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Microcomputers

Over this same time frame, the microcomputer revolution was starting.

The first commercially available microprocessor, the Intel 4004, which was originally designed for a calculator from Busicom, and which therefore was not permitted to be used in calculators by anyone else, was announced on November 15, 1971. It took the 8-bit Intel 8008, announced in April, 1972, however, to make the idea of inexpensive computers seem like an imminent possibility.

The very first self-contained microcomputer system appears to have been the Q1, which used the 8008, and for which a PL/I "compiler-interpreter" was available. It is said to have been primarily aimed at applications such as order entry, although a brochure for its successor, the Z-80 based Q1/Lite, suggested it was a general-purpose machine. This computer was first delivered in December 1972.

Not visible in the image is its display, a one-line 80-character LED display.

The September 1973 issue of Radio-Electronics featured an article by Don Lancaster on how to build an inexpensive video terminal; the design was called the "TV Typewriter", and such a device would potentially be a handy item for someone with some type of computer, and without ready access to, say, an ASR 33 Teletype through surplus channels. And there were already used PDP-8 computers kicking around.

The cover of the July 1974 issue of Radio-Electronics magazine, shown at right, showed a computer you could build at home! It was the Mark 8, based on the Intel 8008 microprocessor.

The Intel 8008 fit in an 18-pin package, as small as that containing many ordinary integrated circuits. It used a single 8-bit bus for data and (in two parts) addresses. As there were two status bits included with the most significant byte of the address, it could only be connected to a maximum of 16K bytes of memory, not 64K, although at the time memory was too expensive for this to be much of a limitation. Initially, however, the support chips for the 8008 were in limited supply.

The Intel 8008 chip itself had been available from April 1972.

The Mark 8 computer based on the 8008 did not make much of a splash at the time.


The same was not the case, though, with the January 1975 issue of Popular Electronics. That was the one that had the Altair 8800 on the cover, shown at left, based on the Intel 8080 chip, which had been available since April 1974. This chip was in a 40-pin package, a size in which many other 8-bit microprocessors were also packaged. It had a full 16-bit address bus along with an 8-bit data bus.

Magazines hit store shelves before their printed cover dates; according to Wikipedia, this magazine was distributed in November 1974. That can be said to be when the microcomputer revolution started in earnest.



The pace of events from then on was rapid.

In June 1976, Texas Instruments produced one of the first 16-bit microprocessors, the TMS 9900. It had an architecture very similar to that of the PDP-11, although there were also important differences. One feature that limited its speed, but allowed the circuitry for a 16-bit microprocessor to fit on a single die at the time, was that its sixteen general registers were all in main memory. A workspace pointer register indicated where they were in memory, allowing quick context switches for subroutines.

Texas Instruments sold minicomputer-like systems based on this chip, such as the 990/4. Later, they also implemented the architecture in faster but smaller integrated circuits, to make the 990/10, a minicomputer version, and they even went on to make the 990/12 which added floating-point in hardware. When, much later, they made a home computer using this chip, the 99/4, its performance was significantly reduced, as it used a very limited amount of actual RAM, and instead used a slower type of memory for many of the functions that RAM would normally be used for in a microcomputer system.

December 1976 marks the first shipment of the Processor Technology SOL-20 computer (announced in the July 1976 issue of Popular Electronics). It was designed to be easier to use than an Altair or an IMSAI (a clone of the Altair, built to a higher standard of production quality); instead of a box with lights and switches, it had a keyboard in it, and hooked up to a video monitor. The regulatory hurdles to including an RF modulator for use with one's TV set hadn't quite been sorted out at that time just yet.

Here is an image of the IMSAI 8080, and of another similar copy of the Altair, this one being the one by Ithaca Intersystems:

and one of the Processor Technology SOL-20:

It was moderately popular with early adopters. However, it was in the next year that the floodgates opened, as 1977 was the year of the original Commodore PET computer, the first Radio Shack TRS-80, and the Apple II. The Apple II and the Commodore PET were both introduced at the first West Coast Computer Faire, which opened on April 16, 1977. The TRS-80 was announced on August 3, 1977.

Here are pictures of these three computers, from early advertisements for them.

The original Commodore PET was the only one of these three that did not have a normal typewriter keyboard; this was corrected in their later machines, and it was noted at the time that this was a more serious issue than some might have thought. This affected how people reacted to the keyboard of the IBM PCjr much later.

The Exidy Sorcerer, also identified with the early days of computers, dates from April, 1978, and so it came after these three famous computers.

