Shiuming Lai gets a new
Atari computer
All right, I'm cheating - what with
the imminent threat of Christmas looming upon us, the
last thing I can afford is to splash out on a new computer
for myself, so I did the next best thing and grabbed
hold of a freeware emulator.
The Steem Engine (STE-EMulator) is
a brash young upstart on the Atari ST emulation scene,
developed by two brothers initially as a joke to see
how far they would get before failing. As it happens,
they have been doing very well and the project is rapidly
gaining momentum. We're already on the third release
(note: just as we went to publish, v1.3 was released),
now implementing MIDI support, and programmers can download
a debugging tool to assist its development into a more
faithful emulation.
Practicalities of emulation
Different types of emulation exist to
serve the varying needs of users. Some only give operating
system level emulation, using a largely compatible OS
standard, maybe with enhanced functionality. For example,
a PC (or Mac) running the appropriate version of MagiC
can execute cleanly-programmed Atari software with higher
screen resolution and colour depth based on the host's
hardware ability, and integrate an Atari environment
with other systems. It's possible to effectively access
network volumes, DVD-ROM content and massive partitions
as if they belong to the Atari OS, even share them with
the native OS.
On the other hand, there are complete
system emulators like Steem. Here, the OS functionality
is achieved by using binary images extracted from the
actual TOS ROMs fitted to real machines, defining the
"official" capabilities. At the same time
they emulate the hardware, for software which bypasses
the OS to side-step its limitations. To all intents
and purposes, this type of emulator is intended to give
you a logical replica of the real thing, warts and all.
You have the GEMDOS capacity limitations, so don't try
manipulating huge files on your PC's hard disk directly
from Steem, that's asking for trouble!
Emulators of the latter type are unequivocally
aimed at game and demo connoiseurs, where hardware-level
emulation is essential as most such software is extensively
hard-coded for performance.
Like all emulators, Steem has to know
where to find resources. First time it's started, it
prompts you to select drives for its file system (either
real Windows drives or disk images, more common for
games), which TOS image to use and so forth. I find
disk images a bit of a nuisance, though this is no fault
of any emulator programmer. PCs are simply not as flexible
as Ataris when it comes to floppy disk drive handling
(program an Atari to access track 90 of a DD floppy
disk and it will have a good try!) so extended formats
are out, as is trying to run most commercial games and
demos straight from floppy.
Further fine-tuning can be done after
the initial configuration. One of the things I really
like is its screen handling. Different draw modes are
available to suit the power of your PC (update 1, 1/2,
1/3 or 1/4 frames...), as well as full and windowed
mode. The latter is implemented with a superb real-time
scaling routine that renders the display with anti-aliasing,
plus a snap setting for nice and sharp integer-scaled
output. Aspect ratio is accounted for, with horizontal
line-doubling to avoid ST medium resolution looking
like a panorama. Steem can be associated to the popular
MSA (Magic Shadow Archiver) image file format or memory
snap-shots.
How to spot an emulated ST
One of the first give-aways that an ST environment is
not the real thing is the mouse pointer movement. Particularly
on PCs under Windows 9x, where the PS/2 mouse tracking
has a very low sample rate and looks jerky no matter
how fast the processor. I've got a Microsoft PS/2 mouse,
with Intellipoint software on my Windows 98 SE installation,
giving very smooth movement in its native environment
(and MagiC PC), but doesn't improve things for Steem.
In fact, there is also a tracking latency which makes
the cursor feel like it has inertia. Seasoned Atari
users accustomed to the razor-sharp mouse handling of
their real TOS machines will either get motion sickness
or feel frustrated as they have to compensate by reducing
their control speed to a snail's pace. STew! 1.0 (another
new arrival, but not STE-specific and based on the source
code of veteran emulator, WinSTon) is rather better
in this respect.
Another tell-tale sign is the system
noises. Speaking to a colleague on the telephone some
time ago, I heard a familiar noise, the ST key-click.
However, it didn't quite have the same tone to it. "That's
not a real ST. You're using MagiC Mac, aren't you?"
I said. Steem's whole PSG and DMA stereo emulation is
not yet anywhere near complete and this is reflected
in the sounds (key-click included) or lack of them in
places.
On with the testing
Originally I had the bright idea of zapping my Mega
STE's hard disk contents over to the PC by network,
as Elmar Hilgart in Germany was due to send me a review
sample of his Ethernet adaptor. Murphy's Law did a good
job of making sure this arrived too late so I resorted
to Sneakernet. I could have used a CD-ROM compilation
but felt the best way to test was with software I'm
familiar with. Some of the pictures here give a taster
of what's possible with Steem. Rather than write a long
compatibility list which is bound to improve, I will
just say if it worked, it worked well, except for the
sound as mentioned above.
Remember those ST games which were
a tad sluggish? Steem has variable clock speed emulation,
all the way up to a heady 128 MHz (nice that it's so
precise, whereas some other emulators just run as fast
as the host allows with no indication of relative speed).
GEM is satisfyingly snappy though my attempts to augment
that by installing NVDI 5 have failed so far. Interestingly,
the extra speed doesn't accelerate all games. Those
that it did exhibited dramatic improvement.
For a moment I had manic visions of
becoming a MIDIMAZE 2 death-match champion as this great
network game thundered along at a fantastic rate. Sadly,
my Mega STE and PC would not talk to each other, both
thinking they were playing solo. Russell Hayward, co-author,
confirmed to me, "At the moment MIDI only works
to musical instruments, it uses the Windows multimedia
system to send it through, not direct to the hardware."
Yes, the MIDI does work for musical
instruments, I got one sequencer and a handful of file
players to work. Definitely no replacement for the real
thing!
Steem's stability is generally very
good. However, I did experience frequent host system
freezing in ST monochrome mode, at various speeds past
1 GHz (using an overclocked PIII 933EB processor which
is otherwise perfectly stable and actually running cooler
than it did before I made any modifications, when I
clocked it at factory specification). I got the same
problem with TOS 1.02 and TOS 2.06 images, and this
was with Windows 98 SE. No such problem with Windows
2000 (SP1), yet. At first I suspected the latter OS
was fine because it doesn't yet have a driver for my
default audio card, so I switched over to my Creative
SoundBlaster Live! 1024 "joystick-card" in
the Windows 98 SE test environment, but still no difference.
The real to logical (emulated) I/O device mapping initialisation
clearly occurs before this mysterious freezing (which
typically manifests during the GEM loading stage or
soon after that once on the desktop).
If development of Steem continues
at its current rate I've no doubt it will become the
first choice in virtual STE computing for PCs. Even
in its current form, it's well worth the download, you'll
be up and running in a matter of minutes. Only by many
people using it and giving feedback will it progress
towards its ultimate goal.
Steem's fancy on-screen display.
The media access indicator is a nice touch.
Microdeal's Concerto MIDI sequencer.
In principle it works,
but the timing is incorrect (not surprising).
Now that's what I call a processor
upgrade!
One of the ST's very best racing
games. I bought a copy purely
on the basis of watching this fantastic intro animation
in a
shop, which one should never do.
Here's Stardust, a top STE/Falcon-only
game. Only the sound
isn't all there.
Even undocumented screen modes
with overscan and palette
switching are attempted. Pinball fans will have to wait
with
baited breath to see if Obsession will ever work, though.
Kick smiley butt: Using Steem,
you could run rings around
everyone in MIDIMAZE 2, if only the MIDI link would
work...
A pretty lethargic game on
a real ST, no better at full-Steem
ahead, but really zips along on the rival STew! emulator.
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