Week 1 - Major functions of an Operating System
Categorize, describe, and give examples of the major functions of operating systems.
There
are many components that make up the major functions of an operating system
which are also known as Operating System Services. These items typically exist
for assisting the user are as follows:
User interface – is the service that
promotes user interaction which can come in several forms. One is via a
command-line interface (CLI) and is typically text only. Another is a batch
interface where files are executed that hold the commands. A final service is a
graphical user interface (GUI) which is most common and uses a graphical
interaction via I/O which can include menu options and inputs from a keyboard
and/or mouse.
Program execution – is the service that allows a program to run from memory
and should have the ability to end the execution either successfully or
unsuccessfully via error messages.
I/O operations – is the service that allows for I/O devices such as a DVD
or CD drive in order to run a program.
Typically, a user has no control over the I/O devices and the O.S. should have
the ability to run via I/O.
File-system manipulation – is the service that allows a program to read and write as
well as create and delete files and directories. It is the service that allows
the O.S. to have permission to manage access to those files and directories.
Communication – is the service that allows for certain situations when two or more processes need to communicate
and exchange information. This can happen via share memory where those
processes will write to memory. There is also message passing where packets of
information are passed and moved by the O.S. between processes.
Error detection – is the service that allows for various errors to be
detected and corrected. These errors can be in connection to the CPU, hardware,
I/O devices, as well as a simple no paper error with a printer. The O.S. will
do it’s best to correct the error but sometimes will stop the process and
return an error code for more assistance.
The
following remaining services normally benefit an environment with multiple
users and ensure operating system efficiency are as follows:
Resources allocation – is the service that will find
available resources in an environment with multiple users running jobs
simultaneously. This could be with CPU cycles, memory, as well as storage, but
could also include I/O devices as well. It determines how to use these
resources properly when there are multiple calls from different users for the
same resource.
Accounting – is the service that
keeps tabs on what resources are being used and by which users for both usage
stats as well billing, if applicable. This can be useful for anyone needing to
upgrade a computer service or system.
Protection and Security – is the service that
allows for the protection and security of resources in a shared environment.
This allows for multiple users to log on to one system while keeping their
information and data secure from all other users. It can also protect items
such as I/O devices such as network adapters to stop invalid attempts.
Illustrate the hierarchy
of subsystems, components, or subcomponents of operating systems and explain
how they interact with one another.
From my understanding, the subcomponents of a computer are those listed above. Their interaction is dependent on the type of system or environment in which the operating system exists. However, there is much activity within these components and the hierarchy.
To sum up the interaction, it begins with the input from the
user which prompts the operating system to communicate with the computer’s
hardware components. This prompts the activity of the subsystems to then
communicate with each other which are program execution, I/O operations, and
file-system manipulation.
In an environment with multiple users, communication,
resource allocation, as well as protection and security will interact to keep
up with two or more commands. However, these can also take place in a
single-user environment as well.
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