Night of the Panther

Michael Steeber, writing about a night I vividly remember:

Back in the days when software could be weighed and measured, the release of a new operating system was as big of a deal as any other hardware release. But let’s not forget: updates weren’t free. Mac OS X Panther, released on October 24, 2003 at 8:00 p.m., cost $129.

It was within this context that Apple created “Night of the Panther,” a one-night special event hosted at all 65 U.S. Apple Retail Stores. (The first international Apple Store was still a month away.)

Performa Month: The 520 — A New All-in-One Design

Today, we explore the world of the Performa 520, which was a rebadged version of the LC 520. The two machines were put on sale at the same time, in June 1993. The Performa version was not sold in the United States and came with more bloatware than the LC. (The LC 520 was initially sold only to schools.)

For the sake of this article, I will refer to this pair of machines as the “520,” and unless specifically called out, everything in this column will apply to both machines.

The Design

By the early 1990s, the design of the original Macintosh had gotten pretty tired. Apple had evolved it over time, adding things like internal hard drives, expansion slots, and a slightly larger color screen, but the all-in-one Mac was begging for an upgrade for the mid-90s. Users wanted features like larger screens and CD-ROM drives, and the compact Mac form factor just wasn’t up to the task.

A design project was kicked off to design a new all-in-one for the 90s and was given the nickname “Mondo,” according to Paul Kunkel’s excellent book AppleDesign.

Things did not go well.

According to Kunkel, Apple was going to abandon the all-in-one form factor after the Color Classic shipped, but the idea of making a larger all-in-one wouldn’t die, and in fact, was central to a project with an outside firm named Lunar Design, that was working on concepts for a 10th Anniversary Mac.

While that never happened, the group came up with what would become the 520. Kunkel writes:

To reduce the bulk, lunar allowed the plastic to hug the internal components as tightly as possible — a lower section containing the motherboard and speakers, a middle section containing the floppy/hard drive/CD-ROM, and a top tier containing the monitor — which gave the design a “wedding cake” look and viewed from the back.

On the front, the sensation was reversed, with the largest mass (the screen) at the top and the smallest (the foot) at the bottom. The foot elevated the front of the computer and angled the display back six degrees, continuing the gesture used on the Color Classic and Mac LS, with speakers set behind a radiating perf pattern and rocker buttons controlling column and display contrast.

The design was so strange that Larry Barbera (the Apple manager overseeing the project) could only scratch his head. Since no one at IDg (Apple’s Industrial Design Group) liked the design, Barbera had no choice but to put it on the shelf.

Some months later, John Sculley would ask the team to work on a larger all-in-one, so the design was taken off the shelf, dusted off, and put into production. From what I have read, this led to real tension between Apple’s product and design groups.

Apple’s head of Industrial Design at the time was Bob Brunner, who said, “The conflict between designers and engineers exists because we work side-by-side but think in very different ways. Engineers have to worry about making a product that’s manufactured at a low cost. Designers worry about the look and feel, which can make the engineers’ lives difficult, but the schedule is tight. For this reason, whenever the engineers can take control of design, they do, which makes us miserable.”

This computer is far from the most graceful thing Apple has produced. These photos are of my Performa 580CD, but the form factor is the same as the 520.

Don’t look directly at it for too long, and if you pick one up, be careful, as it weighs 40 pounds.

500 Series

500 Series

Like many Macs of the time, the logic board and hard drive could be accessed with just a couple of screws:

500 Series

While awkward, this design met the goals that Apple had in mind, including the inclusion of a larger display and a CD-ROM drive. The latter required the use of a caddy.

This case would house additional LC/Performa models, including the 550, the 560 Money Edition, the 575, and the 580. It was also used — in black — for the Macintosh TV.

The Specs

While the outside was all new, the inside of the LC/Performa 520 was exactly the same as the LC III, with an additional 1 MB of standard RAM, meaning the 520 shipped with a whopping 5 MB of memory.

The Plan

Once the 520 had graduated from a forgotten design project to be an actual product, it earned a new code name: “Hook.”

Sculley and the company saw this machine as another way to migrate Apple’s user base away from the Apple II and toward the Macintosh. Unlike consumer offerings, the LC 520 would do this in the education market, as Robert Hess wrote for MacWEEK at the time:

Christmas will arrive in July this year for children in the United States when Apple introduces the newest member of its LC line of Macs, the LC 520.