This was also the year when North Star offered a 5 1/4" floppy disk drive system, admittedly one using more expensive and harder-to-find hard-sectored floppy disks, for S-100 bus computers. It included North Star DOS, a simple operating system with two-letter commands.


Incidentally, DOS, an acronym for Disk Operating System, was in use long before this, so Microsoft didn't swipe the name from North Star when it came out with PC-DOS for the IBM PC in 1981. The IBM System/360 computer was available in a number of different models with different amounts of processing power, and it could be configured with different amounts of memory. The operating system OS/360 (Operating System/360) was used with larger systems; BOS/360 (Basic Operating System/360) was used with the smallest systems, and initially with all the systems until the other versions of the operating system were completed; there was also TOS/360 (Tape Operating System/360) and DOS/360 (Disk Operating System/360) which were used on most systems not large enough for OS/360. Eventually, other operating systems were developed to support more advanced features such as virtual memory (what we now know as a swap file) and virtualization.

The power and low cost of microcomputers had not gone unnoticed by small businesses. So not all microcomputers were designed for use in the home; some were instead designed for use by businesses. Many of those used either an Intel 8080 processor, or the Zilog Z-80, which was compatible with the Intel 8080 but included additional features as well, and ran the CP/M operating system. Radio Shack produced the Radio Shack Model II computer, aimed at business users, which had a different operating system which was arguably better than CP/M.

Three examples of CP/M-based computers are illustrated below, the Kaypro II portable computer, which had a 9-inch screen with 80 columns, to compete with the Osborne I which had a smaller 56-column screen, the Intertec Superbrain computer, and the Toshiba T200. And then a Radio Shack TRS-80 Model II is also shown.

Incidentally, if the image of the Intertec Superbrain computer above looks somehow familiar, you are not imagining things. Here is an image of the ADDS Consul terminal:

The Intel 8086 chip was released in the middle of 1978. This powerful 16-bit microprocessor could address up to one megabyte of memory, since the contents of its 16-bit segment registers were shifted left by four bits before being added to the 16-bit addresses in instructions to form physical memory addresses. (Since the segment registers could be loaded by user programs, the virtual address space - or, more precisely, the address space seen by the programmer; swap files and virtual memory came along with Windows and the 80286 - was also one megabyte in size.) Before the IBM PC, some other computer systems based on the 8086 were sold, but they tended to be expensive.

The Atari 400 and 800 were introduced in January, 1979. The less expensive model, the 400, had a membrane for a keyboard; these were the first home computers of the generation that followed the three home computers introduced in 1977.

November 1979 marked the introduction of the TI 99/4 home computer. An image of the slightly revised later model, the TI 99/4A, is shown at left.

It was based on the TMS 9900 microprocessor, introduced in 1975, a 16-bit microprocessor originally in a 64-pin ceramic package. It was used to make the TI 990/4 computer, which replaced the TI 980 minicomputer made by Texas Instruments. The image below

shows the TI 990/4 on the left, and the TI 990/10 on the right; the TI 990/10, although compatible with the TI 990/4, did not use the 9900 chip, but instead was implemented in LSI for higher performance, so it was a minicomputer rather than a microcomputer.

Also in 1979, Texas Instruments made available a single-board development kit for educational use, the TI 990/189, shown in this image:

The 9900 was one of the earliest 16-bit microprocessors, if not the earliest. It achieved this by reducing the required number of transistors, and thus the die size, by using memory to store its registers. One on-chip register, the Workspace Pointer, pointed to the area in memory containing the 16 registers; this allowed rapid context switching, even if it meant the processor was otherwise slower. Also, its design made no provision for addressing more than 64 kilobytes of RAM, so in this respect it was similar to an 8-bit processor.


The keypad provided on the 990/189 board, while it used plain buttons, and a different faceplate, was molded from the same tooling as used to make the front half of the case of the TI 59 and TI 58 programmable calculators, as can be seen by comparing the unit to the photo of a TI 59 on the right.

Although the 9900, therefore, might not have been quite as powerful as the Motorola 68000, it still worked on 16-bit numbers and was therefore faster and more powerful than an 8-bit chip would normally be. This should have made the TI 99/4 a very important and exciting computer.

That, however, was not the case; instead, it compared unfavorably even with most of the competing 8-bit processors.


There were three basic flaws which beset the TI-99/4:

The latter flaw, not directly visible to the user, may have been due to the various support chips available being designed for 8-bit microprocessors, rather than the intent of not competing with the 990/4. Of course, they had chips with which to build the 990/4, but had the 99/4 been built that way, it would have been much more expensive, and not a home computer any more.

