Dimension; a 68000 muscle machine that also does some pretty good impressions. (evaluation) John J. Anderson.
It is fact: everything is bigger in Texas. That does, of course, include aspirations. For some time now we have reported on the aspiring Texan component of the microcomputer industry, represented by leaders such as Tandy, TI, Houston Instrument, Datapoint, and others. In a land where hats often take ten gallons and airports are sometimes five miles long, aspirations stand tall. And the aspirations of the Dimension 68000, from Micro Craft of Dallas, represent a tall order indeed. Candide's Computer?
Imagine a micro that was the best of all possible worlds. Basically a 68000-based muscle machine, it would represent sheer computing power. And built around co-resident coprocessor boards, it would also optionally run IBM MS-DOS software, Apple II software, CP/M software, and Unix-based software. You wouldn't have to choose between standards. That decision would no longer be necessary. There would be no reason to buy another machine.
That, in a nutshell, is the philosophy of the Dimension 68000. There is, however, more to this machine than merely a nutshell, as we shall see. But first the specifics. The Dimension system includes 256K RAM, expandable to 512K, dual half-height, single density, double sided drives, CP/M 68K, based on the 68000 CPU, Basic, a C Compiler, 68K assembler, diagnostics, and utilities. It comes with an NTSC output, a Centronics standard parallel port, an RS-232 standard serial port, and a joystick port. Ten-Gallon System Unit
As one might guess, a system unit designed to enclose a 68000 along with a maximum of four co-processor cards, while leaving room for at least two peripheral cards, is necessarily massive. The Dimension system unit is handsome, but sports a footprint that would dwarf many a desk. A vailable as internal options in this large case are 96 track, double density floppy drives, and either a 20Mb or a 50Mb hard disk unit. The system we received for evaluation was supplied with three co-processor boards (8086,Z80, and 6512), as well as a memory card that brought the system up to 512K. A big footprint, yes--and a big wallop, too. The Dimension is a Texas behemoth.
The keyboard is OEMed from Key Tronic and offers the same improved PC layout as the Key Tronic 5150 replacement for the IBM PC. This is an 83-key full-stroke keyboard with 10 function keys nestled on the left, a 10-key numeric keypad nestled on the right, and a modified Selectric-style keyboard in center stage. The keyboard is not as sturdy as the standard IBM keyboard, nor does it offer the same crisp tactile feedback, but it is completely serviceable, and includes LED caps lock readout, which the PC keyboard does not.
We got the Dimension up and running without any major problems, and hooked it to a composite monitor using the standard RCA phono jack. (An RGB card is available as an option.) The display can be configured to 20 x 20,40 x 24,80 x 25,80 x 50, and 100 x 50 rows and columns, respectively. Needless to say, the 100 column by 50 row display is not advisable on an NTSC monitor. Does it Do Jimmy Stewart?
Before you can get the Dimension into emulation mode, you must patiently move some files around. This is a little tiring, but the process is documented clearly enough. Finally you end up with a system disk--the first disk to boot on the Dimension when out of native mode. This system disk contains the emulation software to tell the hardware which impersonation you wish it to do. So far so good--we told the Dimension to become an Apple, and there before us appeared a 40 x 24 all-uppercase display with no screen editor and the familiar > prompt. Very convincing!
But a funny thing happened to our video output on the way to becoming an Apple--the top half of it began to tear. By playing with the vertical hold, we got the image to stick, but it remained jittery, with an unsightly bend to the left. A call to Micro Craft got us a ver nice, helpful response, unfortunately to the effect of "play with the vertical hold." This was slightly unsettling. We were assured, however, that this fault has been corrected in subsequent models. Compatibility and Inability
Then we started trying to load software. As has been my experience since the advent of work-alikes, compatibles, and emulators, some stuff works; some stuff sort of works; and some stuff just doesn't work. That's the way it is.
Such was also the case with IBM emulation. Lotus booted up, as did WordStar, and even Flight Simulator. A little further experimentation revealed that although Flight Simulator would boot, it didn't quite run correctly. We could not avoid backing up into Lake Michigan, no matter how hard we tried. Beyond that, not much else would even boot, and that which did ran only up to a point. We have determined time after time that copy protection is the worst foe of compatibles, and I believe it to be the culprit in this case as well. As protection schemes almost always reflect directly the very peculiarities of a given piece of hardware, they are by their nature the toughest conditions to emulate. That's the way it is.
On the CP/M front, things only got worse. I'll admit we don't have too much CP/M software lying around the lab anymore, but none that we did have would boot on the Dimension.
I was disheartened. The Dimension represents a valiant attempt to encompass the best of all possible software worlds, but does not really deliver on this promise. I placed a call to Don Bynum, head of the Dimension project for Micro Craft. I told him of my reservations and reminded him that for the price of a fully-blown Dimension, one could very nearly buy a full-blown IBM PC, with a full-blown Apple II, and a full-blown Kaypro CP/M machine. Sure, they would take up a lot of room, but at least you would know all your software would run. Why, then, opt for the Dimension?
