Caddy Confusion

Trying to answer a complicated question for myself, as a computer user during the multimedia era: Why did the CD-ROM caddy exist, and why didn’t I have one?

By Ernie Smith

Today in Tedium: 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? Today’s Tedium satiates my caddy-related curiosity. — Ernie @ Tedium

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“It’s 50 feet of bookshelves on one little disk.”

— John C. Messerschmitt, the Vice President of North American Phillips, discussing the CD-ROM in one of the first stories written about the concept, a New York Times piece in November of 1984. At the time the article was published, compact discs were still relatively new in the music industry, but had found a place for themselves. The CD-ROM, which had additional error correction capabilities, was pitched as a way to publish large databases without paper, rather than multimedia. (In fact, the article described the storage limitations as this: “It might be true, as Philips boasts in its promotional material, that a CD-ROM disk can store an entire encyclopedia—but only if the encyclopedia has no photographs.”)

CD Caddies

Let’s wrap your plastic and metal in more plastic and metal. (Wikimedia Commons)

Why did early CD-ROMs need to be wrapped in hard plastic, anyway?

Whether the use case was encyclopedias, reference materials, or formative attempts at multimedia, many CD-ROMs released in the early days of the medium came in large plastic containers that had a metal tab on them—or at least were placed inside of them after the fact.

To someone that used the medium later in its history, the existence of the caddy wasn’t just confusing, it was disorienting.

The strange thing about the caddy is that it wasn’t actually necessary for the device to function. As explained in a 1981 New Scientist article, one of the advantages of the CD-ROM over competing optical formats was that they did not need caddies because they were able to handle error correction so well.

The reflective disks are more difficult to press than are AHD disks, but they do not need a protective caddy because the laser beam “sees” straight through surface dirt. Sony has contributed powerful new techniques to correct digital errors which enable a Compact Disc to play without any unwanted sound, even when the surface carries a blemish up to 2.5cm in diameter.

So, as that description makes clear, the caddy predates the CD-ROM by a few years, with the cartridge-like device first appearing with the Capacitance Electronic Disc, a giant vinyl format that used a stylus that was developed before the Laserdisc, but came out around the same time as the laserdisc, a product that did not use a caddy. In the case of the CED (previously mentioned in Tedium in 2016), the reason it needed the caddy was because the disc was susceptible to dust.

CD-ROMs are famous for skipping, especially after being scratched, but dust generally isn’t enough to prevent them from working. So there must be something else at work, right?

And it’s not like the first CD-ROM needed. The CM100, the first CD-ROM drive, used a top-loading mechanism similar to that of many video game console from the 1990s, particularly the Sega Saturn and Dreamcast. An InfoWorld review that was otherwise skeptical of the CD-ROM was nonetheless positive about the device’s error-correction capabilities:

We didn’t find any read errors in the disk data we accessed. In general, we would feel safer storing valuable data on CD-ROM disks than on magnetic media.

The CM 100 also left us impressed by its capability to handle shocks, bumps, and other knacks that would have caused nasty head crashes with many magnetic hard disks. The design of the transport and optical reading system makes anything resembling a head crash almost impossible. The CD-ROM disks are removable and much better protected from physical dam-age than 51/4-inch floppy disks, and they can take fingerprints and even some scratching without data damage. They also don’t wear down from use, since the data are accessed by light beams. Still, CD-ROMs are not impervious to abuse, and they can suffer data loss if they become badly scratched, dirty, or warped.

Other drives of the era, like the Hitachi CDR-1503S (subject of an LGR review) and the Amdek Laserdrive-1 look more like home entertainment equipment than computer drives.

As far as I can tell, the caddy thing came about thanks to Sony, which started selling CD-ROM drives that relied on them starting with the CDU-7101 in 1987.

But it was not the only one. As I was able to decipher using Google Books snippet view techniques on a 1988 edition of the niche publication CD-ROM Review (because I have to do that sometimes to extract relevant information to my beats), there were actually a number of incompatible caddy standards throughout the 1980s. The reason for this was essentially that the standards for the CD—the Red Book and the Yellow Book, among others—did not actually include any standards

Apple CD

Look at this big, honking AppleCD drive. They eventually got smaller, but they stuck with the caddy style for nearly half a decade. (via

Perhaps the most notable user of CD caddies during this era, besides Sony, was Apple, which used caddies for multiple models of its AppleCD. As Apple tended to be big in education markets, it was likely the model that many people saw first, if they did see one.

