Single-Chip Processors Have Reached Their Limits
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- April 6, 2022
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This text became as soon as first revealed as “Make case history: the Commodore 64.” It seemed within the March 1985 wretchedness of IEEE Spectrum. A PDF model is on hand on IEEE Xplore. The diagrams and photos of chips, circuit boards, and monitors seemed within the distinctive print model.
Charles Winterble, then director of world engineering for Commodore, gave the poke-ahead for the chip effort, and Charpentier’s team labored pretty independently till both chips be pleased been accomplished in mid-November 1981.
At a assembly with Charpentier and Winterble slack that month, Jack Tramiel, then president of Commodore, determined no longer to proceed with the video sport. As a substitute, he determined, the chips would poke into a 64-kilobyte home computer to be introduced on the User Electronics Verbalize in Las Vegas the 2nd week of January 1982. The computer had yet to be designed, but that became as soon as easily remedied.
In two days, the engineers laid out on paper the machine’s in style architecture. Proper sooner than the new year, they performed 5 working prototypes. In the duration in-between, enough running-machine utility became as soon as copied and rewritten from the VIC-20 to supply passable demonstrations of what the new machine may compose. Following its eager reception on the User Electronics Verbalize, the Commodore 64 became as soon as rushed into production; quantity shipments began in August 1982 and be pleased persisted unabated.
No matter complaints about quality regulate and the industry’s slowest disk force, the Commodore 64 has been an unparalleled success, pushing a choice of its opponents out of the market. A part of the reason of its success is the worth, which keeps falling—from $595 at its introduction to $149 currently, for which the consumer gets graphics and sound equal to or greater than that offered by machines that cost 5 events as noteworthy.
Designing the next gargantuan chips
In the slack 1970s, MOS Expertise became as soon as a successful semiconductor firm; its engineers had designed the popular 6502 microprocessor, and it manufactured several reasonably hundreds of solidly promoting products. Commodore, a West Cruise firm on the time, took over MOS in 1976—causing lots of the MOS engineers to forestall when their stock became as soon as sold at 10 cents on the greenback—but MOS became as soon as allowed to operate pretty autonomously.
In 1979 and 1980, recalls Charpentier, MOS Expertise developed the 6510 microprocessor—a minor revision of the 6502 with a extra enter-output port, the 6526 peripheral controller, hundreds of be taught-easiest memory (ROM) chips, and a 4-kilobit random-procure admission to memory (RAM) chip. At the 2nd, MOS became as soon as supplying equipment to Atari Inc., Traditional Electric Co., Hewlett-Packard Co., and a choice of reasonably hundreds of purchasers, as smartly as to Commodore.
When the choice became as soon as made to originate the most contemporary in superior graphics and sound chips, step one became as soon as obvious: to procure what the most contemporary high-quality chips may compose. In assembling his originate crew, Charpentier recruited Robert Yannes, a younger engineer who had joined MOS in 1979 and had designed the VIC-20 at home, from a spare prototype board. The crew spent about two weeks researching connected chips industrywide.
“We regarded heavily into the Mattel Intellivision,” recalls Winterble. “We also examined the Texas Devices 99/4A and the Atari 800. We tried to procure a feel for what these companies may compose within the lengthy prance by extrapolating from their latest skills. That made it clear what the graphics capabilities of our machine needed to be.”
The MOS designers freely borrowed solutions that they most popular—sprites from the TI machine, collision-detection ways and persona-mapped graphics from the Intellivision, and a piece plan from their private VIC-20. They then packed as many of those solutions as they may merely into a predefined remark of silicon.
“Al [Charpentier] became as soon as given the liberty, within a undeniable die dimension, to establish aside in every little thing he may, working backward within the dimensions we planned. When he ran out of registers he stopped,” acknowledged Winterble. “We outlined in attain the silicon dimension that would give a yield we be pleased been nice looking to are dwelling with; at that point, a die dimension that became as soon as life like in 5-micrometer skills became as soon as lower than 200 mils. Then we prioritized the necessity list from what wants to be in there to what ought to be in there to what we’d handle to be pleased, so the selections that be pleased been necessary at diverse facets grew to alter into pretty computerized.”
9 months to first-pass silicon
For nine months, Charpentier labored with two draftsmen and one computer-aided-originate operator on the graphics chip whereas Yannes labored with two reasonably hundreds of draftsmen and one CAD operator on the sound chip. They lacked fully the refined originate instruments of this day’s engineering workstations, but they had one readily on hand originate tool realized practically nowhere else within the dwelling-computer industry: a chip-fabrication line on the premises. With this, Winterble explained, a circuit buried deep correct by the chips may be lifted out and prance as a test chip, permitting thorough debugging with out wretchedness for diverse elements of the circuitry. David A. Ziembicki, then a production engineer at Commodore, recalls that traditional fabrication events be pleased been about a weeks and that in an emergency the captive fabrication facility may flip designs round in as little as four days.
