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CD-ROM “Backpack”
I recall when our school library proudly obtained one of the first 12″ LaserDisc and (soon after) an early CD-ROM drive. I also recall that, in those early days, a CD-ROM drive would cost over $3000 (more than the whole rest of the computer system). By 1990, CD-ROM drives (and the CD disc media) were rapidly coming down in price, but they still weren’t a common house-hold item.
MicroSolutions came up with a brilliant product that made use of the LPT port to add CD-ROM capability to these old systems. If nothing else, this let you use your PC to listen to CD-audio music. But there were situations of using CD’s to pass around large amounts of data (just not so much for typical home users). Myst and Sierra’s Phantasmagoria were two of the earliest CD-ROM games for mainstream home-computer gaming, such that 1993 marked a turning point in the expectation of commercial games (such as spoken voice-overs to dialog or studio-quality cut scenes, at least that’s what corporate game companies started assuming).
Multi-media was about to become the rage of the mid-1990s. This being a “pre-1993” system, a CD-ROM isn’t really necessary as it generally wouldn’t yet be found in a home-PC system. On review, it seems the earliest MicroSolutions CD Backpacks were available in 1994, so it is not exactly “period correct” but would be a reasonable upgrade/add-on to this kind of system. Using a CD is yet another way to quickly transfer in bulk amounts of files into the system (by burning the file content from another modern PC), but will be limited to ~650MB at a time.
The CD-ROM Backpack is a well-known item in the retro community (see here for info and drivers). But one interesting thing I wanted to remind about is that you can use the backpack to tether in other LPT devices at the same time. As shown below, I have the SDLPT connected, and its driver recognizes the device just fine (I get a drive letter for both the SDLPT and the Backpack). The rear port is marked as “printer” but any device using DB25 is suitable. Or, of course, you can have a printer (or the Retro-Printer) attached there as well.
NOTE: Finding one of these for the original IBM 5150 has proven difficult (or driver software that allows newer MicroSolutions backpacks to work on the 5150). Such a thing did exist, just it is a bit elusive to find a compatible setup. But that much media is generally overwhelming for a humble 4.77 MHz 8088. The issue is that the 8-bit x86 version of the drivers only works with one or two early specific model numbers of these Backpack devices. The newer drivers use newer CPU instructions (some 286 or 386 specific stuff), making it “16-bit software” that won’t run on the original 8088 CPU. It was a similar issue for 3COM NIC drivers, until someone patched the .COM file itself.
For archive of more info, I discussed the CD Backpack a bit here:
MicroSolutions 190130 CD-ROM BACKPACK notes in 2024 (vs SDLPT) | Vintage Computer Federation Forums
Introducing the Parallel Cable (from 1952): It always confused me to call these “printer cables.” The DB25 standard was originally a serial-cable, that had a ton of secondary pins (probably since military-specs are big on redundancy in case one system fails). The 1978 IBM 5110 has a group of DB25 connectors used to connect a disk drive to that system (as well as a printer). But by mid-1980s it was fairly common to always refer to these just as “printer cables.” When getting one of these cables, pay attention to the gender of the ends (male has pins, while female has sockets to receive those pins). You can find “gender-changers” for either end, as nearly every combination of cables exists. If the ends are the same, it is generally an extension-cable so you can place an attached device further away from the system.
