Watch a 34-year-old 20MB Apple Hard Disk 20SC work with a modern iPhone

Apple Hard Disk connected to iPhone
Apple Hard Disk connected to iPhone (Image credit: iMore)

What you need to know

  • The 20MB Apple Hard Disk 20SC was released in 1986.
  • It used SCSI to connect to computers.
  • And it works with iPhone and iOS 13.

Plugging accessories from more than 30 years ago into a device that wasn't even conceived back then is never going to get old. So when I saw that someone had taken a 20MB Apple Hard Disk 20SC and plugged it into their iPhone – and got it working! – it caught my attention.

Particularly entertaining is the ridiculous number of adapters and dongles needed to make this work. But seeing this hard disk from 1986 connected to a phone with music streaming off of it is way more interesting than it probably should be.

I admittedly know almost nothing about this particular accessory. But that's where Wikipedia comes to the rescue:

The 20SC originally contained a half height 5.25" Seagate ST-225N 20MB SCSI hard drive, but was later manufactured with a full-height 3.5" MiniScribe 8425SA 20MB SCSI hard drive. The latter drive was the same size as the drive inside the Macintosh Hard Disk 20, but 10 to 15 MB over what had previously been offered by Apple for the II family. The same drive mechanism would also be offered 6 months later as a built-in drive option on the Macintosh II and SE. It had two standard Centronics 50-pin connectors, one for the System and one for daisy-chaining additional SCSI devices and a SCSI ID selection switch. An external terminator was required if it was the only SCSI device connected. The case itself could accommodate a 3.5" or 5.25" full-height hard drive mechanism. Indeed, the case design would be reused unchanged (in Platinum only) for 3 more models introduced the following year: 40SC, 80SC & 160SC (offering respective Megabytes of storage). While the transfer rates were significantly higher due to the faster SCSI bus technology, the actual transfer rate varied from computer to computer thanks to different SCSI implementation based on developing industry standards.

So, now you know!

Hopefully you find plugging old things into new things as mesmerizing as I do. And if not, it's Lory's fault for signing me up.

Sorry, Lory!

Oliver Haslam

Oliver Haslam has written about Apple and the wider technology business for more than a decade with bylines on How-To Geek, PC Mag, iDownloadBlog, and many more. He has also been published in print for Macworld, including cover stories. At iMore, Oliver is involved in daily news coverage and, not being short of opinions, has been known to 'explain' those thoughts in more detail, too. Having grown up using PCs and spending far too much money on graphics card and flashy RAM, Oliver switched to the Mac with a G5 iMac and hasn't looked back. Since then he's seen the growth of the smartphone world, backed by iPhone, and new product categories come and go. Current expertise includes iOS, macOS, streaming services, and pretty much anything that has a battery or plugs into a wall. Oliver also covers mobile gaming for iMore, with Apple Arcade a particular focus. He's been gaming since the Atari 2600 days and still struggles to comprehend the fact he can play console quality titles on his pocket computer.