The low-cost LC line, which has been most successful in the primary education market, has only lacked for a CD-ROM-equipped model. That’s the niche Apple intends to fill with the LC 520, which will be available only in the K-12 market, sources said.

Reflecting Apple’s desire to make CD-ROM a standard feature of the Mac line, the LC 520 will ship with a Sony dual-speed CD-ROM player. Built into the Mac’s display are stereo speakers that can enhance both CD-ROM and the Mac’s sound output.

I have memories of using some flavor of the 500 Series in elementary school, playing Odell Down Under and typing in an ancient version of ClarisWorks.

With the LC 520 chipping away at the Apple II’s footprint in schools and the Performa 520 being on sale outside the United States, this new design didn’t make a big impact on the consumer market in the US at first, with Apple’s other Performa models continuing to be sold through big-box retailers.

Performa Month: The First Updates

Last time, we took a look at the very first Performa models that rolled off the line. Those machines shipped in the fall of 1992. By 1993, Apple was ready to revise the lineup:

Performa 250

The Performa 200 had been a rebadged Macintosh Classic II, so for the 250, Apple rebadged the Macintosh Color Classic.

The Color Classic would prove to be the last major update to the compact Mac line, and to mark the beginning of the end, Apple got weird.

Internally, the Color Classic was basically an LC II, complete with a Motorola 68030, with the machine built around a color 10-inch CRT, running at 512 x 384 resolution, slightly different from the 512 x 342 resolution previous compact Macs supported.1

However, the display’s weird resolution had a trick up its sleeve: it could be switched into a secondary mode that let it run at 560 x 384. In conjunction with its LC-style PDS card slot, this meant that the Color Classic supported the Apple IIe card. You can see this card in action in this 8-Bit Guy video:

All of this came to the Performa line with the 250. The Color Classic was sold worldwide, but the 250 was seemingly limited to the UK and Australia. Both featured a 16 MHz 68030 processor (on a slower 16-bit data bus like previous machines), 4 MB of RAM, and either a 40 MB, an 80 MB, or a 160 MB hard drive.

Performa 405/410/430

The mid-range Performa wasn’t as big of an update, with Apple replacing the old 400 with three models: the 405, 410, and 430.

These three machines shared the same core specs as the 400 before them:

  • 16 MHz Motorola 68030 microprocessor
  • 16-bit data bus
  • 4 MB RAM standard
  • 10 MB support (read more about RAM upgrades in these machines here)
  • No FPU
  • LC-style PDS slot
  • Apple SuperDrive 1.4 MB Floppy Disk Drive

So, what do all of those different model names refer to? Slightly different hard drive specs, with prices that don’t make total sense in hindsight:

Model: HDD Size: Price:
405 80 MB $1,300
410 80 MB $1,050
430 120 MB $1,500

If you were annoyed that the black MacBook’s only tech upgrade was the size of its hard drive, be comforted knowing that you weren’t the first to feel that way.

To clarify that chart a little, I should point out that the Performa 410 replaced the Performa 405 in the fall of 1993. It seems that the only difference between the two models was that the 410 came with 512 KB of VRAM, while the 405 came with 256 KB, but that detail isn’t consistent across the sources I have come across detailing these machines.

(The higher VRAM amount meant a machine could support 256 colors, up from the standard 16.)

Performa 450

Performa 450

Image via oldcrap.org

Rounding out the February 1993 updates was the Performa 450. Unlike its siblings, the 450 ran at a faster 25 MHz, up from the 16 MHz Motorola 68030 found in the Performas 400, 405, 410, and 430.

There was more to this $1,800 machine than the faster CPU, as this computer was based on the LC III. Russell Ito covered the LC III in the April 1993 edition of MacUser, writing:

When Apple introduced the LC II, it made only one basic change to the original LC: It swapped a 68030 processor for the original’s 68020. The result was – well, an LC with a 68030 processor. The swap made no difference in performance, and except for the option of running virtual memory, there really wasn’t much to be gained from upgrading to the new machine.

With the LC III, however, the story is a little different. Apple has again made a simple chip swap, but it’ s also made another significant change: In addition to having a faster processor, the LC III is the first low-end machine since the SE/30 to sport a 32-bit wide data bus. The result is significantly better performance.

