ENVS 1500 Lecture Notes - Lecture 31: Management System
13 May 2018
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ENVS 1500 Lecture 31 Notes – Input/output Services
Introduction
• Most modern systems also provide encryption protection and journaling, a technique
which assures the currency and integrity of files when system failures occur during file
changes.
• Some file management systems also provide advanced features, including auditing,
backup, emergency retrieval and recovery mechanisms, file compression, and
transparent network file access.
• File management systems are particularly important in systems in which secondary
storage devices are shared in common by multiple users
• Since they provide a directory system that assures that there is no duplicate use of
physical storage
• Without this facility, it is likely that users would unintentionally overwrite each other’s
files.
• And, of course, we already noted that the file management system also provides file
access protection between the different users.
• The file management system is discussed more fully.
• We introduced the concept of interrupts and showed the various techniques for
handling I/O.
• Programs that implement these concepts are known as I/O device drivers.
• It would be awkward to require each program to provide its own I/O services.
• I/O device drivers are important because they are available to serve every program that
will be executed on the system and provide a standard methodology for the use of each
device.
• Even more important, the use of standard I/O drivers within the operating system limits
access and centralizes control of the operations for each device.
• The currency and integrity of files when system failures occur during file changes.
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