The term Winchester comes from an early type of disk drive developed by IBM that had 30MB of fixed storage and 30MB of removable storage; so its inventors called it a Winchester in honor of its 30/30 rifle. Although modern disk drives are faster and hold more data, the basic technology is the same, so Winchester has become synonymous with hard.

The IBM 3340 Direct Access Storage Facility, code-named Winchester, was introduced in March 1973 for use with IBM System/370. Its removable disk packs were sealed and included the head and arm assembly. There was no cover to remove during the insertion process. Access time was 25 millisecond and data transferred at 885 kB/s. Three versions of the removable IBM 3348 Data Module were sold, one with 35 megabyte capacity, another with 70 megabytes, the third also had 70 megabytes, but with 500 kilobytes under separate fixed heads for faster access. The 3340 also used error correction. It was withdrawn in 1984.

The 3340 was developed in San Jose under the leadership of Ken Haughton. Early on the design was focused on two removable 30 megabyte modules. Because of this 30/30 configuration, the code name Winchester was selected after the famous Winchester .30-30 rifle; subsequently the capacities were increased, but the code name stuck.

The significance of this product, and the reason that disk drives in general became known as "Winchester technology" had nothing to do with the configuration of the product. This was IBM's first drive to not unload the heads from the media. The Winchester technology allowed the head to land and take off from the disk media as the disk spun up and down. This resulted in very significant savings and a large reduction of complexity of the head and arm actuating mechanism. This rapidly became a standard design within the disk manufacturing community.

The name stuck in the USSR, Hungary and possibly other countries as an umbrella term for all hard drives; it is still in wide use today.

Named after the .30-caliber Winchester rifle, the 3340 Winchester disk drive is a hard drive developed by IBM that had two 30MB capacity and offered a 30 millisecond (ms) access time. What made this drive significant is the technique where the read/write heads would rise or lift off from the disk while the disk increased and lowered when the disk decelerated. This enabled the heads to not have to move off the disk each time the speed was increased or decreased. Future hard drives after the 3340 began to use this as a standard for hard drive development.

Our unit was marketed by Watford Electronics for use with the BBC Micro and has a serial number of M00612232.