History (2004): 0.85-Inch HDD

Two companies announced 0.85-inch HDD, a quarter the size of a 1.8-inch drive, the most tiny rotating magnetic devices never seen with incredible technology even if they were not really successful.

In January 2004, Toshiba revealed two units:

• The MK2001MTN at 2TB was in a volume of 3.3x24x32mm, with 1,000G operating, 3,600rpm rotation speed, 16ms access time, PMR, containing one SDK platter 22mm in diameter and one head with recording density of 80Gb per square inch; it’s aimed at mobile phone market; Imation used it for its Micro Hard Drive available by mid-July 2005
• The MK4001MTD at 4TB with same specs, but into 5x24x32 mm, weighing 8.5 grams, with one disk and two heads shipping in January 2006, being into the Guinness World Records as the smallest hard drive, and currently available on Amazon https://www.amazon.com/Worlds-Smallest-Drive-Toshiba-MK4001MTD/dp/B01LZKG7EG for $18

Toshiba 0.85-inch HDD

Then, in March 2005, Samsung released the 4TB Wallet based on PMR to be produced in 4Q15, rotating at 3,600rpm with SDIO interface.

Based in China GS Magicstor plans also to develop 0.8-inch hard drives to target the Chinese mobile-phone market.

All of them were replaced by flash memories.