Teardown of a 38.5kg IBM Hard Disk from the 1980's

I came across this video today which shows a tear-down of a suitcase-size heavy hard disk from the 1980’s that was used in a bank, which cost about $250,000 at the time. :eek:

Going by the video, the hard disk is an IBM 3390 model 2 and going by the linked IBM specification page, it appears to have a capacity of 3.78GB. it weighs 38.5kg, has 9 platters and requires an external controller as there’s no electronics in the hard disk apart from a small IC for each head.

The actual storage device for it would have contained 2, 4 or 6 of these hard disks and the controller, so the maximum storage capacity with 6 would give a total capacity of 22.7GB. The actual storage device would be similar size to a tall domestic fridge/freezer. Throughput was 4.2MB/s, 12.5ms average seek and 7.1ms latency. Going by the latency, its spindle appears to be about 4200RPM.

The video is quite long (43 minute) but well worth looking at the first few minutes. :cool:


Massive disks. :eek: I wouldn’t mind lugging that around to have a 20GB media player in my pocket. :bigsmile:

If I recall right, I bought a 20GB 3.5" HDD at the end of 2001, showing just how much technology has improved in just 12 years. Being a student, I couldn’t afford the 40GB HDD the shop had. :wink:

11 years on and 64GB microSD cards are widely available, which back in 1989 would have required 3 of those tall-fridge size storage devices. :eek:


These were the first HDDs I ran commercially. State of the art, at the time; but astonishingly just 61.5 Megabytes per drive.


I am showing my age :slight_smile:

Today, I have more than 10Tb on my home network :bigsmile:

Regds, JR

I am surprised at the claimed capacity of these massive drives - I thought they were still in Mb capacities back then, not Gb.

Hi Christine,


Your maths is as bad as mine then :slight_smile:

The maximum capacity (with 4 strings of 4 drives) was 1.032 billion bytes, which I think is just less than 1Gb (if my maths is right).

Regds, Jeremy

I wonder how long it will be before we’re laughing at our current SSDs :wink:

[QUOTE=DoMiN8ToR;2667649]I wonder how long it will be before we’re laughing at our current SSDs ;)[/QUOTE] Two minutes after they open their own stand-up show? :stuck_out_tongue: