After doing some searching WRT USB-SCSI adapters, it got me wondering if such a device could be developed today at much lower cost than in the past.
USB 2.0 SCSI adapters need firmware that can take every USB mass storage command and translate it to a SCSI command, and then translate the results in the reverse direction. This isn’t a perfect solution - it adds delay, may not (probably won’t) support every SCSI command supported by the peripheral, and any translation layer may have bugs.
But modern USB 3 devices typically incorporate UASP - USB-Attached SCSI Protocol. Effectively tunneling SCSI commands over USB. All modern operating systems support it (macOS since 10.8 Mountain lion, Windows since version 8, Linux since kernel 3.15 (June 2014)).
I would think that a chip that can transparently tunnel SCSI commands between a UASP USB port and a SCSI parallel bus would be pretty easy to design. I’ve seen open source hardware projects accomplish far more complicated things, so I’m thinking that the only thing preventing development of an adapter is somebody with the desire and ability to do it.
Does anyone else remember when SyQuest made what was then by far the biggest, fastest and one of the most expensive drives? And a brand that worked beautifully with Macs?
For a few years, SyQuest was the most popular means of transferring large documents for desktop publishing.
But time passed quickly, and in 1996 the company declared bankruptcy. This might have been because “1984 was not like 1984.”
I’d love to see that. Given the surprisingly high price of vintage SCSI adapters of all kinds, I suspect there could be a small market for them, within the range of a Kickstarter project. Unfortunately, I don’t have sufficient technical background in that area.
The problem is, which SCSI? You think there are too many USB versions? SCSI says hold my beer.
For example: my Power Macintosh 8500/180 used one internal-style connector for the 10 MB/sec “Fast SCSI” internal hard drive, and a DB-15 connector for 5 MB/sec “slow” SCSI externally.
But that’s not all! I added an Adaptec PowerDomain 2940U2W Ultra2 Wide SCSI adapter to connect a SCSI Wide (LS) drive. That PCI card had two different internal connectors - 68-pin High-Density Ultra2 Wide SCSI, and 50-pin High-Density Ultra SCSI. And, I think, still another type of 68-pin connector for external High-Density Ultra2 SCSI.
That’s 5 different versions of SCSI in one computer.
All we need to support is the most basic narrow-SCSI port that the original Macs did, including the DB-25 connector at 5M or 10M.
Any higher speed device (fast, wide, ultra, whatever) should be able to auto-detect the slower speed bus and fall back to the lower speeds. So devices can use a cable adapter to work with it. They won’t come close to top speed but they’ll work. Which is the point - to allow access to data stored on otherwise inaccessible drives.
If you want peak performance from your device, then of course, you’re going to need a high performance host adapter. But for most of us who just want to get files off of old storage devices, that won’t be necessary.
Don’t forget single-ended (SE) vs high-voltage differential (DIFF) vs low-voltage differential (LVD)!
I suppose another way to go would be to aim for the highest version of SE/LVD, which should be backwards compatible with all other SE/LVD SCSI versions. At that point, it’s a matter of finding the right physical cable.
(High-voltage differential is a completely separate beast, being electrically incompatible with SE/LVD. Connect an SE/LVD device to a high-voltage DIFF bus, and you will fry the device. As an aside, I keep an old SGI IRIX workstation that has both SE and high-voltage DIFF buses. A nice thing about SGI IRIX is that it reads Apple HFS, as well as a few older Linux and Windows filesystems, so it is pretty versatile. Unfortunately, it doesn’t support HFS+, though you can always use the IRIX dd to copy a drive, regardless of the filesystem.)
The Iomega Zip drive… To me, this might be the most essential third party accessory the Mac has ever had. We were stuck. Floppies were unmanageable. Internet was slow. We needed a way to backup our data. Affordable, fast, and they worked great.
I remember a time when companies would distribute sales literature and promotions on odd-shaped CDs. Some were around 3 inches in diameter, and I think a few were rectangular and between the size of a business card and a playing card. They did get attention, but they never worked well in CD drives, especially those that had slot openings that would not spit them back out. The fad didn’t last long, and I think I threw out all of them years ago.
Affordable: yes.
Fast: compared to other comparable removable media, yes.
Worked great: debatable. Zip drives had one serious flaw: the dreaded “click of death”.
Back in the 1990s I was a software developer working on bespoke software for multi-drive tape & CD duplication. This was before standalone duplicating machines were a thing, so it was a PC with SCSI adapter connected to as many drives as we could fit / stack, with a combination of Turbo Pascal & Turbo Assembler code doing the work. Fun times, and I got pretty good at writing concise, reusable code, but SCSI terminating and drive numbering were a pain in the posterior, and the first CD-R discs were £11 a time, so I had to be very careful when testing things!
We also used Zip disks for a time when the firm I worked for moved into printing. Needless to say, I heard the dreaded Click Of Death many times!
Ironically, while tape, CD and even DVD duplication tailed off over the years, we were still regularly doing floppy disk copying alongside various USB memory sticks when I left in 2012.
Turbo Pascal! Now that brings back memories. That was the first “real” programming language I ever learned after cutting my teeth on Applesoft BASIC in the '80s.
Might the steep declines of tape, CD and DVD duplication reflect the fact that all three formats were used to distribute audio or video entertainment in large runs, but floppy disks and USB memory sticks were more likely to be produced in smaller runs?
I know I’m probably the only one here who’s even heard of it, but I used the ArVid storage solution (quite popular in Russia and CIS back in mid-90s): https://en.wikipedia.org/wiki/ArVid Still have it lying around somewhere, probably.
I’m still using TurboPascal 5 via DOSBox-X on a Mojave system. Works great! Unfortunately the App Store offers no compilers for classic procedural languages.
I haven’t heard of ArVid, but I do remember other devices using VHS tape for non-video storage. Alesis used standard S-VHS tape for their ADAT multitrack audio recording products for many years before later transitioning the platform to other media (like hard drives). It was very popular because it brought digital audio recording down to a price point making the tech accessible for small/home studios.
