Fifteen Classic PC Design Mistakes

There’s no such thing as the perfect computer, and never has been. But in the personal computer’s long and varied history, some computers have been decidedly less perfect than others.  Many early PCs shipped with major design flaws that either sunk platforms outright or considerably slowed down their adoption by the public.  Decades later, we can still learn from these multi-million dollar mistakes.  By no means is the following list exhaustive; one could probably write about the flaws of every PC ever released.  But when considering past design mistakes, these examples spring to my mind.

Special thanks to Steven Stengel of the Obsolete Technology Homepage for providing many of the photos in this article.

Apple III (1980)

The Apple III was Apple’s first computer not devised by Steve Wozniak, Apple’s co-founder.  Instead, a committee of engineers designed it to be the “perfect” business system.  With an absurdly high price (options ranged between $4,340 to $7,800–about $11,231 to $20,185 in 2009 dollars) and numerous bugs at launch, the Apple III was doomed to failure.

Problem #1: No Power Supply Fan

The Apple III’s lack of power supply fan caused system to heat up, warping the motherboard and unseating certain socketed chips.

What Were They Thinking?

According to Apple insiders, Steve Jobs’ zeal for a simple and silent computer design forced the Apple III team to exclude a cooling fan for the power supply.  Apple later suggested a simple fix for the heat-warping problem: raise the Apple III a few inches off a hard surface and drop it, hopefully re-seating the chips in the process. Fortunately, that advice wasn’t required for later Apple computers that lacked fans.

Problem #2: Limited Apple II Compatibility

To run an Apple III in Apple II mode, one had to first boot from a special floppy disk.  Once in Apple II emulator mode, the user could not use any of the Apple III’s enhanced hardware, including 80 column text mode or the real-time clock.  Compatibility with Apple II software was not perfect, as many software packages used direct memory writes in the form of PEEKs and POKEs that didn’t line up with the Apple III’s memory structure.

What Were They Thinking?

Like IBM and the PC/PCjr, Apple wanted a clear product delineation between their “home” machine (the Apple II) and their “professional” machine (the Apple III).  As a result, Apple II compatibility on the Apple III was intentionally crippled.

DEC Rainbow (1982)

In the early 1980s, mainframe giant Digital Equipment Corporation tried its hand in the personal computer market with the DEC Rainbow.  Since industry-wide PC standards had not yet been decided, DEC decided to support the two major operating system platforms at the time: Z-80-based CP/M and 8088-based MS-DOS. The Rainbow contained both these processors and was capable of booting both OSes.  Interestingly, despite the machine’s use of the 8088 and MS-DOS, the computer remained largely incompatible with the IBM PC.

Problem #3: No Way to Format Disks

DEC provided no official method of formatting blank diskettes for use in the Rainbow.  As a result, Rainbow users were forced to buy pre-formatted floppy disks from DEC.

What Were They Thinking?

The Rainbow’s 5 1/4″ floppy disk drive used a proprietary sector format that was incompatible with that of either IBM PCs or CP/M machines.  That alone is not unusual for a machine released in 1982.  But preventing users from using non-DEC floppies seemed like a nickel-and-dime move on DEC’s part to make an extra buck on exclusive disk sales.

Later, third party options for formatting Rainbow disks sprung up, spoiling DEC’s monopoly on floppy sales.

Coleco ADAM (1983)

The Coleco Adam was a classic case of overreaching in the video game and home computer markets.  Coleco had recently found success with its ColecoVision home video game console, and it also wanted a piece of the home computer market as well.  Despite its faults, the Adam had one of the best home computer keyboards of its time, with an excellent layout and feel.  This small plus typically gets buried under the system’s numerous drawbacks.

Problem #4: EM Pulse Erases Tapes

Every time a user switched on or off the system, the Adam’s power supply emitted a strong electromagnetic pulse that could scramble or erase the data stored on magnetic data cassettes that the Adam uses to store its programs.

What Were They Thinking?

In this case, they weren’t.  Insufficient testing and a headlong rush to market likely led to this embarrassing flaw.  Users revolted by the thousands, and nearly 60% of the first batch of Adams were returned as defective.

Problem #5: Printer Required

The Adam could not be operated without the bulky, noisy, slow printer attached — both the system’s power supply and power switch are on the printer itself.  If the printer failed or needed repairs, this took the entire system out of commission.

What Were They Thinking?

Coleco engineers probably figured that reducing the number of cables going in and out of the Adam would make the system more user-friendly, but it turned out to be a half-brained design decision that failed to take the big picture into account.