The designate of constructing the Commodore 64: No person is conscious of.
The designate of constructing the Commodore 64: No person is conscious of. “I had no formal budget accountability,” acknowledged Winterble, “reasonably hundreds of than Jack [Tramiel] staring at me. Jack acknowledged that budgets be pleased been a license to get hang of.” As a consequence of MOS Expertise’s fabrication facility became as soon as no longer running at plump potential, the equipment frail for C-64 test chips and extra than one passes of silicon would in another case be pleased been slothful. “We be pleased been the utilize of of us who be pleased been there anyway,” acknowledged Ziembicki. “You extinguish a little bit of silicon, but silicon’s pretty cheap. It’s easiest sand.”
Despite the indisputable truth that custom chips are on the total life like costly, the C-64 chips weren’t. Not easiest be pleased been style charges absorbed in firm overhead, but there became as soon as no markup to pay, as there would be pleased been inf the chips had been constructed by one other firm. And yields be pleased been high because the chips be pleased been designed for a used semiconductor-manufacturing course of.
The sound chip became as soon as designed with 7-micrometer skills, cutting down to 6 in areas. (By difference, the custom chip for Atari’s Video Computer Machine, fabricated four years earlier, became as soon as constructed with 6-micrometer skills.) Commodore’s video chip became as soon as designed with 5-micrometer elements.
As a consequence of originate time in decision to silicon became as soon as at a top fee, the chips be pleased been laid out merely in decision to compactly. “We did it in a in point of fact modular fashion,” acknowledged Yannes. As an instance, he well-liked, “the common arrangement of constructing oscillators is to private one after which multiplex it till you be pleased as many as you want. We factual constructed an oscillator module and repeated it, because that became as soon as noteworthy faster than working out all the timing for the multiplexer.”
“What became as soon as unparalleled,” Winterble added, “became as soon as that nine months later, after we came out with the first pass, it functioned excluding for one detrimental sprite.”
In November 1981, the chips be pleased been total. The distinctive intent had been a sport machine, but at this point the deepest-computer market became as soon as initiating to explore promising. At a assembly of Charpentier, Winterble, and Tramiel, the choice became as soon as made to poke for a non-public computer. The next decision to be made, in accordance to Charpentier, became as soon as between a 16-kilobyte and a 64-kilobyte machine, since the custom chips be pleased been designed to handle both option.
“Jack [Tramiel] made the bet that by the purpose we be pleased been ready to originate a product, 64Okay Rams will be cheap enough for us to make utilize of,” Charpentier acknowledged.
When the originate of the Commodore 64 began, the overriding targets be pleased been simplicity and low-cost. The initial production cost of the Commodore 64 became as soon as centered at $130; it grew to alter into out to be $135. The computer would utilize the a similar case because the VIC-20 and the a similar-sized circuit board, to tempo style. “That wasn’t even a choice,” acknowledged Charpentier. “It became as soon as factual common sense. If you occur to’ve obtained a product that’s a winner, why alternate it?” To modify from the VIC-20 to the Commodore 64, the production team had easiest to originate the cartridge slot smaller, alternate the color of the case, and originate a new label.
Furthermore, in decision to designing for efficiency first and worth 2nd, as many engineers have a tendency to compose, the diminutive originate crew at Commodore had cost in mind from the initiating. Yannes, for instance, had made economy his credo when he became as soon as an impecunious high-college pupil buying for elements to private a sound synthesizer. “Anytime I originate one thing, I want to make utilize of the minimum decision of elements doable. It’s a non-public explain. If there’s a spare [logic] gate in a gate package, I’ll work to procure rid of your total package, because in working with a undeniable decision of chips, I wants so that you simply can dissipate every little thing that’s in them. The Commodore 64 became as soon as my strive to private completely the minimal machine that may be constructed out of the video and sound chips assign together.”
Elated Unique three hundred and sixty five days 1982!
In the consumer-electronics industry, new products are traditionally introduced to distributors, sellers, the clicking, and the competition twice a year—in some unspecified time in the future of the first weekend in January and the first weekend in June, on the Chilly climate and Summer User Electronics Reveals (CESs).
“Must you labored for Commodore,” acknowledged Yannes, “you largely needed to be pleased one thing for the Chilly climate CES.” The C-64 didn’t be pleased noteworthy competition on the winter conceal in 1982. Atari became as soon as amassed sowing its 400/800 computer. Mattel introduced the Aquarius computer, and Spectravideo introduced its computer/sport machine, both with little memory and capabilities.
Ziembicki recalled, “All we observed at our gross sales establish aside be pleased been Atari of us with their mouths dropping birth, announcing, ‘How will you compose that for $595?’”
