Operating System Functions
What is an Operating System
The operating system is the core software component of your computer.
It performs many functions and is, in very basic terms, an interface
between your computer and the outside world. In the section about
hardware, a computer is described as consisting of several component
parts including your monitor, keyboard, mouse, and other parts. The
operating system provides an interface to these parts using what is
referred to as "drivers". This is why sometimes when you install a new
printer or other piece of hardware, your system will ask you to install
more software called a driver.
What does a driver do?
A driver is a specially written program which understands the operation
of the device it interfaces to, such as a printer, video card, sound
card or CD ROM drive. It translates commands from the operating system
or user into commands understood by the the component computer part it
interfaces with. It also translates responses from the component
computer part back to responses that can be understood by the operating
system, application program, or user. The below diagram gives a
graphical depiction of the interfaces between the operating system and
the computer component.
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Other Operating System Functions
The operating system provides for several other functions including:
- System tools (programs) used to monitor computer performance, debug problems, or maintain parts of the system.
- A set of libraries or functions which programs may use to
perform specific tasks especially relating to interfacing with computer
system components.
The operating system makes these interfacing functions along with its
other functions operate smoothly and these functions are mostly
transparent to the user.
Operating System Concerns
As mentioned previously, an operating system is a computer program.
Operating systems are written by human programmers who make mistakes.
Therefore there can be errors in the code even though there may be some
testing before the product is released. Some companies have better
software quality control and testing than others so you may notice
varying levels of quality from operating system to operating system.
Errors in operating systems cause three main types of problems:
- System crashes and instabilities - These can happen due to a
software bug typically in the operating system, although computer
programs being run on the operating system can make the system more
unstable or may even crash the system by themselves. This varies
depending on the type of operating system. A system crash is the act of
a system freezing and becoming unresponsive which would cause the user
to need to reboot.
- Security flaws - Some software errors leave a door open for the
system to be broken into by unauthorized intruders. As these flaws are
discovered, unauthorized intruders may try to use these to gain illegal
access to your system. Patching these flaws often will help keep your
computer system secure. How this is done will be explained later.
- Sometimes errors in the operating system will cause the
computer not to work correctly with some peripheral devices such as
printers.
Operating System Types
There are many types of operating systems. The most common is the
Microsoft suite of operating systems. They include from most recent to
the oldest:
- Windows XP Professional Edition - A version used by many businesses
on workstations. It has the ability to become a member of a corporate
domain.
- Windows XP Home Edition - A lower cost version of Windows XP which is for home use only and should not be used at a business.
- Windows 2000 - A better version of the Windows NT operating
system which works well both at home and as a workstation at a business.
It includes technologies which allow hardware to be automatically
detected and other enhancements over Windows NT.
- Windows ME - A upgraded version from windows 98 but it has been
historically plagued with programming errors which may be frustrating
for home users.
- Windows 98 - This was produced in two main versions. The first
Windows 98 version was plagued with programming errors but the Windows
98 Second Edition which came out later was much better with many errors
resolved.
- Windows NT - A version of Windows made specifically for
businesses offering better control over workstation capabilities to help
network administrators.
- Windows 95 - The first version of Windows after the older
Windows 3.x versions offering a better interface and better library
functions for programs.
There are other worthwhile types of operating systems not made by
Microsoft. The greatest problem with these operating systems lies in
the fact that not as many application programs are written for them.
However if you can get the type of application programs you are looking
for, one of the systems listed below may be a good choice.
- Unix - A system that has been around for many years and it is very
stable. It is primary used to be a server rather than a workstation and
should not be used by anyone who does not understand the system. It
can be difficult to learn. Unix must normally run an a computer made by
the same company that produces the software.
- Linux - Linux is similar to Unix in operation but it is free.
It also should not be used by anyone who does not understand the system
and can be difficult to learn.
- Apple MacIntosh - Most recent versions are based on Unix but it
has a good graphical interface so it is both stable (does not crash
often or have as many software problems as other systems may have) and
easy to learn. One drawback to this system is that it can only be run
on Apple produced
hardware.