The Sinclair ZX-80 was announced on January 29, 1980; it was a major stride forwards in making a computer of some sort widely affordable; its successor, the Sinclair ZX-81 from March 1981 was considerably more widely available in the form of the Timex-Sinclair 1000, and also considerably more successful. This displayed text and graphics on a TV set, but only in black and white, and the keyboard was a small membrane surface with blister bumps, so compromises were made to attain its very low price.

In June, 1980, IBM announced the Displaywriter, a word processor that was powered by the Intel 8086 chip; it used 8-inch floppy disks, and some companies released software for it that let it perform computing functions instead of only word processing. It was considerably more expensive than the IBM PC, based on the version of that chip with an 8-bit data bus, the 8088, would later be, but then, that is normal in the computer business, and indeed the IBM PC was a project done in great secrecy by a small, independent group, so the Office Products Division, of which the Displaywriter was a product, would not even have been aware of it. The Displaywriter is pictured below:

It was made with the same build quality as IBM's mainframe products; the keyboard, for example, was the same beam spring type as found in such terminals as the 3277 Display Station, or in the IBM 5100 Portable Computer, as opposed to the less expensive buckling spring keyboard used in the IBM PC.

Incidentally, however, the buckling spring keyboard was not developed for the IBM PC. Just as it used a monitor with the same styling (if not the exact same monitor) as the Displaywriter, the buckling spring keyboard had been previously developed for another IBM product, the IBM System/23 Datacenter processor. That appears to have been a replacement or successor to the 5110-3 processor from the IBM 5120 system.

The TRS-80 color computer, which used the advanced Motorola 6809 processor, an 8-bit processor with a multiply instruction, was introduced in September, 1980, another entry in the second generation of 8-bit home computers.

The Commodore VIC-20 began life in Japan in 1980, and was introduced to the rest of the world in 1981; it too made computers more affordable, but it had a "real" keyboard and it displayed text and graphics in color, admittedly with only 22 characters per line of text, on the TV set to which it was connected.

And then came the IBM PC, which was announced on August 12, 1981.

When it was announced, various brands of 8080 and Z-80 based computers running the CP/M operating system were well established in the market. While many systems using the same CP/M operating system were made by different manufacturers, they weren't fully compatible with each other; for example, they used different floppy disk formats. One of the most popular CP/M based computers, the Osborne I, had an even more serious incompatibility, it had a display that was 56 characters wide instead of 80 characters wide.

This made buying software for these computers more complicated.

As the IBM Personal Computer used a different processor, one with a 16-bit architecture instead of an 8-bit architecture, of course it wasn't compatible with those machines. However, its operating system, PC-DOS, very closely resembled CP/M in its repertoire of commands. One improvement was that the command to copy a file from one disk to another was COPY in PC-DOS, whereas it was PIP in CP/M.

PIP stood for Peripheral Interchange Program; one can't criticize Microsoft too severely for copying the commands of CP/M without noting that Digital Research copied their commands... which PIP served to indicate as the 'smoking gun'... from OS/8, an operating system for the PDP-8 system produced by the Digital Equipment Corporation.

Also, the 8086 architecture was influenced by that of Intel's earlier product, the 8080, and this made it easier for companies that were selling software for CP/M-based microprocessors to make versions for the IBM PC. Thus, it was not long after the introduction of the IBM PC that one could get dBase II for it and Wordstar for it, for example.

Some people claim that the IBM name was the only thing that made the IBM Personal Computer an immediate and huge success. I do think that it helped, but I also think that this view ignores the real foundation for that computer's success.

The IBM name did mean that people had confidence that this computer would continue to be available for a while, and so a good selection of software would continue to be available for it. This is very important, since for most users, the available pool of software is what determines the value of a computer. Some might decry the fact that computer buyers have a "herd mentality", only considering the most popular systems, but this is why they are acting rationally in this respect. And while CP/M based systems often had varying disk formats, the IBM PC defined one single standard, making it easy to get software.

As noted, it helped that the IBM PC resembled the previous industry standard, the CP/M based microcomputer, enough to make switching to it, and developing software for it, easier.

While the IBM PC was certainly more expensive than many other computers sold at the time, a number of CP/M-based microcomputers were equally expensive.

And while CP/M-based microcomputers either had a 64K memory size, or a 128K memory size achieved through adding special hardware to switch memory banks, the IBM PC could be expanded to 640K of memory. This, in itself, made it significantly more powerful; the fact that its CPU was a 16-bit processor rather than an 8-bit processor, of course, also gave it considerably increased power.

