Fail-Softness Criteria in the Realization of a Minicomputer Disk Operating System to be Used in an “Open-Shop” University Environment

Abstract

In disk operating systems of computers without hardware protection, and when the system is used as an “open-shop” installation, the data on the disk must be protected entirely by software measures. Different types of incidents are analyzed which risk to destroy the data in such an environment. A combination of an automatic recovery procedure and of measures to be realized in the operating system is described. It guarantees the integrity of the operating system and of the structure of all files for the large majority of incidents. Any loss of data is limited to the file actually being modified while an incident occurs. If an automatic recovery is not possible, the system can be repaired with a disk scavenger whose main characteristics are outlined.