Applications
What is an application
Applications are programs that are installed. on computers to give users
the ability to do specific tasks. For example, Microsoft Word® is a
program that gives the user the ability to write documents. Some
program packages come in a set with multiple programs included to
provide multiple capabilities such as the Microsoft Office® suite of
programs. This suite of programs also includes Microsoft Outlook® which
is used to send and receive e-mail. It also includes other programs
with more capabilities.
How Application Programs Work
Application programs are written in a text based computer language as
mentioned in the section about hardware and software. Once written,
they are compiled into a binary language the computer understands. The
application programs use function calls (as described in the section
about operating systems) to interface to the various computer
peripherals such as your keyboard, mouse, screen, printers, and other
devices. Most of these function calls are provided by the operating
system so the application programs are usually compiled for a specific
operating system such as Microsoft Windows 2000®, Microsoft Windows XP®,
or Microsoft Windows 98®.
Application Problems
An application program is a computer program. It is written by human
programmers who make mistakes. Therefore there can be errors in the
code even though there may be some testing before the product is
released. Application programs vary widely in the quality of the code.
Errors in code are referred to as "bugs". Bugs can cause unpredictable
results including system crashes, inability to perform expected
functions, or providing an exploit for an attacker who wants to gain
control of your system.
Application Acquisition and Installation
You get applications several ways. The most common way is to purchase
it in a store and you will brind a CD home and install it on your
computer system. The ways you may get applications include:
- Purchase of a program from a store.
- Download a purchased program on the internet.
- Download a shareware program on the internet.
- Download a free program on the internet.
Whether purchasing a program or downloading one for free on tHe
internet, you should be aware of the quality of the product you are
placing on your computer system. Ask yourself the following:
- Do I know who made this product and are they a trustworthy source?
- If the product is free, do I know why it is free?
- Is there some hidden purpose for the product?
- What is the reputation of the maker of the product?
- What problems do users of the product have?
Before downloading a product or purchasing a product you should always
spend at least a few minutes researching it. You should at least do a
quick search on
the Gigablast search engine
using the product name and the name of the product producer. You
should perform a Gigablast internet search and possibly Google groups
search to find out where discussions about the product have taken place.
There are also many product evaluation sites that can be used to
obtain reviewers and users ratings of the product before you buy or
install it. Downloading and install the wrong products can not only
seriously impede the performance of your computer system, it can also
cause your privacy to be invaded.
Bad Applications
There are many types of applications that can cause problems on your computer system.
- Applications with serious bugs.
- Applications that come with unwanted programs. Some
applications come with additional software that you may not really want
but is installed by default. Normally this is only annoying and may
slightly slow your system down when it boots because some ot these items
will load every time you start your computer.
- Adware - Most adware comes with programs that may be purchased
or downloaded for free on the internet. Adware will cause advertising
popups to appear nn your computer. Besides being annoying, they will
slow your ability to access the internet. Many times these programs
will download other ad programs. These programs are very difficult to
remove from your system because they are usually hidden on your system
very well. Many times it requires an expert to remove these programs
but later I will give you some tips on how you can either remove them or
render them ineffective, but to be able to do this you must have
reasonable knowledge aboutyour system. There are some programs written
to remove adware programs which I will discuss later.
- Spyware - This usually comes with some free programs and it
will monitor your internet activity and send information to some
corporation. This type of program is not normally seriously harmful but
most people do not want to have their activities monitored. There are
also programs to remove spyware but it is best to not install it in the
first place.
If you do your research before installing applications you will avoid
most problem applications. It is best to ask your IT support personnel
about an application before you install it. In fact many corporate IT
policies are set so users cannot install programs on their systems.
This is because installation of the wrong programs on corporate systems
can jeopardize computer security for the entire organization.
Application Files
Applications have a variety of files they use for three basic purposes.
- Executable files
- Configuration files
- Data files used by the user such as Microsoft Word® document files
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