ENVS 1500 Chapter Notes - Chapter 14: Spooling
13 May 2018
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ENVS 1500 Chapter 14 Notes – Summary
Introduction
Security and Data Integrity Protection
• Many additional features built into the command structure reflect the importance of a
flexible file structure to the user.
• The ability to change from one device and one directory or subdirectory to another
without otherwise modifying the file
• The ability to redirect input and output to different devices and files from their usual
locations
Disk and Other I/O Device Commands
• In addition to the file commands, the operating system provides commands for direct
operation on various I/O devices.
• There are commands for formatting and checking disks, for copying entire disks, for
providing output directly to the screen or to a printer, and for other useful I/O
operations.
• Some systems also require the mounting and unmounting of devices.
• This effectively attaches and detaches the directory structure of a device to the already
existent directory structure as a means of adding devices to the system.
• Most operating systems also provide a queuing system for spooling output to a printer.
• The printer is generally much slower than other computer facilities.
• The spooler works by copying the output text into a buffer in memory and then printing
as a separate task.
• This allows programs to proceed as though printing had already taken place.
• Every operating system provides security protection for files.
• Generally, individual provisions are made to protect files from being read, written to, or
executed.
• Some operating systems also provide protection from deletion.
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