Topic 2: System software

(a) Describe the purpose of operating systems.

-To handle the resource allocation
-Access protection of the hardware.
-Enables the computer hardware to communicate and operate with the computer software.

(b) Describe the characteristics of different types of operating systems and their uses.

-Batch processing
is carried out from beginning to end without user interaction. It allows sharing of computer resources among many users and programs.

-Real-time,
i. They have to support application programs which are non-sequential in nature, i.e. programs which do not have a START – PROCESS – END structure;

ii. They have to deal with a number of events which happen in parallel and at unpredictable moments in time (for example, a user clicking a mouse button);

iii. They have to carry out processing and produce a response within a specified interval of time;

iv. Some systems are safety-critical, meaning they must be fail-safe and guarantee a response within a specified time interval.

-Single-user,
is a mode in which a multiuser computer operating system boots into a single superuser. It is mainly used for maintenance of multi-user environments such as network servers. Some tasks may require exclusive access to shared resources and also for security purposes.

-Multi-user,
which allows more than user to use and access the computer. For examples, XBOX, PS 3.

-Multi-tasking
which allow more than one program to run at a time. for example, a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task. Multitasking solves the problem by scheduling which task may be the one running at any given time, and when another waiting task gets a turn.

-Network systems
A network operating system is required when a number of computers are connected together in a network which allowing any user with the appropriate access rights to use software stored on the network’s file server, and to store data either on the file server or on a local hard or floppy disk.


(c) Identify a range of applications requiring batch processing and a range of applications in which a real time response is required.

-Batch processing eg. Credit card billing, calculating water bill, payroll system. Payroll system, Examination system and billing system.

-Real time processing Eg. Computer games, sensors, flight simulator. Robotics, manufacturing, special military applications.


(d) Describe different types of user interface:

-Forms is enter data step by step and store the data at database. A form interface has a set of input fields that allow text and numbers to be entered. Every fields contain data validation which is to check either the data entered is correct or not such as validating the IC number. The example of forms is online ordering system.

-Menus: Menu-driven systems offer the user a list of options from which they can choose. For example, A GUI uses windows, icons, and menus to carry out commands such as opening files, deleting files, moving files, etc.

-Natural language: This kind of interface seeks to allow you to instruct the computer by simply talking to it. This is called a "Natural Language Interface". For example, we ask for a direction where to go and the computer automatically show where the direction is.

-Command line: command line interface allows the user to interact with the computer by typing commands into the command interface. The most familiar operating system to have a command line interface is the old DOS. DOS, which stands for Disk Operating System, is an example of a command-driven user interface. Another common operating system that makes use of the command line is Unix (although this also has many graphics interfaces as well).

Suggesting the characteristics of user interfaces which make them appropriate for use by different types of user.

-Enables the user to interact with the files on computer, and the interface that enables the user to interact with players, characters and other objects in a game.

(e) Describe the purpose of a range of utility software, e.g. disk formatting, file handling, hardware drivers, file compression and virus checkers.

-Utility software are designed to help analyze, configure, optimize and , maintain the computer.
-Disk formatting: to divide up the surface of a disk into move easily manageable sectors.
-File handling: to manage the files that are store on a computer system.
-Hardware drivers: used to control communication between computer and peripherals.
-File compression: reduces size of file without the lost of any detail.
-Virus checker: used to check any files on or entering the system for viruses.