30MB Winchester hard disk drive sold by Watford Electronics, a British computer electronics company. 

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

The term Winchester originated with an early IBM disk drive that featured 30MB of fixed storage and 30MB of removable storage. Its designers nicknamed it Winchester after the .30-30 rifle. Over time, the name Winchester became a general term for hard disk drives, though its use largely faded by the 1990s.

History of the Winchester disk drive

The IBM 3340 Direct Access Storage Facility, code-named Winchester, was introduced in March 1973 for use with the IBM System/370. Developed in San Jose under the leadership of Ken Haughton, it was originally designed around two removable 30MB modules. This 30/30 configuration inspired the Winchester codename, after the .30-30 rifle, though later versions offered higher capacities.

The 3340’s removable disk packs were sealed with their own head and arm assemblies, eliminating the need for a cover to be removed during insertion. Three versions of the IBM 3348 Data Module were sold: one with 35MB, another with 70MB, and a third with 70MB plus an additional 500KB under separate fixed heads for faster access. The drive offered a 25 ms access time, a data transfer rate of 885 kB/s, and included error correction. It remained in production until 1984.

The real significance of the 3340, and the reason the term Winchester technology became synonymous with hard drives, was its innovative head-loading method. Unlike earlier drives, the 3340’s read/write heads did not retract from the disk surface when powered down. Instead, they were designed to land and lift off from the spinning disk, greatly simplifying the actuator mechanism and reducing costs. This design quickly became the industry standard for hard disk drives.