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And again the doors of the virtual historical museum are wide open. Today we have to get acquainted with the computer Processor Technology Sol-20 Terminal Computer , which was born in June 1976. About how he got the name Sol-20, high-tech historians have two versions. Either the biblical Book of Wisdom of Solomon inspired the name of its creators, or the computer was named after Les Solomon, editor of Popular Electronics magazine , on whose pages the first review of the novelty appeared.
First, technical details and some facts about Sol-20. "Lyrics" is left for dessert. This computer was based on the Intel 8080 processor, the clock frequency of which was 2 megahertz. RAM: 1 kilobyte, but it was possible to increase to sixty-four. The supported display resolution was 64 x 16 and allowed to display only textual information. Accordingly, the game only in the form of pseudographics. That is, graphics, simulated text characters.
Extensions: S-100 bus with five slots. Ports: parallel, serial and for a cassette recorder. As many have already guessed, audio tapes were used as a drive. But Sol-20 could be equipped with a novelty for those times: a floppy, that is, a drive for magnetic disks. Most likely, each of our readers understands what is at stake. And, nevertheless, we will bring clarity to those who joined the computer wisdom only recently.
The fact that in the English-speaking world is called "floppy disks", we have been called "diskettes". Then both names were mixed and Russian-language use. Older people, as a rule, spoke “floppy”; younger users sometimes spoke English “floppy disk”. Then the floppy disks finally gave way to flash drives and there was nothing to talk about in the absence of the very subject of the conversation.
Let's return to Sol-20. It was created by renowned electronics engineer Lee Felsenstein, who led the Home Brew Computer Club. You can translate it roughly, as the "Club homemade computers." Five years later, it was Felzenstein who created the famous computer Osborne 1, about which many could hear something.
In the form of a finished product, it cost 2,129 US dollars. It was possible to purchase it in the form of an assembly kit, a kind of "designer" for $ 995. I must say that in those days computers were often sold in such a “semi-ready” form. The place of the Sol-20 operating system was occupied by the interpreter of the programming language BASIC. He also worked under the control of the real CP / M operating system developed specifically for eight-bit (eight-bit) computers.
About ten thousand of these electronic computers have been produced in the entire history. Yes, in those days large numbers of newspapers, magazines and books were published, but not computers. About any hundreds of millions and billions of devices (with which today no one will be surprised anymore) could not even speak.
As often happened in those days, Sol-20 exceeded the expectations of its creators. We developed it as a terminal designed to interact with other devices, but over time it was transformed into a full-fledged computer based on the S-100 bus.
At first there was a Sol-PC, a single printed circuit board without a case and a power supply. It was sold for $ 475 as an assembly kit. In the assembled state, it cost the buyer $ 745.
This board later became the motherboard of the Sol-10 and Sol-20 computers, which already acquired the case and the power supply, and even the keyboard. Sol-10 was different from Sol-20 in the absence of an expansion backplane. Its keyboard was simpler, and the power supply less powerful. It cost, respectively, about $ 200 cheaper. History is silent about how much Sol-10 was sold. Most likely, very few or none at all, but articles and advertising, even in 1977, speak of this model. One way or another, but all the laurels went to the G20.
Sol is known for being one of the first personal computers with an integrated keyboard. Sol-20 is notable for departing from the original “rudeness” characteristic of the design of the first computers. Here we already see the stylish blue metal keyboard case and wooden side panels. Not so much in the history of mankind there were mass computers containing parts made of wood. However, a couple of models can be called (besides Sol): NorthStar Horizon and Ohio Scientific C2-4P.
Expansion cards were located in the Sol-20 horizontally and too close to each other. The cramp could be compared only with that observed in public transport during peak hours. In order to replace one card, it was sometimes necessary to take out the next one, since their components sometimes came after each other like a puzzle.
Why the developers did not make the system unit larger? The answer to this question is simple and clear to everyone: for reasons of economy. And it was connected with wooden side panels. It was in this size that they were cheaper. Why, it is not specified. It can be assumed that these were some standard configurations of plates, and in order to make the body larger, you would have to order according to your own drawings. And finished products, as a rule, are cheaper than those that are made to order.
As noted above, a total of about ten thousand Sol were sold. Most of them came in Sol-20. Somewhere five thousand sets for assembly and five thousand ready computers. That is, approximately equally. Half of the buyers preferred to save, the second decided not to bother with self-assembly of a computer and to overpay for the fact that this work was done for them by experts ... I must say that it was a significant overpayment. Although the assembly kit cost more than half the price, it was quite risky to buy it: it could never make money, and there was no money back.
As in all ancient personal computers, a tape cassette served as a drive, and a tape recorder, respectively, acted as a drive. Cheap drive, which is in great abundance then present in the market. In Sol, they even integrated an interface for connecting a tape recorder. I must say that the tape recorder was a fairly slow drive, and the information was not always correctly loaded or saved. But cheap and easy!
For those who wanted a more reliable and more up-to-date alternative, which would not impress current users either. In addition, it was possible to purchase the Helios II Disk Memory System, a drive (floppy disk drive) for truly gigantic, another eight-inch floppy disks (floppy disks) compatible with Sol-20. And here, too, it was possible to save money and pay for it (in the form of an assembly kit) “only” 1 thousand 895 US dollars. Or lay out 2 thousand 295 US dollars for the assembled, "ready to use" drive.
Do I need to further explain why in those days, many preferred slow and not very reliable tape recorders? We believe that the prices quoted are sufficient to make it extremely clear why users were not in a hurry to take advantage of the supernovae technology.
Let us dwell a bit near the exposition of the virtual museum, where the floppy disk drive Helios II is located. It worked simultaneously with two eight-diskettes Persci diskettes, with a capacity of 384 kilobytes each. This drive stood out from among themselves. He had a single motor that simultaneously rotates both floppy disks.
His only linear positioning servo simultaneously moved the heads for both diskettes. The drive and the head electromechanically separated one diskette from another. By pressing a special button you could get your floppy disk back. The principle of inserting a floppy disk was electromechanical. The drive allowed copying data from one diskette to another without using a computer processor. That is, the drive acted as a kind of “digital carbon copy”.
Due to the extreme complexity of its design, Helios II Disk Memory was unstable and periodically required re-calibration. The version of Helios II model 4. The “Four” already supported two “double disks”, that is, four floppy disks.
As noted by enthusiasts who remember those years, the glorious era of the computer industry, there was nothing difficult to assemble a Sol-20 computer from the kit for the average amateur geek. "Some week and it works." Of course, provided that everything was assembled correctly. The golden age (more precisely, the golden decade) in the history of personal computers! Even then, in those modest “designers”, a new image of our civilization was reflected, visible only to a few, only to those who sincerely fell in love with high technology when they had nothing to attract the ordinary user.
Source: Oldcomputers.net
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