Found originally on ebay at a little’ too high price tag but – after contacting the seller when auction expired – I could get an agreement on a more reasonable price (although not negligible, however) aligned to technical and sentimental quality and the overall conservation status of the object, adding this wonderful Sharp MZ-700 to my collection.
Sure, it is risky to treat a purchase outside of the protections of ebay and Paypal, with a complete stranger who could grab the loot and disappear in the depths of the Net, but the experience and intuition in these cases, help a lot. However, I must say that, in the context of the retrocomputing fans , there is a sense of belonging and fairness that everybody shares’ , usually. At least I have not had any unpleasant surprises so far. 🙂
Returning to the subject of this entry, we speak about an original personal computer, produced by the creative and unconventional Sharp, who never hesitated to propose technical and aesthetic solutions in total autonomy, earning the esteem and respect of professional and home computing enthusiasts, and contributing to the evolution of personal computing.
The computer that I recently attached to my collection, the Sharp MZ-700, belongs to the MZ family of the brilliant Japanese manufacturer, stood out for the most famous MZ-80, from which the family MZ-700 derives, inheriting some features (plus a reasonable level of backwards compatibility), adding more features of theirs, according with the times.
The MZ-700 lineup was released in Japan at the end of 1982, and joined the rest of the world during the next year.
It is an architecture built around the inevitable Zilog Z80, already widely used in other computers of that period. The graphics were a bit’ poor, especially when compared with the antagonists of the time. In fact it did not have an architecture oriented towards advanced animation and entertainment, as was the case instead for the Commodore 64, undisputed protagonist of the 80s. The graphic did not count on a dedicated chip, but it was directly managed by the processor, with a palette of only eight colors, 256 graphic characters resident in ROM, a resolution of 80 x 50 pixel, capable of displaying a text mode with 40 characters on 25 lines.
The audio section was entrusted to a single channel, extended over three octaves. As proposed on the Sinclair ZX Spectrum, Sharp MZ-700 also possessed an internal speaker, from which the computer issued their own sounds.
The video outputs then conveyed only the image information, and were handled in a very flexible way. In addition to the classical RF output (switchable on choice between B/W or color), There was a composite video output dedicated to monochrome monitors, and an RGB/composite output of great quality, that nowadays lends itself perfectly to the links on the SCART socket.
On the machine back was also possible to connect an external tape recorder, and they also included a serial port, an expansion port for interfacing Z80 to external peripherals, an input port for the joystick, the RESET button, a connector for power grounding, the power mains input, directly connected to the internal power supply and the power switch.
Sharp MZ-700 was able to count on a wide range of expansions and external devices, that over time provided it with external floppy drive, Barcode readers, printers, and graphics adapters for the advanced 80 columns mode, included as standard in the top model of the series.
The line MZ-700 benefited from some devices included as a computer embedded part, such as the tape recorder and micro four-color plotter. The combinations of these devices led to differentiate their offerings in four distinct models: MZ-711, MZ-721, MZ-731 (The model I own), MZ-780. The family MZ-700 was subsequently evolved and replaced by MZ-800, But that turned out to be not backward compatible.
While almost all the competitors at the time proposed the BASIC as operating system for its own models, while SEGA required the insertion of a cartridge for the operation of their own SC-3000, Sharp MZ-700 proposed an halfway solution, that is, implementation of a very simple and basic bootstrap, forerunner of the modern BIOS/EFI solutions, simply called Monitor, with a handful of commands by which a language or an operating system could load from tape or floppy. Indeed in the absence of specific software, Sharp MZ-700 could do so little.
A very original feature of this computer was that, in the presence of internal or external printer plotter, allowed to switch the video output on paper, so to ensure a basic user interaction even in the absence of monitors. Nothing short of brilliant!