7.Givedefinitionto Userinterface

User interface is visual part of computer application or operating system through which a user interacts with a computer or a software. It determines how commands are given to the computer or the program and how information is displayed on the screen. Two main types of user interfaces are :Command Line Interface (CLI) and Graphical User Interface (GUI)

Command Line Interface allows the user to interact directly with the computer system by typing single commands into the interface and receiving a reply in the same way.

Command line interface (CLI) is a text-based interface. After receiving the command, the CLI processes it accordingly and shows the output/result on the same screen; command line interpreter is used for this purpose. Its working mechanism is very easy, but it is not user friendly. CLI is an older method for interacting with applications and operating systems and is used to perform specific tasks required by users.

Nearly all software programs have a graphical user interface, or GUI. This means the program includes graphical controls, which the user can select using a mouse or keyboard. A typical GUI of a software program includes a menu bar, toolbar, windows, buttons, and other controls. The Macintosh and Windows operating systems have different user interfaces, but they share many of the same elements, such as a desktop, windows, icons, etc. These common elements make it possible for people to use either operating system without having to completely relearn the interface.

8.Describe Databases systems

A database system is a definition of the structure and relationship between stored data, databases, users and the hardware or operating system used for the storage. A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data. A DBMS makes it possible for end users to create, read, update and delete data in a database. The DBMS manages three important things: the data, the database engine that allows data to be accessed, locked and modified -- and the database schema, which defines the database’s logical structure. These three foundational elements help provideconcurrency, security, data integrity and uniform administration procedures.The most advanced and highly popular type of DBMS is the relational database management system Access 2007, Oracle, Microsoft SQL Server, MySQL. There are General-purpose and special-purpose databases.

Examples of Database Applications

The following are examples of database applications:

• computerized library systems;

• automated teller machines;

• flight reservation systems;

• computerized parts inventory systems.

9. Givedefinitionto Computernetworks

A computer network is a collection of computers and devices connected via communication devices and transmission media.

The main purpose of the network - a convenient and fast data exchange (of information) between devices.

Network components:

- End Devices - End Device

- Network Media (medium) - Network environment.

• The network devices that people are most familiar with are called end devices. These devices form the interface between the human network and the underlying communication network. Someexamplesofenddevicesare:

• Computers (work stations, laptops, file servers, web servers)

• Networkprinters

• VoIPphones

• Securitycameras

Mobile handheld devices (such as wireless barcode scanners, PDAs

• Intermediary Devices network component or intermediate device is such a device that combine endpoints in local (or global) data network.

For intermediate devices include hubs (hubs), switches (switches, switches), routers (routers, routers), modems (modems), wireless access point (Wireless Access Point) and firewalls (firewalls, brendmauers).

Network Media - is a metal wire (copper twisted pair telephone cable), glass (glass), or even "air” (Bluetooth, Wi-Fi, 3G, LTE). By "air" shall mean the data transmission medium without wires, that is "wireless."

• When we go to the website, we (or rather, our browser) first sends a request to a web server where you store the files of the requested site, and have a special service (program the HTTP server) processes the request and sends us back the web page file which (web page) and we will see in the browser.

Services: Web server, mail-server, ftp-server.

Processes, unlike services are invisible to us, but they (the process) is much more important for us and our network. This process works day and night on the routers, switches, wireless access points and other network equipment.

Processes: special service network processes running on network equipment.

Local-area network (LAN)A network that connects a relatively small number of machines in a relatively close geographical area

Types of Networks

Various configurations, called topologies, have been used to administer LANs

• Ring topology A configuration that connects all nodes in a closed loop on which messages travel in one direction

• Star topology A configuration that centers around one node to which all others are connected and through which all messages are sent

• Bus topology All nodes are connected to a single communication line that carries messages in both directions

• Wide-area network (WAN) A network that connects two or more local-area networks over a potentially large geographic distance

Often one particular node on a LAN is set up to serve as a gateway to handle all communication going between that LAN and other networks

Communication between networks is called internetworking

The Internet, as we know it today, is essentially the ultimate wide-area network, spanning the entire globe

• Metropolitan-area network (MAN) The communication infrastructures that have been developed in and around large cities