Although the 8088 chip in the IBM PC was a 5 MHz part, the computer used a 4.77 MHz clock to simplify the design of its video display circuitry. The IBM PC was expensive enough so that its initial success was with business users, although, as noted, it was still a bargain compared to many CP/M systems designed for business use that were equally expensive, but the CGA display card for it produced an output compatible with North American NTSC television standards, and it was available without floppy disk drives, as it had a port on the back for a special cassette tape drive (which still used the standard Philips audio Compact Cassette); thus, its design did have many aspects of that of a computer for personal home use.

In fact, some reviewers criticized the IBM PC because, in their opinion, IBM hadn't made up its mind who the computer was for; it was a computer with build quality adequate for the office, but not designed to the same standards as some IBM equipment the way the Displaywriter was, which would have driven up manufacturing costs, and hence the retail price of the computer, to a significant extent, and it could be purchased in a very basic configuration suitable primarily for home use. IBM's intent seems to have been to allow the market to make as much use as possible of the IBM PC, to help ensure its success and broad adoption.


The IBM PC was a spectacular success for IBM, even if, ultimately, the popularity of less expensive compatible computers led to Microsoft and Intel ending up making more money from its success than IBM. Before it left the consumer PC business on May 1st, 2005, selling it off to Lenovo, it had attempted to deal with the issue through the introduction of Personal System/2, announced on April 2, 1987, which in addition to moving to the 3 1/2" floppy disk from the 5 1/4" floppy disk, and introducing a smaller keyboard connector, as well as a similar mouse connector (previously, mice had to be connected via a serial port), introduced the Micro Channel Adapter bus for which a higher rate of royalties would be charged as it embodied a considerable amount of new technology.

A Personal System/2 Model 50 is pictured at right.

The market, however, saw little reason to subscribe to a more proprietary standard which did not offer obvious advantages. OS/2 was announced shortly before the PS/2, but Windows was already in existence, and IBM had allowed Microsoft to be involved with OS/2 which it abandoned in favor of Windows NT. Had IBM, instead of Microsoft, been the company that developed the standard GUI for the IBM PC, of course, it would have succeeded in diverting the gravy train its way. However, to develop Windows, Microsoft had to license key interface elements from Apple, and either Apple or IBM might have balked at a similar relationship between those two companies instead.

The IBM PC was designed by a team of twelve engineers and one manager, working independently from the rest of IBM; this was not the usual way in which IBM products were designed, but it was realized that in order for the IBM PC to succeed in the highly competitive microcomputer field, it could not be held back by fears that it might undercut other IBM products. And perhaps I might also add "for example" and "among other things".

It was noted above that the Control Data 6600 was announced on August 23, 1963. On August 28, 1963, Thomas J. Watson Jr. sent a famous memo to several of the top managers at IBM in which he noted the need for a meeting to discuss how a much smaller company could have come out with the world's fastest computer instead of IBM having done so, particularly as the facility at which it was developed had a staff of 34 people - one of whom was the janitor, in contrast with IBM's "own vast development activities".

Seymour Cray is said to have quipped that in making this contrast, "It seems Mr. Watson has answered his own question".

Given the nature of the effort to design the IBM PC, it might fairly be said that at least in that case IBM demonstrated that it had learned its lesson, even if that lesson may not have been applied where it counted.

But while IBM may have failed to maintain control of the IBM PC platform, it was certainly right in realizing that the microcomputler field was going to be of vast importance. So they had applied their lesson where the stakes were highest, and the failure was later and in another area.


The Commodore 64 was introduced in January 1982; with 64 K of memory, it competed with machines like the Apple II and the TRS-80, but at a lower price; it also competed with the Atari 400 and 800, and the Radio Shack Color Computer from 1980, which was based on Motorola's 6809 processor that featured multiplication in hardware. Like the Commodore PET and VIC-20, and the Apple II, and the Atari 400 and 800 from 1979, it was based on the MOS Technology 6502; this chip was introduced after the Motorola 6800, and intended as a lower-cost competitor to it. Commodore used so many 6502 chips that it had purchased MOS Technology in 1976. The Commodore 64 was the successor to the VIC-20 from 1980, and had the same general shape as it, if a different color scheme.

The Intel 80286 chip was introduced on February 1, 1982. It offered a "protected mode" of operation which allowed the use of 24-bit addressing. The original IBM System/360 computer had the same size of address, allowing access to 16 megabytes of main memory. It lacked the "virtual real mode" feature introduced on the 80386, however, and that meant there was no practical way to use the chip for an advanced operating system that could both use the increased amount of memory and still use all the popular software written to run on the IBM PC with the original addressing conventions of the 8086 architecture.

