Exidy Sorcerer
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The Sorcerer was one of the early home computer systems, released by the videogame company, Exidy. It was comparatively advanced when released, given its competition of Commodore PET and TRS-80, but due to a number of problems including a lack of marketing, the machine remained relatively unknown. Exidy eventually pulled it from the market in 1980, and today they are a coveted collector's item.
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[edit] History
The Sorcerer was first launched in 1978 (although some sources claim 1977, which appears unlikely), at a price of $895. It was powered by a Z80 running at 2.106 MHz with 8 kilobytes of RAM. The expansion systems and drives were released at the same time.
Sales in Europe were fairly strong, via their distributor, CompuData Systems. The machine had its biggest brush with success in 1979 when the Dutch broadcasting company, TELEAC, decided to emulate the BBC's success and introduce their own home computer. The Belgian company DAI was originally contracted to design their machines, but when they couldn't deliver, CompuData delivered several thousand Sorcerers instead.
By 1980 Exidy had already decided to give up on the machine, but sales in Europe were strong enough that CompuData decided to license the design for local construction in the Netherlands. They built the machine for several years before developing their own 16-bit Intel 8088–based machine called the Tulip, which replaced the Sorcerer in 1983.
One of the largest groups in The Netherlands was the ESGG (Exidy Sorcerer Gebruikers Groep) which published a monthly newsletter in two editions, Dutch and English. They were the largest group for a while in the HCC (Hobby Computer Club) federation. The Dutch company De Broeders Montfort was a major firmware manufacturerer.
The Sorcerer also had a strong following in Australia. This is most likely due to Dick Smith Electronics, being a leading electronics and hobbyist retailer at the time, pushing the Sorcerer quite heavily. The Sorcerer Computer Users group of Australia (or SCUA) actively supported the Sorcerer long after Exidy discontinued it, with RAM upgrades, speed boosts, the "80 column card", and even a replacement monitor program, SCUAMON.
The history of the Sorcerer has interesting parallels with Exidy's competition's attempts to build a home computer, Bally's various attempts at making a "real" machine out of the Astrocade. It is particularly interesting that while the Astrocade (and Datamax UV-1) had limited text capabilities but excellent graphics, the Sorcerer instead had excellent text and only "usable" graphics.
[edit] Description
The Sorcerer was an interesting combination of parts from a standard S-100 bus machine, combined with their custom display circuitry. The machine included the Zilog Z80 and various bus features needed to run the CP/M operating system, but placed them inside a "closed" box with a built-in keyboard similar to machines like the Atari 8-bit family and Commodore 64. The rest of the S-100 expansion capabilities were instead to be provided in an external box.
Even the basic machine was usable on its own, an advantage over other S-100 machines. It included a small ROM containing a simple monitor program which allowed the machine to be controlled at the machine language level, as well as load programs from cassette tape or cartridges. The cartridges, known as ROM PACs in Exidy-speak, were actually eight-track tape cases containing a circuit board and edge connector to interface with the Sorcerer.
With additional hardware plugged into the S-100 bus (actually a dual-50-pin connector on the back of the machine) the Sorcerer could directly support floppy disks, and boot from them into CP/M (without which the disks were not operable). Another expansion option was a large external cage which included a full set of S-100 slots, allowing the Sorcerer to be use like a "full" S-100 machine. Still another option combined the floppies, expansion chassis and a small monitor into a single large-ish box.
Graphics on the Sorcerer sound impressive, with a resolution of 512×240, when most machines of the era supported a maximum of 320×200. These lower resolutions were a side effect of the inability of the video hardware to read the screen data from RAM fast enough; given the slow speed of the machines they would end up spending all of their time driving the display. The key to building a usable system was to reduce the total amount of data, either by reducing the resolution, or by reducing the number of colors.
The Sorcerer instead chose another method entirely, which was not really to have graphics at all. There were 256 characters possible for each screen location. The lower half was fixed in ROM, and contained the usual ASCII character set. The upper half was defined in RAM. This area would be loaded with a default set of graphics at reset, but could be re-defined and used in lieu of pixel-addressable graphics. In fact the machine was actually drawing a 64×30 display (8×8 characters) which was well within the capabilities of the hardware. However this meant that all graphics had to lie within a checkerboard pattern on the screen, and the system was generally less flexible than machines with "real" graphics. In addition, the high resolution was well beyond the capability of the average color TV, a problem they solved by not supporting color. In this respect the Sorcerer was similar to the PET in that it had only "graphics characters" to draw with, but at least on the Sorcerer one could define one's own.
Given these limitations, the quality of the graphics on the Sorcerer was otherwise excellent. Clever use of several characters for each graphic allowed programmers to create smooth motion on the screen, regardless of the character-cell boundaries. A more surprising limitation, given the machine's genesis, is the lack of sound output. Enterprising developers then standardized on attaching a speaker to two pins of the parallel port, which users were expected to supply.
Another item of note on the machine was the excellent keyboard, which suggested it was more of an "upscale" machine competing in the S-100 world than the average home computer. It was well built with considerable "throw" to the keys, and also included a numeric keypad. The keyboard included a custom "Graphics" key, which allowed easy entry of the extended character set, without having to overload the Control key, the more common solution on other machines.
A Standard BASIC cartridge was included with the machine, this was essentially the common Microsoft BASIC already widely used in the CP/M world, but Exidy added a number of one-stroke commands that allowed you to type in common instructions, like PRINT with a single keystroke (much like the Commodore BASIC substitution of '?' for the 'PRINT' statement). The machine included sound in/out ports on the back that could be attached to a cassette tape recorder, so BASIC could load and save programs to tape without needing a disk drive. An Extended BASIC cartridge requiring 16 KB was also advertised, but it is unclear if this was actually available; Extended BASIC from Microsoft was available on cassette. Another popular cartridge was the Word Processor PAC which contained a version of the early word processor program Spellbinder. A constant ROM fault in the wordprocessor PAC was a printer status switch setting for the printer, but most people learned about it and turned it off early in their power-on. The Montfort Brothers made an Eprom PAC with a rechargeable battery inside and 16 KB RAM with an external write-protect switch. Thus bootable software could be uploaded to the pack and kept for a longer period.
[edit] Specifications
- CPU: Zilog Z80, 2.106 MHz (later 4 MHz)
- RAM: 4 kB, expandable to 48 kB. larger sizes came standard in later runs
- ROM: 4 kB, cartridges could include 4 to 16 kB
- Video: 64×30 character display, monochrome
- Sound: none (external additions possible)
- Ports: composite video, Centronics parallel, RS-232, sound in/out for cassette use, 50 pin ribbon connector including the S-100 bus.
