Why are some hard disk enclosures limited in hard drive capacity

enclosuresexternal hard drivehard driveusb

Why are these hard drive enclosures advertised as having 160 GB maximum capacity?

http://amazon.co.uk/dp/B008MRBMPA

USB 2.0 interface (Compatible with USB 1.1), Up to 480 Mbps data
transfer rates, 160GB capacity max

http://amazon.co.uk/dp/B0047YUUN2

brand new 2.5 inch External Hard Disk Drive Enclosure Case,Support
all 2.5 inch (9.5mm) (max. capacity 160 GB) High IDE Notebook Nard
Disk Drive, and It makes high-speed data transfers—-supports USB 2.0
up to 480Mbit/sec, USB 1.1 up to 12Mbit/sec;

http://amazon.co.uk/dp/B00AVXMFIG

Maximum hard disk capacity: 160 GB

Best Answer

The way most vendors work, they do not re-qualify out-of-production hardware for the latest specifications (unless some huge purchase contract relies on it, anyway), so as long as these old models stay in stock, their specs say the same. They may or may not support more modern, higher density hard drives, but vendors and the manufacturer won't guarantee it.

But why 160GB? It's not a common PC BIOS or CHS->LBA limitation, the closest would be 128GB. Back in 2007, 9.5mm drives went to 160GB while 200GB+ you had to buy a 12.5mm drive. That was just the state of the industry at that moment. You can see discussion in Mac forums like this: http://ask.metafilter.com/63097/Whats-the-max-size-harddrive-I-can-put-in-a-MacBook