DEFINITION OF OPERATING SYSTEM
An operating system is a set of programs that schedule tasks, allocates storage and presents a default interface to the user between applications. Many of the first operating systems were device-dependent and proprietary.
The functions of the operating systems are:
- starting a computer
- providing a user interface
- managing data and programs
- managing memory
- configuring devices
A device-dependent program is the one that runs only on a specific make of a computer.
Proprietary software is privately owned and limited to a specific vendor or computer.
PC PLATFORM OPERATING SYSTEMS
There are various types of operating system used on different platforms. The examples of operating systems used on PC platforms or IBM compatible computers are:
- Disk Operating System (DOS)
- Microsoft Windows XP
It is necessary for computer manufacturers to produce unique software versions for each platform available in the market. For instance, the Apple Macintosh, PC-compatibles, and Sun SPARC-Stations are all different platforms.
DOS is an acronym for Disk Operating System. Microsoft developed DOS in the early 1980s for personal computers. DOS used a command line interface when Microsoft first developed it. It is a closed source software.
Microsoft Windows XP’s operating environment is a Graphical User Interface (GUI). It is a closed source software.
APPLE PLATFORM OPERATING SYSTEMS
The operating systems used on Apple platforms are:
- Mac OS
- Mac OS X
Mac OS was the first commercially successful graphical user interface released in 1984. It is a closed source software and are targeted for use with home desktops and workstations.
Mac OS X is a multitasking operating system and it is the latest version of the Macintosh operating system released in 2001. Mac OS X is targeted for use with home desktops, workstations and servers. It also has better security protection compared to Mac OS, for example the integrated firewall utility.
CROSS-PLATFORM OPERATING SYSTEMS
Cross-platforms operating systems are:
- UNIX
- LINUX
UNIX is a multitasking operating system developed in the early 1970s by scientists at the Bell Laboratories. Some versions of UNIX have a command line interface but most versions of UNIX offer a graphical user interface.
Linux is a popular, free, UNIX-like graphical user interface operating system. It is an open source software. Linux follows the Free Software Foundation's radical licensing model, which provides a great deal of liberty to those that interact with Linux technology.
Although Linux runs on many kinds of equipment, it is best known for its support of IBM-Intel PC-based hardware.
USER INTERFACES
The user interface is the part of an operating system that you see and interact with and by which users and programs communicate with each other.
The importance of user interfaces are:
- to assist users interacting with a software
- to control how a user enters data and instructions
- to control how information is displayed
COMMAND-LINE USER INTERFACE
The command-line user interface requires a user to type commands or press special keys on the keyboard to enter data and instructions that instruct the operating system what to do. It has to be typed one line at a time.
The command-line user interface is difficult to use because it requires exact spelling, syntax or a set of rules of entering commands and punctuation.
We must observe the complicated rules of syntax that specify exactly what you can type in a given place.For example, if we want to rename a filename from ABC.txt to DEF.txt we use the following command.
The command-line user interface also requires memorisation. It is also easy to make a typing mistake. The advantage of command-line interface is, it helps the user to operate the computer quickly after memorizing the keywords and syntax.
MENU DRIVEN INTERFACE
Menu-driven user interface enables the user to avoid memorizing keywords such as copy, paste and syntax. On-screen, menu-driven interface provide menus as means of entering commands. It shows all the options available at a given point in a form of text-based menu. Menu-driven user interfaces are easy to learn.
GRAPHICAL USER INTERFACE (GUI)
Graphical user interface makes use of the computer’s graphics capabilities to make the operating system and programs easier to use, which is also called ‘user-friendly’. On today’s PCs and Macintoshes, GUIs are used to create the desktop that appears after the operating system finishes loading into memory.
We can easily differentiate the interfaces between Mac OS, Windows XP or Linux by looking at their desktops. Graphical user interface interact with menus and visual images such as buttons, icons and other graphical objects to issue commands.
On the desktop, we can initiate many actions by clicking icons that represent computer resources such as files, programs and network connections. Graphical user interface is commonly used and has become a standard.
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