, PC-Task 4.2 has the look and feel of a more
complete product.  The CyberGraphX support is wholehearted, the CD-ROM
driver works better, and the hard drive integration with the Amiga is much
better.  At present, I still have to recommend PC-Task over PCx, but it's
very close, and is not the best solution in ALL situations.  For most
things, however, I think PC-Task is presently the way to go.

PC-Task published worldwide by:
Quasar Distribution
PO Box 101
Vermont, VIC 3133
Australia
+ 61 3 9887 2411 voice
+ 61 3 9887 2511 fax
http://www.ozemail.com.au/~pctask
pctask@ozemail.com.au e-mail

PCx is published worldwide by:
Blittersoft
6 Drakes Mews
Crownhill Industry
Milton Keynes
MK8 0ER
United Kingdom
+44 1908 261466 voice
+44 1908 261488 fax
http://blittersoft.wildnet.co.uk
sales@blittersoft.com

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