Dimension 68000
Kaypro II | |
Dimensions | 18 by 18 by 6 inches (46 cm × 46 cm × 15 cm) |
---|---|
Mass | 22–27 lbs |
Successor | New Dimension 68000 (1987) |
The Dimension 68000 is a microcomputer introduced by the Micro Craft Corporation in 1983 that sought to emulate the Apple II, the IBM PC, and various CP/M-centric computers through a family of coprocessor expansion cards and emulation software. The Dimension 68000 can also run as a standalone computer based on the Motorola 68000 from which it gets its namesake.[1] The computer is mostly the brainchild of Mike Carpenter, a former executive of a scientific instrument manufacturer who incorporated Micro Craft in Dallas, Texas, to develop the Dimension 68000. It had a market lifespan of three years and received mixed, mostly positive, reception from the technology press. Criticism was leveled at the $6,250 price tag for the computer with the full deck of coprocessor cards, as well as the extent of the emulation power of those cards.
Specifications
Main unit and keyboard
The Dimension 68000 is a
The motherboard of the Dimension 68000 comprises a four-layer
The disk drives of the stock Dimension 68000 consist of two half-height,
The computer has no prescribed monitor, and purchasers were expected to buy one separately.
Expansion bus, coprocessor cards, and emulation modes
The Dimension 68000's coprocessor expansion cards were the main draw of the computer because it promised a cross-platform experience in one unit. Regardless, purchasers could have ordered a Dimension 68000 without any cards and have it still be functional as a 68000-based computer,
The Dimension 68000 was described as a "hybrid emulator"—that is, each of the coprocessors performed the bulk of code execution in their respective emulation modes, while certain memory-resident programs handled elements of emulation in the background. The Motorola 68000 additionally handled certain interrupts the coprocessors by themselves could not execute—chiefly regarding display output and disk reading and writing.[8]
From its inception through to its demise, Micro Craft only offered three expansion cards for the Dimension 68000—an
B: IBM
, to boot into the IBM PC emulation mode. Both disks could then be removed from the drives, and specific IBM PC software can be loaded from disk.[13]Apple II card
The Apple II coprocessor card runs off an
As opposed to loading IBM emulation mode, which only requires the user enter B: IBM
at the Dimension 68000's native CP/M prompt, the Dimension 68000's Apple II emulation mode requires the user enter several
B: APPLE
. These arguments specify the presence of a printer, how many disk drives if any are to be emulated, the type of keyboard, the type of display, and so on.[16]The Apple II emulation mode additionally requires the user provide their own copy of an operating system, such as Apple DOS or ProDOS. Once booted into a Applesoft BASIC prompt, however, the interpreter recognizes all BASIC syntax, down to the PEEK
s and POKE
s.[11] As well, the Apple II coprocessor card emulates a full deck of Apple II peripheral cards: in slot 0 is the 16 KB Language Card; in slot 1 is the parallel card; in slot 2 is the serial card; in slot 3 is the 80-Column Text Card; in slot 6 is the floppy controller, with two virtual Apple disk drives plugged in; and in slot 7 is the hard drive controller card.[17] Applesoft BASIC can be used to invoke any of these cards with expected behavior; for example, to load the 80-Column Text Card, the user enters PR#3
at the prompt.[11]
IBM PC card
The IBM PC coprocessor card runs off an
The standard IBM
emulation program on the IBM "emulation master" disk emulates an IBM PC with a
IBMEXP18
, was an experimental "enhanced" IBM emulation mode, version 1.18, which as of September 1984 had not been fully debugged; it added direct I/O to the NEC 765 and expanded the capability of the RS-232 serial port under IBM PC emulation. All four of the aforementioned emulation programs can be run without passing any arguments, unlike with APPLE
. In this way, the emulation programs defaulted to running the maximum amount of RAM possible, minus some reserved for the emulation software. Running IBM
(CGA, 80-by-25 text) on a machine equipped with 512 KB of RAM, for example, left 412 KB addressable to the virtual machine. Some arguments could be passed to these emulation programs: MEM=n
limited the memory to a set amount; INTENSITY
