IBM - Device Support Facilities: User's Guide and Reference - Release 13
From the preface:
"This publication describes the Device Support Facilities (ICKDSF) processor and commands. It also discusses hardv/are considerations, operating system considerations, and planning and installation. It is written for installation managers, system programmers, system operators, and other data processing personnel who manage or use direct access storage devices (DASD)."
This exhibit has a reference ID of CH8332. Please quote this reference ID in any communication with the Centre for Computing History.