July 1982 is when the Timex-Sinclair 1000 computer was introduced, a home computer for those of modest means.

November 1982 is when the Compaq Portable was announced, the first third-party computer that was fully compatible with the IBM PC. This required a great effort on their part to write a BIOS for their computer that was compatible with that of the IBM PC without being copied from it in violation of copyright; some later clone makers were not careful enough in dealing with this issue. "Fully-compatible" clones of the IBM PC, however, were actually incompatible in one respect; they lacked a copy of Microsoft's cassette BASIC for the IBM PC in ROM. However, this was only used by the version of BASICA that came with PC-DOS; the version of the same operating system sold by Microsoft to owners of computers resembling the IBM PC, MS-DOS, came with GW-BASIC instead of BASICA, which was an equivalent interpreter, but not dependent on the ROM copy of a simpler version of BASIC.

MS-DOS was available in versions for 8086-based computers that were not completely compatible with the IBM PC, but as this led to problems in buying software for them similar to what existed in the CP/M era, the success of these machines was limited.

1984 is memorable for two advances. In that year, IBM brought out a larger model of their personal computer, the IBM Personal Computer AT, which used the more powerful 80286 processor. A far more influential event, though, was the introduction by Apple of the Macintosh computer.

The Apple Lisa computer had been introduced in January, 1983. Like the Macintosh, it had a graphical user interface, so when the Macintosh came out, it did not come as a total shock. As well, an article had appeared in Scientific American previously about the work on graphical user interfaces for computers at Xerox PARC, so it was generally known that such interfaces were possible for computers.

The Lisa is pictured below, first in its original form, and then its appearance after it was changed to use standard 3 1/2" disks is shown.

Originally, it used modified 5 1/4" disks, which had two openings through which the magnetic surface could be accessed at the sides, instead of one at the end inserted into the computer.

The Macintosh, pictured at left, however, was far less expensive, and was thus something home users could consider. Both of these computers were based on the Motorola 68000 processor, also used for early Apollo workstations, the Fortune Systems 32:16 computer, and a laboratory data collection computer from IBM, all of which were quite expensive systems.

While the original Macintosh was quite limited by the fact that it only had 128 kilobytes of memory, this was soon remedied by the Macintosh Plus, which had 512 k of RAM instead.


Motorola eventually made the 68008 chip, a version of the 68000 that had an external 8-bit bus available, but too late for it to have been used in the IBM PC.

However, that was used in the Sinclair QL computer, announced on January 12, 1984.

The Sinclair QL, shown at right, unlike the Macintosh, did not have a graphical user interface, although it did interact with the user by means of menus. As an inexpensive computer providing access to the power of the 68000 architecture, it was a very exciting product at the time, but its success was fatally hampered by two instances of one basic flaw. Instead of coming with floppy disk drives, it used a non-standard form of tape cartridge, and instead of offering a hard disk as an option, the option for larger storage was a solid state disk based on wafer-scale technology... which never materialized. Prospective purchasers, especially those outside of the United Kingdom, were naturally skeptical about the prospects of there being the needed support infrastructure to make the computer genuinely useful.

The Macintosh was famously announced with a television commercial that aired during the Super Bowl, which is the culminating game of American football, on January 22, 1984.


Another very important event happened in 1984: the first Phoenix BIOS became available. This enabled many companies without the resources to develop their own legal and compatible BIOS, to start making computers fully compatible with the IBM PC. Unlike the Compaq, which was sold at a premium price, these were often sold at lower prices, reflecting their new status as generic commodity products.

And soon after, the Award BIOS was available as a competitor to the Phoenix BIOS, and the government of the Republic of China (located on the island of Taiwan, by the name of which it is better known) even arranged to have a BIOS written for the benefit of that country's PC manufacturers, and then came the American Megatrends BIOS, later versions of which are found on today's motherboards.

Thus, the floodgates were opened at this point, and many more people had the opportunity to own a computer that could run the same software as the IBM PC. The cover of the October 14, 1986 issue of PC Magazine, shown at right, illustrates the situation that eventually arose, if with some exaggeration for effect.


Another notable computer introduction from 1984 was that of the IBM PCjr. This was an attempt by IBM to make a lower-priced computer that would address the home market. It came with PC-DOS 2.1 which included some modifications to support this computer.

It had two cartridge ports below the standard 5 1/4" floppy disk drive in the case.