rendered characters with the intensity bit set to high as reverse video (see IBM Monochrome Display Adapter § Capabilities); and CONFIG=$$$$
is a software analogue to the DIP switches on an IBM PC's motherboard, used to set certain hardware parameters.[17]A
IBMEXP18
to get this), and channel 2 of the PC speaker not working, among others.[17] By November 1984, the card still had no support for channel 2 of the PC speaker, and it became known that interrupt calls to the sound generator would still be handled as no-ops, leading to erratic behavior in sound-capable video games, such as Microsoft Flight Simulator.[15]Users could exit IBM PC emulation mode by invoking Control-Alt-Delete or by pressing the reset button on the Dimension 68000.[17]
Z80 CP/M card
The CP/M coprocessor card runs off a 4-MHz
B:
, including C:
through K:
(skipping J:
however), with K:
being a RAM drive. KAYPRO
, OSBORNE
, and CROMEMCO
only support drive letters A:
and B:
.[20]Native software
The native operating system of the Dimension 68000, as included in the system disk, is CP/M 68K, a port of
Unibasic, a BASIC dialect developed specifically for the Dimension 68000 by Dallas-based RD Software, was also included in the package.[25] Although native to the Motorola 68000, with all 16 MB of the Motorola 68000's address space supported by it, Unibasic was very closely based on Applesoft BASIC. For example, Unibasic's PEEK
s and POKE
s for manipulation of printers, video display, and keyboard input expect memory addresses identical those used by Applesoft for such devices (meanwhile APEEK
and APOKE
could be used to read and manipulate the absolute memory addresses of the Motorola 6800).[26] Unibasic adds a VARPTR function (VARiable PoinTeR, i.e. return the address of a variable), a Mode statement allowing the user to change the screen format on the fly as well as the behavior of variable scrolling, and a Call statement supporting up to fifteen arguments.[26]
At least one third-party software developer released a software package specifically for the Dimension 68000. CLYDE (Custom Logic You Design Easily), a software package for
Development and release
The Dimension 68000 is primarily the brainchild of Mike Carpenter, the former president of Scientific Machines, a company that manufactured scientific instruments.[28] Development of the computer commenced on Micro Craft Corporation's incorporation in Dallas, Texas, in November 1981. He set out the Dimension 68000 to be the epitome of a "compatible" computer system—interoperable between all the popular computing platforms, providing a powerful microprocessor, and following design philosophies to make the computer as resistant to obsolescence as possible.[29] However, a proprietary bus had to be devised, according to Carpenter, because off-the-shelf standards did not provide "access to all the signals [his team] had to make [the machine] flexible".[6] Carpenter employed the help of several employees from companies for which the Dimension 68000 emulates, including IBM and Apple.[28]
The first shipment of Dimension 68000 commenced in October 1983.[30] The price of the base unit on launch was $3,995.[31] For a package with all three emulation cards, the price reached $6,250 (in April 1984; equivalent to $16,302 in 2021). A network of 80 to 90 dealers was established the previous month to distribute 250 Dimension 68000s across the United States.[32] Another round of shipments occurred in April 1984, by which point Micro Craft had culled some of their dealers, leaving 77 in their network.[33] In 1984, the computer was introduced worldwide, imported to the United Kingdom by the Wembley-based Tashkl Computer Services and to Canada by British Columbia–based Popular Electronic Products store.[34]
Micro Craft filed for
Reception
Advertisements of the Dimension 68000 in computer magazines generated massive hype for Micro Craft, the company receiving over 50,000 queries by April 1984, according to Barbara Henry-Arnold, Micro Craft's director of communications.[38] Interest was mostly fueled by its advertised emulation prowess.[15] By the middle of 1985, however, Micro Craft was downplaying its role as an polymathic tool in favor of the potential for its Motorola 68000 to cooperate with the coprocessors in the computer's native mode.[39]
Reviewing a pre-production unit, although he encountered some problems in IBM PC emulation mode, Jim Heid of Microcomputing called the Dimension's emulation powers "amazing" in its breadth.