“We be pleased been successful,” Winterble added.
After the conceal, Commodore, which had a reputation for on occasion showing products that never reappeared, needed to procure the 64 into production rapidly. Handiest about a originate changes be pleased been made to ready the machine for production. “What’s within the 64 functionally is what I wished,’ Yannes acknowledged. “What’s within the sound chip is what I wished, and what’s within the video chip is what Al [Charpentier] wanted.”
The truth is, acknowledged Ziembicki, “after it at ultimate obtained into production, we regarded support and asked, why did we wretchedness altering it after January? It wouldn’t be pleased offered one unit less, and we would be pleased saved hundreds of money on style charges.”
About a of the changes be pleased been pretty principal, but they may merely be pleased created as many issues as they solved. The ultimate development became as soon as to resolve “a hiccup” within the video chip, acknowledged Winterble.
When Charpentier first designed the video chip, he explained, his blueprint became as soon as optimum efficiency in both shaded-and-white and color. Old video chips, equivalent to those frail within the Atari and the Apple, had a shaded-and-white frequency of 7.16 MHz—twice the tv color-clock frequency of 3.58 MHz—but this may no longer squeeze enough characters on a line, and it also prompted contaminated talk between the two indicators, causing an object to shift a little to the left or wonderful on the conceal looking out on its color. After the January 1982 CES, when he observed that 40 characters wouldn’t reasonably match onto a TV conceal, Charpentier speeded up the shaded-and-white clock fee and made the two clocks fully asynchronous. Nonetheless since the color and shaded-and-white sets of files be pleased been continuously altering segment relative to each reasonably hundreds of, “the color transitions be pleased been good, but there became as soon as an total swimming enact,” he recalled. The resolution became as soon as to establish aside a segment-locked loop into the machine so the color and the shaded-and-white files would be pleased a continuing relationship. This, Charpentier acknowledged, became as soon as “a Band-Support resolution.”
And that is the reason what it appears to be handle, in accordance to Craig Nelson, director of product style for Epyx Computer Machine of Sunnyvale, Calif. “It’s a in point of fact spruce circuit,” he acknowledged, “excluding for the segment-locked loop, which is factual caught within the center of it.” (Commodore now says it has redesigned the chip to procure rid of the explain.)
As a outcomes of the “Band-Support,” the color files and the shaded-and-white files shift segment by 180 degrees referring to each reasonably hundreds of on successive video fields in decision to altering segment unpredictably. This conforms extra closely to the National Television Programs Committee (NTSC) common, which requires shaded-and-white files to be pleased a clock fee that is an abnormal harmonic of the color-clock fee, so as that the two robotically reverse their relationship each reasonably hundreds of self-discipline—one self-discipline in segment, the next self-discipline out of segment. (In the NTSC common, colours are obvious by the segment difference between the color signal and a color reference signal transmitted on the initiating of each line.)
At the time the common became as soon as developed, commonly on hand circuitry may no longer fully separate the shaded-and-white files from the color: changes in color would lead to changes in brightness and vice versa. It became as soon as to average these changes out over time that the NTSC specified that the relative segment reversal of the two indicators may occur on successive fields. The stop consequence’s extra good-making an are trying color transitions, but the segment shift makes stationary figures appear to jitter. The jitter is terribly obvious on skinny vertical lines, handle those in alphanumeric characters. Nonetheless when the Commodore 64 became as soon as conceived, it became as soon as to be essentially a sport machine, no longer a computer.
Running a 5-micrometer-skills chip at an 8-MHz clock fee precipitated it to dissipate a gargantuan deal of vitality—virtually 1.5 watts. Not easiest did the chip prance snappily, but to forestall the colours from washing out, as they had within the VIC-20, “we went to 12 volt to force the heck out of the color indicators,” recalled Winterble. “We knew we would be pleased a warmth explain.”
At this point Winterble made one other originate fix—welding a diminutive steel tab onto the within of the lid of the shielding enclosure correct by the video chip. When the computer became as soon as assembled, the tab pressed against the dwell of the chip package, forming a warmth-conducting path and turning the shielding into a warmth sink.
Some changes that will want improved the machine did no longer procure made within the traipse to production. As an instance, Yannes acknowledged, the wires for the sound output on the broadcast-circuit board prance alongside the wires for the video signal. As a consequence, the sound output picks up an stressful 15,750 -Hz inform. Rerouting the circuit would be pleased taken time, “and we had a board that labored,” he explained. “At that point, in case you had one thing that labored, you did no longer alternate it.” A circuit-board revision since then has rerouted these lines, Commodore acknowledged.
Nonetheless the designers did if truth be told alternate some issues that labored—in conjunction with one revision that degraded the machine’s efficiency.