Naturally, it had some limitations of expandability compared to the original IBM PC. This would soon become a very good reason not to buy one, when the inexpensive imitations of the full IBM PC started to come out. But one reason advanced for not considering this computer was specious.

The photo shows the original keyboard of the IBM PCjr, with push-button keys. This was condemned as not being a "real" keyboard, and the example of the original Commodore PET was often cited.

The outcry was so loud that IBM eventually provided all the original purchasers of the computer with a revised keyboard with full size keys.

Computer columnists praised IBM for this remedial action, and praised the new keyboard for its improved feel.

I remember comparing the two keyboards in an IBM storefront at the time, and in my opinion, the tactile characteristics of the two keyboards were identical. Unlike the keyboard of the original Commodore PET, the original IBM PCjr had keys which had the same spacing and position as those of any other normal typewriter-style keyboard.

So, yes, you could touch-type on the original IBM PCjr keyboard.

Even so, why did IBM risk what ended up happening by not making the keyboard of the IBM PCjr conventional in every way? Was it just to keep it out of offices, so that it wouldn't compete with the more expensive real thing?

No. There was a reason behind the keyboard of the IBM PCjr, a reason which drew inspiration from a much more expensive IBM product, the IBM 2250 graphics terminal. The photograph at left of one example of that item came originally from an advertisement for Sikorsky Aviation, a maker of transport helicopters.

This is a type of graphics terminal that allowed moving graphic displays to be provided with relatively modest amounts of computer power. It had a cathode ray tube as its display element, but that tube worked like the CRT in an oscilliscope rather than the CRT in a television set. That is, instead of the electron beam in the tube tracing out a raster, a pattern of lines that covered the whole screen, with images being placed on the screen by varying the intensity of the electron beam, and hence the brightness of the current point on the screen, over time, instead the beam was directed to move over the screen along the lines of the image to be drawn, just as a pen would move on a sheet of paper when drawing an outline picture.

Terminals of this general type were usually provided with light pens. This input device served to indicate a point on the screen; they contained a lens and a photodiode or other device sensitive to light, and so a point on the screen was indicated by an electrical pulse coming from the light pen when the electron beam was at that point on the screen.

Light pens could also be used with raster displays; in the case of a vector display, to use a light pen to indicate a point in the blank part of the screen required the terminal to draw a cursor on the screen that followed the light pen from some starting point on which there was always something drawn.

Note, in the lower left corner of the image, to the left of a conventional terminal keyboard in the typewriter style, a square keyboard of round buttons, with 32 buttons in a 6 by 6 array with the corners omitted.

There was plenty of space between the buttons for a reason: so that a sheet of cardboard or plastic with holes cut out for the keys could have legends written or printed on it, so that the keyboard overlay could be used with programs that made use of the display. The top of such a sheet could have notches to indicate which sheet was placed on the keyboard, thus allowing it to be used to choose between many more than 32 possibilities.

While the PCjr didn't do the trick with the notches, overlays for its keyboard were made, so that PCjr software could make use of customized keyboard arrangements easily.



The IBM 2250 came in several forms.

The Model 1 was intended to be used with a dedicated IBM System/360 computer; it had the basic operator control panel, from which that System/360 computer could be started up or shut down built right in to it.

The Model 2 and Model 3 were controlled by an IBM 2840 Display Control - Model 1 of that display control for the Model 2 of the 2250, and Model 2 of that display control for the Model 3 of the 2250.

The Model 4 of the 2250 display was attached to an IBM 1130 computer, and the IBM 1130 could be used by itself for computing tasks involving the display, or it could be used to give the terminal more local processing power while it was connected to an IBM System/360 computer.

Control Data, the Digital Equipment Corporation, and Xerox also made terminals of the same general type as the IBM 2250. Much later, the Vectrex home video game, pictured at right, made use of the same principle.


Pictured below is Control Data's 240 series graphics terminal subsystem, also known as GRID, for Graphic Remote Integrated Display.

This image is from an advertising brochure by Control Data for the terminal. There is a high-quality color image on the Internet of what appears to be the same model, working with a light pen on an image of a globe on the screen. That picture even appears on the front cover of the book The Power of Go Tools for some reason; presumably, the language Go is well suited to working with graphics, even if this isn't the hardware it would run on.

The internal processor in this terminal, in the cabinet on the woman's right, is a processor with the same instruction set as the Control Data 160 computer.

The GT40 interactive display from the Digital Equipment Corporation used a smaller model of the PDP-11 to provide it with processing power; an image is shown below.

