Operating System Services for Process Management:
Below is a list of selected operating system services:
Program Execution: The operating system must provide the ability to load a
program into memory and to run it.
I/O Operations: The operating system must provide this capability since users
cannot perform I/O directly.
File System Manipulation: The operating system must provide the capability to
read, write, create and delete files from a user program. There are many details
in file creation, deletion, allocation, and naming that users should not have to
perform. Blocks of disk space, are used by files and must be tracked. Deleting a
file requires removing the name file information and freeing the allocated
blocks. Protections must also be checked to assure proper file access.
Communications: It is the exchange of information between processes that may
be executing on the same computer or on completely different machines. This is
usually implemented via shared memory or message passing.
Error Detection: It is the ability to detect errors in CPU, memory hardware,
I/O devices or in user programs. Error detection occurs at both hardware and software levels. At hardware level, all data transfers must be checked to ensure
that data have not been corrupted or changed. At software level, media must be
checked for data consistency. For example, the number of allocated and
unallocated blocks of storage . should match the total number of blocks on the
device.
Some additional operating system services that do not help the user but ensure
that the machine runs efficiently are as follows:
Resource Allocation: It is the ability to allocate resources to multiple users
or to multiple jobs running at the same time.
Accounting: It is the ability to keep track of and to record which users use
how much and what kinds of computer resources.
Protection: It is the ability to ensure that all access to system resources
is controlled.
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