Nonetheless the designers did if truth be told alternate some issues that labored—in conjunction with one revision that degraded the machine’s efficiency. The distinctive originate specified a high-quality radio-frequency modulator to transmit the signal to a tv location, but a more affordable modulator became as soon as substituted. “It became as soon as $6.25 to $6.50 for a lawful one, and we ended up spending about $3,” Charpentier acknowledged.
Winterble has a particular be taught about of the $3 modulator: “The 50-cent modulator we be pleased been the utilize of on the VIC-20 wasn’t lawful enough,” he acknowledged, “so we went to a extra costly one.”
Electronic originate wasn’t potentially the most efficient advanced remark because the Commodore 64 went from prototype style into production—the logistics posed a elaborate explain. The C-64 became as soon as designed in Norristown, Pa., at MOS. The VIC-20 assembly line, which became as soon as to begin making C-64s, became as soon as in Santa Clara, Calif. As the C-64 went into production, Commodore became as soon as also opening a new assembly line in West Chester, Pa. There be pleased been extra VIC-20 assembly products and companies in Japan, the establish aside the disk force for the C-64 became as soon as to be manufactured. And the C-64 circuit boards be pleased been being made in Hong Kong.
“It became as soon as hundreds of fun,” acknowledged Ziembicki. “The originate of us would recall an English screw. The production stop would recall metric. Nonetheless they went with what they had. Commodore production became as soon as very lawful at making issues match whether they be pleased been meant to or no longer. Their charter became as soon as ‘Ship ‘em’”
“It takes a in point of fact tricky particular person,” explained Charpentier, “to teach ‘I’m no longer transport these because they’re no longer as lawful as they may merely be’—notably when of us are clamoring to recall them.”
Adjustments continue in some unspecified time in the future of production
The originate of production of the Commodore 64 within the spring of 1982 did no longer signal an stop to the controversy. “The principal is so that you simply can resolve your issues whereas you are running,” acknowledged Ziembicki.
Regarded as one of the most first battles, recalled Charpentier, became as soon as over the structure of the broadcast-circuit board. Commodore’s assembly plant within the United States frail computerized component-insertion equipment, but its Eastern facility did no longer, and the two assembly ways required reasonably hundreds of component spacing. In the stop, the board for the C-64 became as soon as laid out for computerized insertion, and production became as soon as moved to a new plant in Hong Kong that had the computerized instruments.
Issues also plagued a choice of the elements—switches, for instance. “You attain to a choice a switch that’s listed as a consumer switch,” acknowledged Ziembicki. “You originate it in. You call the producer and procure an estimate that sounds life like. Then California [the production division] wants 50,000 a week, but the producer says, ‘We can’t originate that. It’s a consumer switch, but we’re no longer geared for consumer portions.’ At that point, you’re hung up.”
Since Commodore had factual moved its engineering workers from California to Pennsylvania, communication between the originate engineers and the production products and companies became as soon as no longer very lawful, Ziembicki explained. “It obtained to the purpose the establish aside you couldn’t stop working even in case you didn’t procure an answer—you’d factual proceed with the elements that you simply device the production stop may procure.”
And outdoors suppliers weren’t continuously legit. “One offered a vitality provide for engineering approval,” Ziembicki recalled. “It obtained approved, after which the supplier modified the originate and didn’t exclaim anybody.”
Limited changes within the interior originate of the Commodore 64 in some unspecified time in the future of its production prance of additional than 5 million models be pleased slashed manufacturing charges to an estimated one-third of the distinctive $135. Increased quantity is one cost-saving. (Click on on arrow to procure revised circuit board.)
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Charpentier acknowledged that his household with the production team be pleased been pretty agreeable. Winterble’s dealings with them weren’t virtually as cordial, but he realized this acceptable. “I in my view needed to play the heavy on hundreds of stuff,” he acknowledged. “Then Al would poke in and compose some lawful. That arrangement eased hundreds of stress—it became as soon as a mode to procure issues done.”
The most infamous explain became as soon as “sparkle,” a defect that precipitated diminutive spots of gentle to seem on the conceal conceal. The explain became as soon as solved sooner than Charpentier left the firm in September 1982, but studies of the defect persisted smartly into the Christmas season, with press studies citing it for instance of Commodore’s miserable quality regulate. Canny patrons frail it as an excuse to attain perfectly lawful Commodore 64s whereas they be pleased been below 90-day warranty. Since the worth of the machine had dropped $200 within the two months following its introduction, this ruse enabled house owners to develop a repayment of the acquisition designate and pick one other C-64 on the lower figure.