Weirdly, the LC III and Color Classic came out at the same time, so that article covers both machines that would become the Performas that we’re discussing now. I love the artwork that ran with the article:

Color Classic

This upgrade also brought a higher RAM ceiling of 36 MB, a standard 512K of VRAM, and an updated LC PDS slot. In practice, the LC III/Performa 450 was twice as fast as the LC II and its related Performa siblings.

That performance came with a cost, as the Performa 450 cost $1,800 at launch.


  1. That’s where I got the idea of the name of this very website. 

Performa Month: The First of a New Line of Macintosh: The 200, 400, 600, & 600CD

In September 1992, the first batch of Macintosh Performas were announced. Last time, I wrote about what Apple hoped to achieve with these computers, so it’s now time to discuss the computers themselves.

In the initial press release about the systems, Apple’s Betty Taylor wrote:

All three Performa models use the powerful Motorola 68030 microprocessor, and share the I/O ports and expansion slots that customers expect to find in other Macintosh family members.

In addition, each Performa features Apple’s SuperDrive, a 3.5″ floppy disk drive capable of using disks from Windows, DOS and Apple II computers.

At this point, we need to revisit something that I wrote yesterday… that the Performa line was a bunch of other Macs that Apple tweaked, rebadged, and slapped some third-party software on, all before selling them in big-box stores.

That means talking about individual models can get weird, but that’s what I signed up for when I decided to write this series.

The first three Performa models are perfect examples of this phenomenon:

Pam explains the Performa line

The Performa 200

By 1992, the compact Mac design was eight years old, but Apple was still churning out all-in-one screens with black-and-white nine-inch screens.

Two years before the Performa line launched, Apple put the Macintosh Classic on sale. It was the first Mac sold for less than $1,000 — coming in at $999 — but to make that possible, Apple cut corners. It had no expansion slot, and a lack of a memory management chip meant that the virtual memory feature in System 7 wasn’t supported. The 8 MHz Motorola 68000 made it no faster than machines first sold years before it.

In October 1991, Apple released the Macintosh Classic II. It cost $1,900 — almost double the original Classic — but was a much better computer, complete with a 16 MHz Motorola 68030 CPU and support for up to 10 MB of memory. Sadly, the Classic II still lacked the expansion slot that SE/30 users had come to know and love and had a 16-bit data bus that put a stranglehold on that sweet, sweet 32-bit CPU.

In 1992, someone at Apple took a Classic II off the shelf, taped a “Performa 200” badge on it, and probably went on vacation for six weeks. The two machines shared identical hardware specs, down to the ROM version. As the Classic II was on sale until September 1993, there were several months that both the Classic II and Performa 200 were both on the market, albeit in different sales channels.

Classic II vs Performa 200

These are basically the same computer. Both of my examples are pretty rough, sadly.

Apple said the compact design was “an excellent choice for space-conscious families who value its small footprint that fits into tight quarters and can be easily transported from room to room.”

The Performa 200 retailed for a mere $900, making it the cheapest Mac ever at the time of its launch.

Performa 400

The Performa 400 started life as the Macintosh LC II, with basically identical specs beyond the Performa shipping with 512K of video RAM by default, while the LC II could be had with 256K.

The Macintosh LC was the Mac mini of its day. The original LC was announced in October 1990 and was housed in a 3-inch thin chassis designed to sit underneath a CRT. As LowEndMac reports, its $2,500 price tag came with some compromises:

The first Mac crippled from the ground up, the LC (code-named Elsie, Prism, and Pinball) was designed to a new low price point of $2,500 with 2 MB of RAM and a 40 MB hard drive. The LC was the first Mac to run a 32-bit CPU on a 16-bit data bus, making memory access slower than it should be (the LC benchmarks at about 3/4 the performance of the Mac II, even though both use the same 16 MHz 68020 CPU). Although Apple had retired the 68020 chip with the Mac II in January 1990, it reintroduced it with the LC that October.

To add insult to injury, Apple programmed the ASICs to support no more than 10 MB of RAM even if more was installed.

Despite these issues, the LC was a huge hit, and Apple reportedly sold 500,000 units in the first year.

The LC II came along in March 1992, complete with the whole 16-bit data path/32-bit CPU issue, but now with 4 MB of onboard memory instead of the 2 MB found on the original LC. The most significant upgrade was the price — the LC II sold for just $1,400, or about $3,100 in 2024 dollars.