“The Sony caddy is fast becoming the most common, and is the only one used by more than one manufacturer: Hitachi, Toshiba, and Apple,” writer Alan L. Zeichick explained.

Sony, a longtime player in the standards wars, won this particular standard … not that it really meant all that much in the long run.

And for about half a decade, before CD-ROMs became truly mainstream, it was common to see them in caddy form, rather than tray form.

Caddy Drive

This internal drive offers part of the answer to our riddle as to why the CD-ROM caddy exists. (Derell Licht/Flickr)

Why caddies made more sense in the professional world than the consumer market

Now, I’m not the only person who has been confused by this whole caddy situation. Some of the greatest minds of my generation have been challenged by this unusual quirk of a defining multimedia tool.

For one: Benj Edwards, a pal of mine who writes about stuff like this, speculated nearly a decade ago that the reason why CD-ROMs came in caddies was because the disc media itself was expensive, costing hundreds of dollars and therefore being more valuable than it should possibly be. Which is true. We often think of CD-ROMs in terms of encyclopedias or other reference works, but it was also a useful way to store databases that may have previously only been available in file cabinets. A CD-ROM was obviously easier to transport than a pile of documents, and the convenience initially had a premium put on it so as to not discourage people from buying paper products. (Which sounds insane to write out, I know.)

I have an addition to Benj’s point, and I think it goes back to the setting where I originally saw the CD-ROM in person—a library. In a library, content is intended to be stored for long periods, and where information is not just considered in terms of accessibility but long-term permanence. If a school was likely to have a computer in 1988, where was it likely to be? A library.

As I’ve written in the past about technology often used in libraries, a key goal of information management is to ensure it sticks around a long time. (Disc rot, after all, is a thing.) And, during the early years of the CD-ROM, as I’ve already highlighted, it wasn’t immediately sold as a source for multimedia content, which it eventually became, but a way to get reference content. And reference content, especially in a library or a corporate research facility, means a different type of use than a 15-year-old sticking a Weezer CD in a CD Walkman.

Essentially, the caddy was useful back then because it ensured that the data would be handled in a secure way. And by the time caddies fell out of style, much of this information was moving to online databases or servers anyway. (Or if they did still use CDs, multi-disc readers, which were often distributed in the form of CD-ROM jukeboxes, which were intended for network distribution of content.)

But this doesn’t explain why the caddy eventually saw use in some areas specifically intended for consumers, particularly the Commodore CDTV, a multimedia-focused version of the Amiga released in the early 1990s. (If you get a chance, the retro-tinged British YouTuber RMC is currently doing a series that aims to restore a CDTV. The first episode is above.)

In that case, the 1995 book The Shape of Things to Consume: Delivering Information Technology Into the Home, which analyzed the use of multimedia technology in the home in the context of the Philips CD-i, implies that the long-term archival use cases (and the “professional” image that they portrayed) were the reason for the caddies:

The success of CD-Audio strengthened the view that CD-i should be designed to appear as a machine for home entertainment, like the CD-Audio player and the VCR, but not like the computer. Product mock-ups prepared by Philips’s industrial design centre were variations on the theme of a matte black case the size of a VCR, in keeping with the prevailing (in 1990) dominant design paradigm for audio-visual products including hi-fi. The front of the casing was to be kept as simple as possible with an LED panel and the minimum possible number of buttons. The dominant theme for the consumer is familiarity—a “natural” extension of the consumer electronics products already present in every home. This ‘matte black’ orthodoxy seemed to be as strong for the consumer product as the grey (IBM color) casing was for the professional model. The former was designed to be distanced from the image of a computer; the latter was designed to symbolize it.