Sparkle became as soon as extensively attributed to bugs within the video chip that became as soon as the center of the machine, but if truth be told it became as soon as precipitated by a ROM chip of which 3 million be pleased been in carrier without a issues in reasonably hundreds of programs, in conjunction with the hit arcade video sport Asteroids. Commodore engineers themselves first hunted for the explain within the video chip. It took them three weeks to pickle the ROM chip because the source of the defect, Charpentier acknowledged. “The explain became as soon as a random event—it didn’t occur always. We device the video chip became as soon as for some cause seeing the unfriendly data. We didn’t even suspect it will perchance well be the ROM. At ultimate we assign the good judgment analyzer on it and tracked it down.” The ROM, which Charpentier and his team had designed years earlier, had a particular pre-charging circuit to originate it prance faster, but the circuit made it sensitive to fraudulent indicators. The video circuitry and the 6510 microprocessor alternated in controlling the machine bus, and when regulate passed compose one to the reasonably hundreds of, voltage spikes be pleased been on occasion generated.
“It factual took location that we hit the valid timing,” Charpentier acknowledged. “If the spike had been about a nanoseconds shorter or longer, it wouldn’t be pleased been a explain. The spike became as soon as factual wide enough that the ROM observed it as a sound handle. It would ignore the next handle request and provides the video chip unfriendly data.” Since the ROM contained the C-64 persona location, the conceal conceal will be plagued by random slices of characters.
Per Nelson of Epyx, “This confetti interference-making an are trying stuff on the conceal, glowingly on occasion known as sparkle, has an awfully un-good property: it causes hardware collisions—the sprites factor in it in actuality exists.” Since the flicker became as soon as precipitated by sinful data fed to the video chip, it caused the circuitry to blame for checking whether the movable conceal objects—sprites—be pleased been protecting background objects on the conceal. So utility that relied on collision sensing to manipulate the whisk of objects on the conceal would poke berserk when confronted by sparkle.
The malicious program within the ROM became as soon as corrected, even supposing Commodore needed to rely on outdoors suppliers for a whereas as it ramped up its new production line. Handiest the first few hundred thousand models shipped had the defect. Nonetheless, Nelson observed, “it doesn’t matter to programmers that it became as soon as mounted. Our utility has to work in each machine accessible.” The most bright resolution for programmers, he explained, is to reproduction the contents of the ROM into RAM, which is legit. Nonetheless this wastes 2 kilobytes of RAM.
“A screw-up in my timing”
To boot to the explain with the ROM, “I made a good judgment error,” Charpentier recalled. The error, which became as soon as corrected on occasion after Charpentier left Commodore, precipitated the early C-64s to generate the unfriendly decision of clock cycles on each horizontal video line. “It became as soon as off by one,” he acknowledged. “As a substitute of 65 clock cycles per line, I had 64.”
As a consequence, the 180-level segment shift between the shaded-and-white and color files, which would be pleased eliminated color-transition issues, didn’t occur. Depending on their color and the color of the background, the perimeters of some objects on the conceal would seem a little out of line. This became as soon as corrected approximately 5 months into production.
Nonetheless main edges are amassed a explain with the C-64. The circuitry that displays both sprite files or background files at any point on the conceal is on occasion slack to answer and overlays the sprite on the background files easiest after it has missed about a pixels.
The C-64 designers weren’t potentially the most efficient ones revising their machine; even some assembly-line workers obtained into the act.
The C-64 designers weren’t potentially the most efficient ones revising their machine; even some assembly-line workers obtained into the act. Since making an are trying out color quality robotically is virtually no longer doable, assembly-line workers be pleased been suggested to flip a potentiometer that controls the color and shaded-and-white indicators till they observed color. As Charpentier recalled, the workers rapidly realized that if they grew to alter into the potentiometer as far as doable, it resulted in saturated color—alternatively it also worn out the shaded-and-white signal. Several thousand computers had been shipped sooner than the assembly-line workers’ “revision” became as soon as observed; by then, some reviewers be pleased been lambasting the C-64 for its “garish” colours.
Quality amassed missing
Despite the indisputable truth that these modifications be pleased been made within the C-64 since its introductions, designers who write industrial utility for the machine would want to procure about a extra. One such alternate will be enough quality regulate. “They don’t test,” acknowledged Nelson of Epyx. “I’ve spread out designate-new Commodores and realized traces lower. They clearly utilize a vitality screwdriver to assemble the C-64, on occasion omit the screw, and chop the traces. How, may you wonder, may that be pleased passed ultimate inspection? Well, those traces are knotted as a lot as the disk-force connectors, which they clearly don’t test.”
In hindsight, Charpentier referred to as life like one of Commodore’s mistakes “no longer coming a little nearer to quality.”
One criticism voiced by designers of add-on hardware for the C-64 is that its minimalist originate outcomes in undesirable interactions between elements of the hardware and utility. As an instance, the circuitry frail to manipulate the joystick and the sport-wander port is borrowed as soon as each 1/60 2nd to scan the keyboard for keys which be pleased been pressed. If the joystick switches are closed, the keyboard-scanning utility will epic that a key has been pressed. Gadgets that connect to the joystick ports can reason unpredictable responses—a explain that would no longer occur if separate hardware had been frail for the two functions.