Performa 400

image via HomeComputerMuseum

When it was rebadged as the Performa 400, all of these features remained, and every model was sold with an 80 MB hard drive as standard equipment. As a bonus, Performa 400 machines came with a built-in modem when the LC II did not.

The Performa 400 sold for $1,180, a discount of $220 from the cost of the LC II. Like the LC II, it included on LC PDS slot for expansion.

Performa 600

The top-of-the-line model was the $2,000 Performa 600. Unlike its cheaper siblings, this machine’s starting point is a bit more complicated.

Performa 600

image via eBay

The 600 was basically a rebadged Macintosh IIvx, which is not a nameplate that brought with it great acclaim, as LowEndMac reports:

The Mac IIvx was an okay computer, but a big “Huh?” for Mac IIci users. Where the LC and LC II had been compromised by using a 32-bit processor on a 16-bit data bus, the IIvx ran a 32 MHz CPU on a 16 MHz bus. This gave it slower performance than the IIci, which was still available (stock IIci tests 30% faster than IIvx; adding 32 KB cache to the IIci bumps this to 60%).

In fact, the old 16 MHz Mac IIx outperformed the IIvx on some benchmarks! Needless to say, most serious Mac users chose the IIci over the IIvx.

The Mac IIvx and its near-twin, the Performa 600, were the first Macs available with a built-in CD-ROM drive and also the first Macs to use a metal case.

(When optioned with that built-in CD-ROM drive, the machine was renamed the “Performa 600CD.” This naming scheme would be used for many, many more computers in the Performa line.)

At this point, things get weird, as we also need to talk about the Macintosh IIvi. The IIvi was based on the IIvx, but lacked an FPU in its default configuration, meaning it was much slower under certain circumstances. The IIvi was not sold in the United States and was on the market for a mere four months.

The Performa 600 used the IIvi’s logic board and therefore also lacked an FPU in its stock form. While IIvi owners may have been willing to plunk down the extra cash for an FPU, I’m not sure Performa shoppers would have been as willing to do so.

History has not been kind to this machine, but it is important to note that it completed the “Good/Better/Best” strategy Apple implemented with these early Performas. All three machines were powered by a 68030, but the Performa 600 was clocked at 32 MHz, twice the speed of the 200 and 400.

It was an interesting option compared to those machines, even if its sibling’s position in the Mac II line was less than great. If you were looking for a Performa and needed maximum modularity, this was the one, as it came with three NuBus slots and one PDS slot.

In true Performa fashion, the 600’s price point of $2,000 was a deal compared to the IIvx’s price of $2,950.

(Tossing in the CD drive cost an additional $500, bringing the 600CD’s price tag to $2,500.)

The key to that price cut was nearly a dozen different CD titles that were bundled with the computer.

In short, the Performa 600 was a weird mashup of two Mac II models stuffed with third-party software.

Performa Displays

As only a single of the original Performas was an all-in-one, most buyers would need to pair their new machine with a display.

Both the 400 and 600 included a DB-15 video port, opening the door to quite a few Apple displays, but the company put the Performa name on two different displays.

The $305 “Apple Performa Display” was equipped with a 14-inch (13-inch viewable) CRT running at 640 x 480 resolution with a dot pitch of 0.39mm. For $95 more, the “Apple Performa Plus Display” came with the same specs, but an improved dot pitch of 0.29, for a clearer picture.

I’ve never seen either of these in person, but this image from Wikipedia raises questions for me about the strength of the built-in foot:

Performa Plus Display

Creating the Template

The Performa 200, 400, 600, and 600CD set the stage for how the entire line would operate. Computers with very similar (or even identical) specs being sold across various sales channels.

To a degree, the system worked, at least at first. Here’s Andrew Gore, writing for MacWEEK in 1993:

The Macintosh Performas put on quite a show last Christmas, exceeding projected sales. Apple said the new consumer Macs sold so well that it will offer new configurations this spring and may add some new models by year-end.

Keith Fox, general manager of Apple USA’s consumer division, said the Performa 400 was the best seller, garnering 60 percent of the line’s sales. The Performa 600 CD, with 25 percent of total Performa sales, did surprisingly well, he said, considering it was the most expensive of the three consumer Macs. In fact, the CD-ROM-equipped 600 sold so fast that Apple couldn’t keep up with demand, he said.