Also, 1984 saw one of the last exciting developments in the field of 8-bit computing.

Spectravideo came out with a pair of computers with both upper and lower case on their keyboards, still something of a rarity; below is pictured the more expensive model with a keyboard made of regular keys instead of buttons, the SV-328:

The keyboard has a very nice arrangement, and this computer inspired a Microsoft standard for 8-bit computers called MSX. (The Spectravideo, however, wasn't fully conformant with the standard as it was established.)

The MSX standard was most significant in the Japanese market, but some MSX systems were sold worldwide. One MSX computer that was memorable was the Yamaha CX5M, since it included a sound chip with capabilities similar to those of its popular FM-based synthesizers; it is pictured below:

In 1985, Compaq brought out the Compaq Deskpro 386, which used Intel's new 386 microprocessor. This computer was faster and more powerful than an IBM Personal Computer AT, and, with appropriate software, it could make use of more memory. Of course, it was expensive, but as the years went by, prices of systems based on the 80386 chip came down; as well, a compatible chip with a 16-bit external bus, the 80386SX, was offered by Intel starting in 1985, which allowed more affordable systems to use the capabilities that the 80386 offered over the 80286.

The Atari ST was introduced in June, 1985, although there was a delay of a month before it became widely available; it was based on the 68000 computer, and offered a graphical user environment by licensing GEM Desktop from Digital Research. It was considered to be an inexpensive alternative to the Macintosh, and it was also significantly less expensive than the Amiga, although that was partly because it lacked the special graphics chips that distinguished that computer.

However, the Atari ST finally, unlike the Sinclair QL, put the 68000 within the reach of the ordinary computer enthusiast in an unproblematic manner, thus putting an end to the 8-bit era, although, of course, its success was still relatively modest, given the explosion of PC clones that would come in the next year.

The Commodore Amiga was introduced on July 23, 1985: it had a 68000 as its processor, but as that processor, powerful as it was by the standards of the time, was augmented by special graphics and sound chips, the Amiga had multimedia capabilities which were not available on the x86 and Windows platform until years later. Although less expensive than a Macintosh, its success in the market was limited, but it lasted until Motorola stopped making chips with the 680x0 architecture. In fact, after its apparent demise, a German company acquired the rights to the system, and successors to the Amiga are still made by that company and others to this very day, but these are mainly of interest to enthusiasts, however much the machine might deserve to be a mainstream computing alternative on its intrinsic merit.

Of course, "amigo" is the Spanish word for "friend", and amiga is the feminine of that. While the intent behind the name was to present the computer as a friendly computer in as positive a way as possible, one could easily imagine a wag noting that its name designated what a typical computer nerd really wanted and didn't have.

Although the IBM PC included a socket for an 8087 floating-point coprocessor, nether the original Atari ST nor the original Amiga included a socket for the 68881, Motorola's floating-point coprocessor for the 68000.

On September 15, 1986, Apple announced the Apple IIgs; this computer used the WDC 65C816 chip, which had been introduced in 1983. It was a chip that was compatible with the very popular 6502 processor, but unlike that 8-bit chip, it was a 16-bit processor that could switch from operating as a 6502 to operating in its own native 16-bit mode.

In April, 1992, Microsoft offered version 3.1 of their Microsoft Windows software to the world. This allowed people to use their existing 80386-based computers compatible with the standard set by the IBM Personal Computer to enjoy a graphical user interface similar to that of the Macintosh, if not quite as elegant, at a far lower price. One major advance over version 3.0 was the addition of support for the TrueType font standard, licensed from Apple.

There was a Microsoft Windows 1.0, and there were a Microsoft Windows 2.0, and a 3.0 as well, of course. The first version of Microsoft Windows required all the windows that were open to be tiled on the screen, rather than allowing overlapping windows as on the Macintosh and the early Xerox machines that pioneered the GUI, and this was generally seen as a serious limitation by reviewers at the time. Windows 3.0 was promoted by an arrangement that allowed Logitech to include a free copy with every mouse that they sold.

It was Windows 3.1, however, that enjoyed the major success that led to Windows continuing the dominance previously enjoyed by MS-DOS. The major factor usually credited for this is that Windows 3.1 was the first version to include TrueType, a technology licensed from Apple, thus allowing it to be used for preparing attractive documents on laser printers in a convenient fashion, with the ability to see the fonts being used on the computer's screen, just as had been possible on the Macintosh.


A brief note on digital vector fonts might be in order here.

