Engineering Design of a Disk Storage Facility with Data Modules

The design of the IBM 3340 Direct Access Storage Facility with IBM 3348 Data Modules incorporates new concepts and required the development of several innovative components, including newly designed magnetic read-write heads. The heads start and stop in contact with the disk and use a tri-rail, air-bearing slider having a low mass. Each data module includes read-write heads, a head carriage, disks, and a disk spindle. The rationale is discussed for the design concepts and for several components, including the data module, head and arm assembly, and the moving-coil linear actuator. A method of improving data integrity, utilizing a “disk-defect skipping” procedure, is described and its performance implications discussed.