“The CD phenomenon in the Mac industry is amazing. The CD is the gating factor [in Performa 600 CD shipments],” Fox said.

Only the Performa 200 failed to sell as well as projected, representing about 15 percent of total Performa sales, according to Fox.

The sales figures taught Apple that consumers are more interested in modular Macs than in the compact Classic design, Fox said.

He said Apple will expand the Performa line by adding additional peripherals, such as an external CD-ROM drive, and it will increase the software bundled with systems.

Gore continued:

Fox said that 91 percent of Performa systems are being used in the home, Apple’s target market. The majority of home users (33 percent) bought Performas as an educational machine for their children. Nineteen percent bought them so they could do work at home; 18 percent purchased Performas for home-based businesses; and 8 percent bought them for home management.

Of the home buyers, 62 percent had never owned a computer before. Of the 38 percent who had owned a computer before, 30 percent owned IBM PCs and compatibles.

Next time: the first batch of updated Performas arrive.

Welcome to Performa Month

From 1992 to 1997, Apple shipped over 40 Macintosh models wearing a Performa badge. In the years since, the word has become an anathema to many Mac users who were around in that era.1

Throughout August, I will be exploring the world of this computer line in a new series:

Performa Month

And what a confusing world it is!

At its heart, the Performa line is the fruit of badge engineering. This is often found in the car market, perhaps most famously in the Chrysler K-car platform that debuted in 1981. Over 14 years, Chrysler, Dodge, and Plymouth shipped a dizzying array of front-wheel drive cars, all based on the same platform. Features, options, and prices ranged between them, but under the covers, these were all the same car, more or less.

Apple did something similar with the Performa, taking Macs from other lines, tweaking their features, and selling them under the Performa lineup.

In the car world, companies do this sort of work to reach different market segments without needing to create a new product for each type of consumer. In the case of the Performa, Apple wanted to sell computers to reach new users.

The Performa’s Market

Here’s a bit from the company’s press release announcing the new computer line:

Apple Computer, Inc. today introduced a new family of Macintosh computers targeting the consumer marketplace.

Initially available only in the U.S., the new Apple Macintosh Performa series of computers is designed to reach first-time buyers and new users in the home, offering specific solutions for families with school-age children.

It goes on:

“Research suggests more than half of the families in our target market have not yet found a computer solution compelling and flexible enough to meet their needs at home, though many have used a computer either at work or at school,” said Keith Fox, vice president of Consumer Markets for Apple USA.

“With the needs of those customers in mind, we developed the Macintosh Performa. Performa simplifies both the purchase decision and the buying process. We believe the Performa offers the right combination of technology and support to appeal to the estimated 7 million American families which, research tells us, have the buying power but have not yet adopted a PC for their homes.”

To make adopting their first computer easy, Apple shipped Performas as complete systems, complete with their own special edition of System 7.

Performa System Software

The original Performas — which we will discuss next time — shipped with System 7.0.1P. This version of System 7 could run on other Macs, but it came with software created with inexperienced users in mind, including Launcher.

Launcher

This user interface could be managed on behalf of inexperienced or young users, giving them access to only the applications they needed.

Launcher would wind up shipping in all versions of System 7, Mac OS 8, and Mac OS 9. The screenshot above is from the latest of those releases.

This support document outlines the “progressive changes made to system software versions” for the Performa line. With the advent of Mac OS 8 in 1997, Apple did away with the “P” variants of the operating system. However, Performa hardware would still be bundled with third-party software titles to help keep costs down.

Branding

While the model numbers appended to the Performa name are true nonsense in places, the overall branding of the line was meant to be fun, friendly, and approachable. This video came out in the Mac OS 8 era, but I think it provides a good idea of what Apple was trying to portray to potential customers:

To meet these potential customers where they were, Apple put these machines for sale in big-box stores like Circuit City, Sears, and beyond. This is from a press release outlining the strategy:

“Apple will market the new line through major retailers and not its traditional resellers because some consumers are gun-shy when it comes to computer stores,” Bob Puette, president of Apple USA, said.

“First-time buyers don’t buy in computer stores because they don’t feel comfortable,” he said.