Apple developed the TrueType format, which allowed the curved portions of character outlines to be represented by quadratic spline curves, as an alternative to licensing a digital font format that was already in existence and wide use at the time, Adobe's Type 1 fonts, which used Bezier curves.

The Adobe Type 1 font format, however, was not the first digital font format in existence. One which preceded it was the Ikarus font format, developed by Peter Karow. This format used Archimedian spirals instead of Bézier curves, and thus was less sophisticated than what would come later. This format is still supported by the program Font Master from DTL.

And Donald Knuth devised METAFONT, which instead of describing characters in terms of outlines, described a center line to be drawn with an imaginary pen nib which was also described. This accompanied this TeX typesetting program project.

But the granddaddy of all the electronic outline font formats was devised by Peter Purdy and Ronald McIntosh back in the 1960s for the Linofilm electronic CRT typesetter. This is the one that used the Archimedian spiral as the basic element for building the curved lines in characters, since it was an obvious and mathematically simple line of varying curvature that could substitute for the draftsman's French curve.


On this page, I've focused on the dramatic early days of the microcomputer, when many different companies made their own incompatible computers. Particularly after Windows 3.1 made an adequate GUI available for users of PC-compatible computers (with a video card, and a processor, more advanced, of course, than what the original PC offered), so that the Macintosh wasn't the only alternative if you wanted a GUI, the market largely settled down to multiple makers of similar "clone" PCs, with the only real competition between Intel and the few other chipmakers that were licensed to make x86 processors, such as Cyrix at one time, and AMD today.

But the Macintosh still retained a presence. For a time, Steve Jobs parted ways with Apple, and for a time he was offering his own new computer, the NeXT, which was built around BSD Unix. That computer had a monochrome high-resolution display, on which four gray-scale levels were available, and is pictured below.

Initially, the NeXTcube shipped with a copy of Mathematica, which definitely tempted me to run out and buy one if I could have afforded it!

It might be noted that the NeXT was introduced in 1988. It was not until 1992 that Windows 3.1 was introduced, and not even until 1990 that Windows 3.0 was introduced; at the time, the version of Windows available was Windows/386, which had not yet achieved massive popularity. The Amiga was still a popular and viable platform. So, while the computers descended from the IBM PC were definitely dominant, this dominance had not yet reached the absolute nature that it has today.

At the time he returned to Apple, its market share had sunk to a perilously low level. While he brought about many substantive new features to the Macintosh over time, since something was needed quickly to revive interest, he began with something that many would regard as trivial: a new Macintosh with different visual styling.

Of course, it is the original iMac to which I refer. The initial model, pictured at left, was in a color called "Bondi Blue", after the waters off of Bondi Beach in Australia.

Shortly after, the iMac was available in five colors, Orange, Lime, Strawberry, Blueberry, and Grape, shown in the image at right.

This bought Apple time, and saved it from the brink, but it invited a degree of derision from the PC camp.

Of course, as far back as the days of the original Fat Mac, when you couldn't just easily and cheaply buy a 128K Mac, and then later add memory to bring it up to 512K, and as recently as 2019, where the only Macintosh, the Macintosh Pro, that you could open up and put peripheral boards in was the top-of-the-line one at a price of $5,999, the fact that the Macintosh wasn't a computer you could upgrade yourself outside of very narrow limits, and sold at a significant price premium, left typical PC users scratching their heads.

The closed and restrictive nature of the App Store for the iPhone and iPad, and the appearance that Apple was emphasizing those products, and moving away from the Macintosh, also did not help matters.

There were and are people who are devoted to Apple products, and find PC-derived computers and Android smartphones to be far inferior. But Apple's products seem to be niche products, rather than being for everyone; budget-conscious consumers on the one hand, and technically-oriented enthusiasts who want to have control and freedom on the other both have reason to be less than enthused over Apple's products.

And, yet, how can one offer a premium-quality computing experience without doing much of what Apple is doing?

The fundamental problem, that the availability of third-party software is critical to the value of a computer, which leads to nearly everyone jumping on the bandwagon of the most popular machine, hence eliminating alternatives, doesn't seem to be solvable.

Of course, one other alternative survives in addition to the Macintosh. Linux.

When the Yggdrasil Linux CD became available at the end of 1992, the same year that Windows 3.1 came out, it became possible for ordinary people to actually try Linux for themselves.

Nowadays, of course, there are distributions in CDs on the covers of magazines, and it can be easily downloaded from the Internet. But back then, downloading a large operating system like Linux over a dial-up modem would not bear consideration.

Even more so than the Macintosh, however, Linux is too large a topic for me to adequately discuss here.




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