The concept of the ‘professional image’ also extends to the means by which the disc is inserted into the player. Philips’s market research suggests that the shiny CD sold in a “jewel case” is a very important part of the appeal of the format to consumers, and helps to justify the price differential between CDs and vinyl discs or tapes. As with CD-Audio, the consumer will put the disc in a tray on the machine. But the professional version uses a “caddy” which transfers the disc to the machine without the disc being touched by the user. This is reckoned to protect the disc, since institutional users will not handle the discs with the same care as domestic users, but it also helps justify charging such users some 30 per cent more than mass market customers for the same product in a different case.

If anything, the authors explain in a footnote, the CDTV’s lack of success simply reinforced the idea that there wasn’t really a use case for caddies in consumer environments.

For consumer use cases, caddies were simply inconvenient, and because they cost money, people didn’t embrace the one-disc, one-caddy ethos the approach required.

“Many consumers would buy fewer caddies than discs, which then involved a fiddly process of swapping discs between caddies,” the authors wrote.

Benj Edwards speculated at one point in his piece that there may have been patent issues at play. Maybe that’s the case—though I couldn’t find anything (I did look). But one other explanation that my Google Books snippet-searching has surfaced that seems to explain the true roots of the caddy: It was a stopgap to an engineering problem.

Screen Shot 2021 03 12 at 11 23 53 AM

I extracted 80 percent of an article using Google Books snippet view to help solve this mystery. Are you proud of me?

During the early history of the CD-ROM, the drives were often external, and as I pointed out before, they were massive, looking more like stereo equipment than disk drives. But here was the challenge of that: How do you fit one of these into a standard 3.5-inch drive bay? You can’t do the flip-up model, really.

Instead, you get a caddy to handle the mechanism part of things.

“Even though caddies aren’t needed for a stand-alone CD-ROM drive, they’re essential for half-height, internally mounted drives,” Zeichick wrote. And of course, this created convenience aspects as well in professional environments: “Caddies can also serve to protect discs from fingerprints and other dirt, and can even act as a pilferage deterrent.”

(As I’ve written, pilferage deterrents were also part of the reason the jewel case initially didn’t take.)

Eventually, the engineering was improved, to the point where the caddy was no longer needed. By that point, the CD-ROM no longer was limited to the library alone, but was heading for its destiny in hundreds of millions of homes.

Regular people have no time for caddies.


The year that the DVD-RAM, an early specification for rewritable DVD drives, was first introduced to the market. Unlike the CD-ROM, the DVD-RAM relied on caddies as a key part of its specification, but gave consumers the choice to use one or the other. It was a niche use case—less niche uses of caddy-style discs included the Minidisc, a Sony-created format that was Big in Japan, and the Universal Media Disc, a Sony-created format used in the PSP. Sony really wanted us to use optical discs in caddies, apparently.

You know, it’s weird. I think back to when I saw that caddy in that library, and thought it to be extremely novel thing, but I didn’t dare take it out to mess with it.

I sort of felt like it was wrong to do so, even though in many ways I found the disc more interesting than the information on the screen.

I sort of wish I had pulled the disc out just to look at it and understand why it did what it did. Instead, 30 years later, you’re getting 2,400 words from me trying to answer this question for myself.

Data Discman

A disc for the Data Discman, an early electronic book which I wrote about a couple of years ago. Again, Sony loves caddies. (Wikimedia Commons)

This was one of my first interactions with a computer, and it was significantly more interesting than the bog-standard PCs also in the library that only ran WordPerfect 5.1 … well, until I figured out that QBasic existed and could play games, too.

Those early experiences in a public library led me into a lifetime of nerdery.

These days, I have a computer that sits next to me at my desk. For some reason completely unknown to me, the disk drive opens on its own, spitting out a tray—the technology that eventually replaced the CD caddy for many use cases.

I’m sure I could fix it, but honestly, it’s kind of heartwarming to see it. It’s sort of like a little reminder of the weirdness and creakiness of early computers, which is what I love to keep around.

This disc drive will never be fixed. May it keep opening forever.


So yeah, that happened. (By the way, a quick shout to all the new readers this week!) Find this one an interesting read? Share it with a pal!

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Ernie Smith

Your time was just wasted by Ernie Smith

Ernie Smith is the editor of Tedium, and an active internet snarker. Between his many internet side projects, he finds time to hang out with his wife Cat, who's funnier than he is.

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