Why Did Early CD-ROM Drives Rely On Awkward Plastic Caddies?
These days, very few of us use optical media on the regular. If we do, it’s generally with a slot-loading console or car stereo, or an old-school tray-loader in a desktop or laptop. This has been the dominant way of using consumer optical media for some time.
Step back to the early CD-ROM era, though, and things were a little kookier. Back in the late 1980s and early 1990s, drives hit the market that required the use of a bulky plastic caddy to load discs. The question is—why did we apparently need caddies then, and why don’t we use them any longer?
Caddyshack
The Compact Disc, as developed by Phillips and Sony, was first released in 1982. It quickly became a popular format for music, offering far higher fidelity than existing analog formats like vinyl and cassettes. The CD-ROM followed in 1985, offering hundreds of megabytes of storage in an era when most hard drives barely broke 30 MB. The discs used lasers to read patterns of pits and lands from a reflective aluminum surface, encased in tough polycarbonate plastic. Crucially, the discs featured robust error correction techniques so that small scratches, dust, or blemishes wouldn’t stop a disc from working.
Notably, the first audio CD player—the Sony CDP-101—was a simple tray-loading machine. Phillips’ first effort, the CD100, was a top-loader. Neither used a caddy. Nor did the first CD-ROM drives—the Phillips CM100 was not dissimilar from the CD100, and tray loaders were readily available too, like the Amdek Laserdrive-1.
So where did caddies come from? The concept had existed prior to CDs, most notably for the failed Capacitance Electronic Disc format created by RCA. Those discs were highly susceptible to problems with dust, so they were kept in caddies for their protection. For CDs, the caddy wasn’t a necessity—the plastic optical discs were robust enough to be handled directly. And yet, in the late 1980s, caddy CD-ROM drives started to become the norm in the nascent market, with Apple and Sony perhaps the most notable early adopters.
The basic concept of the caddy is fairly obvious by its design. Various non-compatible versions existed from different manufacturers, but the intent was the same. The CD itself was placed in a plastic case with some kind of sliding shutter. This case protected the CD from scratches, dust, smudges, and other contaminants. When it was placed in a drive, the shutter would slide or rotate out of the way, allowing access for the optical head to read the disc.
For many early applications, CD-ROMs were very much an archival format. They offered long-term storage, were non-writable, and had huge capacity. They were perfect for creating digital encyclopedias, with a single disc able to replace a stack of bound volumes that would take up a whole shelf. They were also perfect for commercial or industry use, where large databases or reference volumes could be stored in a far smaller format than ever before.
In these cases, though, it’s important to remember that CDs were quite expensive. For example, in 1986, a copy of Grolier’s Academic Encyclopedia would cost $199—or roughly $570 in today’s money. As robust as CDs were, it was at times desirable to protect such an investment with the added safety and security of a caddy. This was particularly useful in library, school, and business contexts, too, where end users couldn’t always be relied upon to use the discs gently.
Caddies also offered another side benefit of particular use to the radio industry. They made it very quick and easy to change discs, easing the work of on-air DJs as they cued up songs. Compare the ease of slamming in a cartridge, versus extracting a disc from a jewel case and gently placing it in a tray-loading drive. Under the pressure of a live broadcast, it’s clear to see the benefit of the caddy design. Particularly as sloppy handling would quickly damage discs that were on heavy rotation.
Caddies made sense at a time when the CDs and their content were incredibly expensive. They also made sense for professional media and corporate users. However, for the consumer, they quickly became a frustration rather than a boon.
The problem for home users was simple. Caddies added a certain level of expense that became less justified as the price of CD-ROM titles came down. The intent was that users would have a caddy for each disc in their collection, protecting the CDs and making them easy to load. However, many home users only had one or a handful of caddies. This meant users were often swapping discs from caddy to caddy, with the repetitive manual handling negating any benefit of the caddies in the first place. It quickly became an unwelcome chore for owners of caddy-loading drives.
As is the way, the market soon responded. By the late 1990s, caddy-based CD drives had mostly disappeared from the consumer market in favor of more convenient, caddy-free drives. Customers wanted easy-to-use drives, and they had no desire to put up with fussy plastic cases that were ultimately unnecessary. Tray-loaders became the norm for most CD-ROM applications, with slot loaders becoming more popular as a fancier option in some premium hardware.
Caddies did persist, but in more niche contexts. Standards like Mini Disc and UMD relied on integral, non-removable caddies, because Sony could never quite let go of the idea. Similarly, some early DVD-RAM drives relied on caddies too, as have various high-capacity optical archive standards. In these applications, caddies were chosen for two reasons—they were there to protect media that was either particularly delicate, valuable, or both. In the vast majority of cases, the caddy became an integral part of the media—rather than an external cart which discs could be swapped into and out of.
Caddy-based CD drives represent a transitional period in the early days of optical media. The lines between serious archival users and home users were blurred, and nobody quite knew where the technology was going. They highlight a period when engineers and manufacturers were still exploring the best methods build reliable drives that best met their users needs. From a consumer perspective, these protective devices are now curious relics in the post-optical era—a reminder of when laser-based media was on the absolute cutting edge of technology. How times have changed.