One other flaw is the computer’s low interior utility. The machine comes up in Traditional when it is grew to alter into on. This will be a leftover from the times of the first Pet computer produced by Commodore, which had no disk-running machine, since there be pleased been no disk drives to be had then. “A lawful disk-running machine wasn’t developed till Pet Traditional 4.0,” Charpentier acknowledged. The C-64 doesn’t utilize this evolved model of Traditional because “it would be pleased required extra ROM than we may assign in.” As a substitute, the machine makes utilize of a miles extra ancient model of Traditional, borrowed from the VIC-20.
“Machine wasn’t tangible—you couldn’t retain it, feel it, or touch it—so it wasn’t worth spending money for.”
The most evident omissions from the Commodore 64’s Traditional are instructions to manipulate the sound and graphics chips. “There became as soon as never any blueprint that the machine would be pleased constructed-in utility to manipulate the graphics or the sound,” acknowledged Yannes. “That became as soon as an obvious portion of the Commodore philosophy; you don’t extinguish money on issues that originate the product extra costly and that most of traders aren’t going to make utilize of.”
“Commodore has continuously paid lip carrier to utility,” Charpentier acknowledged. “They compose enough to procure by after which rely on outdoors sources to maintain the opening. Commodore became as soon as an extension of Jack Tramiel, and to him utility wasn’t tangible—you couldn’t retain it, feel it, or touch it—so it wasn’t worth spending money for.”
The C-64 designers had plans of their private for changes which haven’t yet been utilized. They frail the VIC-20 case to shortcut style, but they did be pleased a new case designed that they meant to substitute in eight to ten months. “It became as soon as thinner in front and had extra of a wedge form to it,” acknowledged Charpentier. “I continuously device the VIC-20 case regarded clunky.” About a new elements be pleased been also to be added to the machine.
The indisputable truth that these changes be pleased no longer been made has no longer in actuality affected the success of the C-64, asserted Brian Dougherty, president of the Berkeley Softworks of Berkeley, Calif. “This machine has potentially the most efficient graphics-conceal functionality of one thing that has yet been done for a TV conceal,” he acknowledged. “It came sloe to being a terrific machine.”
The albatross of the C-64: its disk force
The one principal flaw of the C-64 is no longer the machine itself, but in its disk force. With a reasonably snappily disk force and an enough disk-running machine (DOS), the C-64 may compete within the industry market with the Apple and perchance with reasonably hundreds of industry computers. With the reward disk force, though, it is laborious-pressed to lose its image as a toy.
“Enterprise-oriented utility does no longer explore as lawful as it’ll on the C-64,” acknowledged Dougherty, “no longer because the snide machine isn’t lawful enough but because the disk-force procure admission to is simply too slack; any industry utility requires hundreds of disk procure admission to.” And since the DOS is so prone and lacks elements such because the computerized creating and declaring of directories and keeping song of recordsdata, “it is far extra advanced to carry out industry utility” for the C-64, he added. “Any individual handle Lotus [Development Corp., manufacturer of a popular integrated business-software package] is facing noteworthy extra explain than they did creating utility for the IBM PC, because the PC has an running-machine structure that factual doesn’t exist for this product.
“The in style enter-output machine in ROM is done pretty cleanly, in accordance to running-machine principles. The total routines that want to be there are there, but there’ll be pleased to even be a facility for robotically reading the first song of the disk and booting a extra refined running machine into memory.”
The disk force does if truth be told be pleased a facility for robotically reading the first song of a disk, in accordance to Nelson of Epyx, but since it is no longer documented, it is no longer extensively frail.
How did the Commodore engineers botch up the disk force?
“The disk force? What a gory memoir!”
“The disk force? What a gory memoir!” Charpentier acknowledged. “That needed to compose with the one marketing enter we did win. Marketing acknowledged the C-64 needed to be handle minded with the VIC-20.”
The disk force on the VIC-20, Charpentier explained, became as soon as an instantaneous descendant of the force on the Commodore Pet computer. “We had a parallel IEEE-488 bus for the Pet disk force; and we frail a irregular structure within the early days in repeat to pack data: on the outer tracks, the disk moves faster than on the interior tracks, so the info fee changes in repeat to pack extra data accessible. It became as soon as a good thought, alternatively it became as soon as clumsy, in that you simply’re incompatible with every person else. That is the nut this all began with.”
The VIC-20 disk force became as soon as designed in Japan, and the bus became as soon as modified from parallel to serial to economize. The force is terribly slack because the serial-interface part of the interface controller (the 6522) frail on the VIC-20 does no longer work. As a consequence, the 6502 processor sends out one bit at a time below advise utility regulate, in decision to sending a byte to the peripheral controller and letting it pick care of clocks, data, and hand shaking.
