XT

Ancient Technology

My father handed me a crate the other day as part of a cleanup, to see if I wanted anything he’d found.

I didn’t think the bits would be as old as they were, and thought it’d be great to share what they were. I’ve used a PS4 controller for reference as I couldn’t find a banana.

First up is a very long ISA card, from an XT PC. This was purely an IDE controller – giving you the ability to add on a floppy drive or hard drive to your PC. The board itself actually says the year of manufacture – 1985.


1985 XT PC ISA Controller Card

There’s two cables, each allowing 2 devices. This goes back to the primary and secondary days of drives, where you needed to set the jumpers correctly on the back for them to be detected properly. I measured it, and it’s 35cm long!

Next up is a 3 button serial mouse. On the back is a switch to toggle between 2 and 3 buttons, which was to work around incompatibilities between the two configurations, as mentioned on the Wikiepedia article. Of course this is an old ball mouse… and someone opened up a Microsoft Serial Mouse if you want to see the ball and wheel components.

3 button Serial PC Mouse

This one’s a bit harder to date – it’s probably XT PC era too with the 3 button switch, and long before the PS/2 mouse came out in the late 1980’s.

Here we have some hard drives. They’re 3.5″ but much chunkier than the ones of today, about double the thickness. I believe they’re both 20MB – yes megabyes! At the time of this, 360KB 5 1/4 floppy disks were the norm – About the equivalent of 55 floppies could be stored on a 20MB HDD.

20MB IDE HDDs, XT PC era (198X)

The data connector on this fits the cables on the ISA card from earlier. I remember in my childhood having a 40MB HDD bought for $600AU in the early 1990s. Back in 1990 accordign to this US copy of InfoWorld, these 20MB HDDs would have cost US$699 as an addon when buying a PC.

Last up was something I was much less familiar with – a 5 1/4 inch HDD. I found a page selling the same model if you want to buy one for yourself. I couldn’t tell from looking at the unit, but based on all the links it seems to have a capacity of 42MB.

Mitsubishi 5 1/4″ HDD back (Centre)

Mitsubishi 5 1/4″ HDD front (Centre)

There is a date on this one, 1989. Because many computers had slots for 5 1/4 inch floppy drives, it made sense to have hard drives at the same size. They fell out of fashion , and the 3 1/2 inch size became the new standard, matching the 3 1/2 inch floppy disks and drives of the time. Again this one has the same connectors as the other hard drives I have. Also, those molex power connectors survived a very long time in the PC world!

Also on the back of this drive, notice the amount of switches you need to set correctly – 14 in total. I’d be surprised if anyone misses troubleshooting an incorrectly set HDD with that many combinations of options, and slow startup times.

That’s the lot – always fun to go back over the old technology and see what was normal.