Personal Computer World's Peter Bright called the Dimension a technically "very innovative product" with its emulation modes "well executed for the most part" but cast doubt on its role in the mid-1980s computer marketplace: "My only worry is whether this is a case of building a machine for its own sake rather than because the market needs it."[43] Bright criticized the use of CP/M-86 as a single-user operating system but saw potential if more popular multi-user OSes such as Unix came to support the Dimension 68000 and wrote that the range of its emulation was unparalleled. Bright wrote that the machine and its documentation was beginner-unfriendly.[43] Popular Computing's Rick Cook wrote that, counter to the interest of prospective buyers who had been wooed by advertisements in computer magazines, most would be disappointed: "The Dimension 68000 is powerful, but it cannot do everything."[15] Cook deemed the computer's native number-crunching performance good and found it one of the cheaper 68000-based microcomputers on the market, albeit at a price not factoring in a hard drive, which was seen as an increasingly important device for such micros. He saw the coprocessor arrangement useful in applications besides emulation, such as in Unix-like operating systems that could take advantage of more than one processor. But at "the $5500 cost of the Dimension emulation package," Cook wrote, "you are close to getting an IBM PC or PC clone, an Apple II, and a low-priced CP/M system, such as the Kaypro II."[15]
Stephen T. Satchell of
See also
- Challenger III by Ohio Scientific, a computer that had three processors: a 6502, a Z80, and a Motorola 6800
- Omni Convertible by Omnidata, another triple processor computer system
Citations
- ^ Satchell 1985, p. 40–41.
- ^ Nadeau 2002, p. 83; Kelly & Grimes 1985, p. 145.
- ^ a b c d e f g h i Bright 1984, p. 153.
- ^ a b c d e Heid 1984, p. 69.
- ^ a b c Satchell 1985, p. 40.
- ^ a b c d e Heid 1984, p. 70.
- ^ a b c Anderson 1985, p. 40.
- ^ a b Cook 1984, p. 68.
- ^ Cook 1984, p. 68; Anderson 1985, p. 40.
- ^ Allswang 1984, p. 42; Anderson 1985, p. 40.
- ^ a b c Rimmer 1984, p. 39.
- ^ Heid 1984, pp. 69–70.
- ^ a b Cook 1984, p. 70.
- ^ Cook 1984, p. 66.
- ^ a b c d e Cook 1984, p. 72.
- ^ Cook 1984, p. 70–72; Bright 1984, p. 155.
- ^ a b c d Bright 1984, p. 155.
- ^ a b Nadeau 2002, p. 83.
- ^ Micro Craft Corporation 1984, pp. 27–28; Rimmer 1984, pp. 39–40.
- ^ Micro Craft Corporation 1984, p. 25.
- ^ Bright 1984, p. 154; Heid 1984, p. 72.
- ^ Bender 1983, p. 45; Bright 1984, p. 154; Anderson 1985, pp. 40–41.
- ^ Gill 1985, p. 72.
- ^ Heid 1984, p. 70–71.
- ^ Allswang 1984, p. 42.
- ^ a b Heid 1984, pp. 71–72.
- ^ Harvey 1984, p. 229.
- ^ a b Watt 1984, p. 44.
- ^ Heid 1984, p. 67.
- ^ Bender 1983, p. 45; Staff writer 1983, pp. 100–101.
- ^ Staff writer 1983, p. 100.
- ^ Bender 1983, p. 45.
- ^ Siegmann 1984, pp. 78–79.
- ^ Bright 1984, p. 157; Rimmer 1984, p. 41.
- ^ Staff writer 1985, p. 2.
- ^ Eckhouse 1986, p. 29.