“We mounted the serial-shift register for the 6526 [the interface controller used on the C-64 to replace the 6522] but we couldn’t put it to use, because the disk force needed to be handle minded,” Charpentier persisted. “And, because the processor within the C-64is grew to alter into off for 40 microseconds each 512 microseconds, it kept missing the interrupt indicators that regulate the disk interface. The resolution: slack the force down even extra.”
Velocity became as soon as potentially the most efficient ingredient that may be pleased been modified with out incurring the worth of radical changes within the disk force; if the C-64 designers had been ready to forgo VIC-20 compatibility, they may merely be pleased done noteworthy greater. And within the stop, for plug, the C-64 became as soon as no longer handle minded with the disk force of the IC-20 anyway.
“It all stemmed from the 6522 serial interface no longer working,” Charpentier concluded.
Other producers are seeking to resolve the disk-force explain of the C-64. Some are promoting their private disk drives for utilize with the C-64, but they be pleased realized it advanced to destroy into a market that Commodore controls. Others are promoting packages that may even be loaded into RAM to tempo up disk-switch charges, but this selection applies easiest to make utilize of of the C-64 for programming in Traditional; prepackaged utility loaded into the machine knocks the packages out of RAM. Epyx has launched a ROM-essentially based fully program to tempo disk switch fivefold. Per Nelson, the program will work with any disk-essentially based fully utility. “That’s doable,” acknowledged Charpentier. “The C-64 disk force has its private microprocessor and memory, and likewise which you may be ready to ship files to it to alternate the running machine and to tempo up the serial-bus protocol.”
The common utility for the C-64 disk force can be taught a 256-byte sector each 2.5 revolutions of the disk, or 512 byes per 2nd. Programming tricks frail by Epyx be pleased yielded switch charges of as a lot as 2.5 kilobytes per 2nd. (Among reasonably hundreds of slack disk drives, Atari’s 810 transfers 1000 bytes per 2nd, and the Apple II disk force runs at a maximum of 15,000 bytes per 2nd.)
Artful originate shaves pennies
The Commodore crew had labored laborious to make plug a low initial production cost for the C-64. Vertical integration helped assign elements charges down, and Winterble vetoed solutions for added elements. The designers themselves believed in counting pennies; Charpentier acknowledged he had realized plenty” from Jack Tramiel, who became as soon as “a valid stickler for cost. We agonized over each transistor.”
With a production cost of $135 and a retail designate of $595 at its introduction, the Commodore 64 would be pleased a retail markup comfortably above the industry common of 1 to about a (perchance one to 2 when volumes climb). Nonetheless Commodore has persisted to procure ways to within the discount of both the retail designate, now $149, and the production cost, believed to be between $35 and $50 this day.
Commodore would no longer verify this cost figure. Dougherty of the Berkeley Softworks estimated the prices of C-64 elements, snide don his skills at Mattel and Imagic.
- Three ROMS at $1 each.
- Eight dynamic Rams at $1.85 each.
- SID (sound) chip and VIC (graphics) chip at $4 each.
- RF modulator package, $3
- 6510 microprocessor, $1 to $2
- A handful of TTL, buffers, vitality regulators, and capacitors for a total of $5
- Keyboard, lower than $10
- PC board, $1 to $2
- Plastic case, $1 to $2
- Strength provide and miscellaneous connectors, $5 to $10
- Packaging and handbook, $1 to $2
In extra cost-lowering moves, Commodore has replaced the TTL with less costly custom chips and has realized ways to elongate yields on the sound and graphics chips.
Not all cost-lowering steps be pleased been with out detrimental enact on the machine. The 6567 video chip became as soon as on the initiating packaged in ceramic, even supposing plastic is less costly. “We tried each compose of issues,“ Charpentier acknowledged, “copper-lead frames, steel inserts within the package, and an ungodly decision of reasonably hundreds of issues to procure a plastic package, because a ceramic package is terribly costly. Nonetheless we couldn’t procure a package that ran cool enough. Earlier than I left Commodore, I listed some solutions to within the discount of the vitality, but half of of the chip became as soon as amassed running at an 8-MHzclip. With out a principal redesign, which you may no longer procure the vitality out.”
The originate crew became as soon as independent—they did their private market research, developed their private specifications, and took their child wonderful up by production.
The chip is now encased in plastic. Commodore engineers acknowledged that to boot to redesigning the chip, they be pleased developed a plastic package that may dissipate warmth as smartly as ceramic.