The new computers were pilot-tested for 24 weeks in Sears Roebuck & Co., Silo, Office Depot and OfficeMax, said Keith Fox, vice president of consumer markets for Apple USA. He said the distribution had now been extended to Montgomery Ward, Circuit City, Dayton Hudson, Lechmere, Staples, Tops and Tandy’s Incredible Universe.

Sears said it will offer the Performa line at its Brand Central and Office Center departments at 650 retail stores nationwide.

Despite its sales channel, Apple was insistent that the Performa was a full-blooded Macintosh:

“Performa gives you the full power of Macintosh and the ability to perform any home-based assignment, whether it’s a spreadsheet brought home from the office, a child’s homework or entertainment for the whole family,” said Eric Harslem, vice president for desktop computing.

Welcome to Performa Month

Over the next several weeks, I’ll be winding my way through Performa history. If you want to follow along, I have set up a single page to gather all the posts I’ll publish in this series.

Up next: the Performa 200, 400, and 600/600CD. See you tomorrow!


  1. In fact, Jason Snell begged me not to write this series, saying “Those of us who lived it just want to forget. Why won’t you let us forget?”

    On the other hand, Chance Miller encouraged this, saying “those of us who weren’t alive then need to be educated.” 

A Look Back at ResEdit

Howard Oakley:

The Macintosh was intended to be different in many ways. One of them was its file system, which was designed for each file to consist of two forks, one a regular data fork as in normal file systems, the other a structured database of resources, the resource fork.

Resources came to be used to store a lot of standard structured data, such as the specifications for and contents of alerts and dialogs, menus, collections of text strings, keyboard definitions and layouts, icons, windows, fonts, and chunks of code to be used by apps. You could extend the types of resource supported by means of a template, itself stored as a resource, so developers could define new resource types appropriate to their own apps.

Apple’s engineers developed a resource editor that quickly became one of the best-known apps on the Mac: ResEdit, last seen in version 2.1.3 way back in 1994.

I missed the ResEdit era by a few years, but for many people, it was one of the things that made Mac OS so special.

‘For Apple To Win, Apple Has To Do a Really Good Job’

While working on another project, I came across this video of Steve Jobs speaking at Macworld Expo in the fall of 1997. It’s a stunning video for a few reasons.

In it, he announces no products. Instead, he shared some thoughts on how he viewed the mess that Apple had found itself in before it purchased NeXT. In the span of about half an hour, he announced a new Board of Directors and a wide-ranging partnership with Microsoft, complete with Bill Gates making his now infamous appearance via satellite.

The closing of Jobs’ remarks really grabbed me. He insisted that the broader Apple community needed to change how it thought about the company and its relationship with Microsoft and other companies. At the very end, he spoke about how Apple’s brand meant thinking a little differently from the other players in the field. About six weeks later, Apple would launch its Think Different campaign.

What blew my mind — other than how fast the 38 minutes flew by — is that just ten years later, Jobs would be introducing the iPhone.

The Power Mac G5’s Hidden Fan

While working on another project, I came across this delightful blog post by Jay at The House of Moth, about the Power Mac G5:

How many fans does a Power Mac G5 have? Depending on the configuration this answer varies but you can be almost sure the answer is always one short. Let’s take a look at the Late 2005 Quad in this example.

– 2 intake fans (front inlet fan assembly)
– 2 exhaust fans (rear exhaust fan assembly)
– 1 fan in the PCI bay (speaker assembly)
– 1 fan for the hard drives (media bay fan)

6 fans total, right? Wrong. There is a fan behind the hard drive fan as well, part of the media bay fan assembly (in some models), and it does not get the credit it deserves. Without this single fan your G5 can overheat and even die.

So where is this fan located exactly?

I won’t spoil it, but I will say that I had totally forgotten about this quirk of the Power Mac G5, and I gutted a bunch of them back in my day as a Mac Genius.

More on the CD Caddy

Back in 2021, Ernie Smith wrote about the curious world of CD caddies:

The first time I ever saw a CD-ROM, I had never seen a regular CD before, and I thought that it came in a giant plastic case. To be fair to me, I was in middle school, and I had little experience with them. It was in a library, and the screen did not display anything related to multimedia, but general reference information—stuff like databases, for example. A couple of years later, I got a home computer, along with an audio CD player, and soon enough, a CD-ROM. But I always thought about that caddy, which I never saw on any of the computer equipment I owned. Why did it exist? And why, when CD-ROMs trickled down to my home, wasn’t there one?