- ^ Satchell 1989, p. S18.
- ^ Watt 1984, p. 45.
- ^ a b Anderson 1985, p. 41.
- ^ Heid 1984, pp. 72–73.
- ^ Heid 1984, p. 73.
- ^ a b c d Rimmer 1984, p. 41.
- ^ a b Bright 1984, p. 157.
- ^ Satchell 1985, p. 41.
References
- Allswang, John M. (July 1984). "The Dimension 68000: Emulating the four top micros". Interface Age. 9 (7). McPheters, Wolfe & Jones: 42–44 – via ProQuest.
- Anderson, John J. (April 1985). "Dimension". Creative Computing. 11 (4). Ziff-Davis: 38–41. Archived from the original on August 17, 2022 – via Gale.
- Bender, Eric (September 12, 1983). "Start-Up's 68000 Micro Runs 8- to 32-Bit Ware". ISO World. 6 (16). CW Communications: 45 – via the Internet Archive.
- Bright, Peter (September 1984). "Dimension 68000". Personal Computer World. 7 (9). Incisive Media: 152–155. Archived from the original on June 4, 2020 – via Gale.
- Cook, Rick (November 1984). "A Machine for All Software?". Popular Computing. 4 (1). McGraw-Hill: 64–66. Archived from the original on July 2, 2021 – via Gale.
- Dimension 68000 Z-80 Coprocessor and Emulators Reference Manual (PDF). Micro Craft Corporation. 1984 – via Bitsavers.
- Eckhouse, John (February 20, 1986). "A Device That Turns an Ordinary TV into a Wizard". San Francisco Chronicle. Chronicle Publishing Company: 29 – via ProQuest.
- Gill, Phillip J., ed. (October 1985). "Micro Craft's Dimension 68000". Unix World. 2 (9). Tech Valley Publishing: 72 – via the Internet Archive.
- Harvey, Patrick L. (May 31, 1984). "Workstation's software turns logic designers into custom IC experts". Electronic Design. 32. Endeavor Business Media: 229 – via Gale.
- Heid, Jim (February 1984). "Dimension 68000: The Epitome of Compatibility?". Microcomputing. 8 (2). CW Communications–Peterborough, Inc.: 66–73. Archived from the original on August 10, 2021 – via Gale.
- Kelly, Brian W.; Dennis J. Grimes (1985). Kelly/Grimes IBM PC Compatible Computer Directory. Wiley. ISBN 9780471878193– via Google Books.
- Nadeau, Michael (2002). Collectible Microcomputers. Schiffer Book for Collectors (Illustrated ed.). Schiffer Publishing. p. 122. ISBN 9780764316005– via Google Books.
- Rimmer, Steve (August 1984). "Dimension Review". Computing Now!. 2 (5). Electronics Today International: 38–40 – via the Internet Archive.
- Satchell, Stephen T. (January 21, 1985). "Dimension 68000: Jack of All Trades, but Master of None". InfoWorld. 7 (3). IDG Publications: 40–41 – via Google Books.
- Satchell, Stephen T. (January 16, 1989). "Two Emulators Bring IBM PC Programs to the Macintosh II". InfoWorld. 11 (3). IDG Publications: S18 – via Google Books.
- Siegmann, K. (April 2, 1984). "Micro Craft Corp. Unveils New M68000-Based Microcomputer". Computer Retail News (47). UBM LLC: 78–79 – via Gale.
- Staff writer (November 21, 1983). "Micro Craft Begins Shipping a Computer It Claims Is Universal". Computer Retail News (34). UBM LLC: 100–101 – via Gale.
- Staff writer (July 25, 1985). "Zaisan, high-tech firm, files for reorganization". Houston Chronicle. Hearst Corporation: 2 – via ProQuest.
- Watt, Peggy (April 30, 1984). "Rana Pushes Hybrid Computing". InfoWorld. 6 (18). IDG Publications: 44–45 – via Google Books.