Well somewhat to my surprise, Don had some very plausible answers to that question. I soon realized that I might be going about my hardware evaluation from entirely the wrong perspective. Can the Candide angle. Go for Casey Jones. Desktop Diesel
Don described the Dimension as a computing locomotive. He suggested that the unit should not be reviewed as an emulation machine at all, but as a high performance 68000 machine, that at the same time offers a link back to some older software bases. He put forth the case of an engineer, involved in modeling and simulation, who already uses an IBM PC or Apple II to aid him in his work--but all he can do currently with a micro is the "administrative" part of his job. He can write his weekly reports on it. He can do his project budgets on it, and he can sum up his data in some primitive ways with it. But he cannot do actual modeling with it, because it is not powerful enough. There simply isn't enough RAM, or more significantly enough CPU power, to take care of the actual job he has at hand.
Using the Dimension, that engineer can do the things he would otherwise need to timeshare on the VAX or other comparable mini or mainframe to accomplish. As an example, he can do a 1000-point Fast Fourier transform in double precision in something under 20 seconds, including a hi-res output of the waveform. So the muscle is undeniably there, and solely in the hands of the person at the desk. At the same time, our hypothetical engineer can also drop his IBM emulator card into the Dimension, and continue to use the Lotus or WordStar software that he has been using all along. Data by Rail
Bynum emphasized that emulation on the Dimension is not an end in itself, but a bridge between existing datafiles and the world of the 68000. Using the Dimension in emulation mode, existing datafiles can be ported over from existing environments to the environment of the 68000 processor, without raising the prospect of rekeying. To a CPA, or a small businessman with dozens of existing data disks, the Dimension offers a reasonable means to enter the CP/M 68K or other heavy-duty 68000-based sphere, without scrapping the work that has led to the existing, large database. This is a critically important consideration to those who have reached the limit of their current systems, but abhor the prospect of a changeover because it would mean massive and costly amounts of busywork. Around the Bend, Unix
Further, the Dimension offers Unix potential for the future. As it rather spooks me, I offered that Unix might be an anchor around the neck, though a different kind of anchor than CP/M had proven to be. Don agreed that CP/M had "set the industry back five years," but responded that rather than another anchor around the neck, he viewed the coming of Unix as a potential "time bomb in the pocket." He continued:
"I'm a Unix enthusiast, and I went to a Unix user's group meeting in Dallas recently. I would typify the people who went to that meeting as falling into two classes: there were a bunch of guys with beards and sandals, who looked as if they might be offended at the statement that Unix could be used for useful work. They have been experimenting with operating system theory in Unix for ten years now. All of a sudden, though, that group is shrinking. AT&T has budgeted $150 million dollars to convince the business world that they will need Unix. That is creating a group that expects real results. And that group is growing. I think Unix is the best alternative that is out there right now.
"It does have some heavy burdens that come with it, though. It is like the operating system on a big computer--it uses loads of overhead. Like a big computer operating system, there are lots of things that can make doing a big job easier, too. But like a big computer operating system, if you take any kind of a power hit in the middle of the day, the consequences can be pretty grim. It is not as bad as it used to be, however. A benchmark of this was the track record of Dimension Unix during fall Comdex. We demonstrated our Unix system there--we ran it all five days--and suffeed three power failures in our building during those five days. We lost exactly one file. I was astonished. The only guy who was more surprised than I was our Unix engineer. He was first surprised, second happy, and third wondering when and where the other shoe would fall.
"The key is that Unix offers an incredibly powerful development tool, and while the shell itself is far from user-friendly, user-friendly shells can be developed on top of it. That is what is beginning to happen. The Dimension is sitting above the PC AT and AT&T entries in terms of performance, because we're using the 68000 as opposed to the 80286, and we run Unix with two 68000s--one 10 Meg component that's actually running Unix and one that's acting as file server and handling the I/O stuff. This dual-processor arrangement squeezes the most out of the system."
With CP/M 68K, the Dimension is also well-placed in the single-user market. People who need a tremendous amount of computing power will have a tough time finding a bigger engine in a desktop micro. Bynum pointed out that there are four Dimensions being used at the Jet Propulsion Laboratory for heavy number crunching. As a result, JPL saved the cost of another minicomputer system. Changing Pitch
Though he admitted that the Dimension was originally pitched as "the machine for all software," the emphasis that Don now underscores is the Dimension as a superlative 68000 machine, with the plus that in emulation mode, lots of other stuff can run. "There is an attraction, I suppose," he said, "to the fact that with a straight face you can say that the Dimension is a machine that will run most of the software across the range from the Apple II to Unix. That's a pretty grand statement. But I don't know anyone who really wants to run most of the software across the range from the Apple II to Unix. Maybe a magazine editor like you, or someone like (industry and software analyst) Portia Isaacson. I hope Portia doesn't get mad at me, because we're old friends. But I can't name anyone else who is in a position to really want to do that kind of thing. And that's not where we're at."
I have to admit, Don had me there. For my less than typical needs, I would have welcomed the Dimension as the "universal" software machine. At the same time, I realize that there aren't a heck of a lot of other people in my position. I can't speak for Portia, of course (no one can do that). And from the point of view of an engineer, the Dimension is without question a powerful contender. Its benchmarks are unbeatable. Native mode Fortran and Pascal on the Dimension run rings around the IBM PC AT.
For sheer power, the Dimension is a winner. Space limitations preclude the inclusion of a comprehensive list of Dimension-compatible software packages, but you can download a list from the Creative Computing SIG or request one from the manufacturer.
Products: Dimension 68000 (computer)