Since the alternate to plastic packaging, a choice of new issues with the C-64 be pleased been reported—issues that are machine-specific or temperature-dependent. One failing that is extensively identified correct by the utility industry is an inclination for the chip to lock up when a program switches graphics modes—from showing a piece plan to showing characters [see sidebar, “A Rich Collection of Graphics Modes”]. “A sport we be pleased been producing began to fail on the production line,” acknowledged Nelson of Epyx. “Then we’d test [defective disks] one more time and they also’d work. It relied on which machine we assign them on and what the temperature became as soon as.” Charpentier speculated that some circuit lines had been left floating within the distinctive originate; miserable processing and high running temperatures would stress chips to the failure point.
One other explain that has begun to emerge in some C-64s is sinful horizontal scrolling of bit-mapped monitors. In a latest overview of the Summer Games, an Epyx sports activities sport for the C-64, the San Jose, Calif., Mercury Files criticized the “flashbulb enact” noticeable in some unspecified time in the future of the swimming event. That, in accordance to Nelson, is no longer an “enact”—the C-64 frail by the Mercury Files reviewer merely doesn’t compose horizontal scrolling smartly.
The liberty ended
Despite the indisputable truth that the machine has its flaws, the designers of the Commodore 64 factor in they came up with many principal advances thanks to the liberty they loved in some unspecified time in the future of the early stages of the project. The originate crew became as soon as independent—they did their private market research, developed their private specifications, and took their child wonderful up by production. Nonetheless as rapidly because the production bugs be pleased been labored out and Commodore knew it had a winner, the company styles, which till then had been on the West Cruise going by the VIC-20 and the Pet computer, moved in.
“At that point, many marketing groups be pleased been coming in to ‘serve’ us,” Winterble recalled. “The next product definition became as soon as going to be device up by one team, and one other team became as soon as to be to blame for getting issues into production, and Al’s team would compose R&D on chips easiest.”
“If you occur to let marketing procure entangled with product definition, you’ll never procure it done rapidly,” Yannes acknowledged. “And you squander the potential to originate one thing queer, because marketing continuously wants a product handle minded with one thing else.”
Charpentier summed up their frustration: “Must you procure many people fascinated a couple of project, all you stop up doing is justifying yourself. I knew the Commodore 64 became as soon as technically as lawful and as low-cost as any product that may be made on the time, but now I needed to listen to to marketing of us announcing, ‘It obtained’t promote since it doesn’t be pleased this, it’ll’t compose that.’
“The liberty that allowed us to compose the C-64 project will potentially never exist one more time in that atmosphere.”
Postscript (as of March 1985)
Of the distinctive Commodore 64 originate crew, easiest Robert Russell stays at Commodore; he is currently a originate manager. The remaining of the crew—Albert Charpentier, Robert Yannes, and Charles Winterble, along with David Ziembicki and Bruce Crocket, who helped debug the project and lift it into production—left Commodore within the spring of 1983 and fashioned the firm Peripheral Visions. Their device became as soon as to originate one other computer. To develop working capital, they took on a contract from Atari—to originate a keyboard for the Video Computer Machine, which became as soon as previewed but then, because the videogame market crashed, never launched. Peripheral Visions became as soon as sued by Commodore, which acknowledged the VCS keyboard became as soon as a project that belonged to Commodore. At this writing, the suit had no longer been resolved.
Peripheral Visions has been renamed Ensoniq and will rapidly liberate its first product, a song synthesizer. Albert Charpentier is currently vp of engineering at Ensoniq, Bob Yannes is senior fashion designer, and David Ziembicki is manager of production regulate. Charles Winterble left Peripheral Visions and is now team vp of electronics at Coleco Industries Inc. of West Hartford, Conn. And Jack Tramiel is currently chief govt officer of Atari Corp., the firm that became as soon as Commodore’s chief competitor within the dwelling-computer market sooner than dropping virtually a thousand million greenbacks in competing against the C-64.
To probe extra
Computer bookstores lift a lawful collection of books on the C-64. Among those suggested are
What’s in actuality correct by the Commodore 64, by Bilton Bathurst, revealed by DataCap of Feneur, Belgium, and The Anatomy of the 1541 disk force, by Lothar Englisch and Norbert Szczepanowski, revealed by Abacus Machine of Immense Rapids, Mich. Computer magazines equivalent to Creative Computing and Compute! overview utility and submit packages that prance on the C-64. The Commodore 64 itself also will be realized at most colossal retailers.
How Programmers Exploited the C-64 Hardware (Slideshow)
The assorted elements of the Commodore 64 hardware also will be frail by myself or in concert to total spectacular outcomes. In the monitors proven right here, the raster-interrupt feature of the Commodore 64 is frail to alternate the colours and the choice, to elongate the choice of on hand sprites, and to alternate between the diverse graphics modes. On this opening conceal of the Summer Games video sport from Epyx, two raster interrupts between the rows of flags are frail to alternate color registers, thus rising the choice of colours on hand on this multicolor persona-mapped conceal. Sprites are also frail to add colours and refined detail.
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