Notes

** Computer software **, or just **software**, is a collection of [|computer programs] and related [|data] that provides the instruction code for telling a [|computer] hardware what to do and how to do it. Software refers to one or more computer programs and data held in the storage of the computer for some purposes. In other words, software is a set of //programs, procedures, algorithms// and its //documentation// concerned with the operation of a data processing system. Program software performs the [|function] of the [|program] it implements, either by directly providing [|instructions] to the computer hardware or by serving as input to another piece of software.
 * __ COMPUTER SOFTWARE __**

__ Types of software __
Software can be divided into twoparts:
 * 1) System software and
 * 2) Application

System software
[|System software] provides the basic functions for computer usage and helps run the computer hardware and system. System software is responsible for managing a variety of independent hardware components, so that they can work together harmoniously. It includes a combination of the following:
 * 1)  [|Operating systems]
 * 2)  [|Translators]
 * 3)  [|Utilities] **//Programs or tool programs//**

Operating system
An **operating system** (**OS**) is a set of [|programs]  that manage [|computer hardware]  resources and provide common services for [|application software] . The operating system is the most important type of [|system software]  in a computer system. A user cannot run an application program on the computer without an operating system, unless the application program is self booting.

Types of Operating system
When only a single program is allowed to run at a time, the system is grouped under a single-tasking system. However, when the operating system allows the execution of multiple tasks at one time, it is classified as a multi-tasking operating system. Multi-tasking can be of two types: pre-emptive or co-operative. In pre-emptive multitasking, the operating system slices the CPU time and dedicates one slot to each of the programs. Unix-like operating systems such as Solaris and Linux support pre-emptive multitasking, as does AmigaOS. Cooperative multitasking is achieved by relying on each process to give time to the other processes in a defined manner. [|16-bit]  versions of Microsoft Windows used cooperative multi-tasking. [|32-bit]  versions, both Windows NT and Win9x, used pre-emptive multi-tasking. Mac OS prior to OS X used to support cooperative multitasking.
 * 1) **Real-time** : A [|real-time operating system] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> is a multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behavior. The main objective of real-time operating systems is their quick and predictable response to events. They have an event-driven or time-sharing design and often aspects of both. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
 * 2) **Multi-user:** <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">A multi-user operating system allows multiple users to access a computer system concurrently. Time-sharing system can be classified as multi-user systems as they enable a multiple user access to a computer through the sharing of time. Single-user operating systems, as opposed to a multi-user operating system, are usable by a single user at a time. Being able to use multiple accounts on a Windows operating system does not make it a multi-user system. Rather, only the network administrator is the real user. But for a Unix-like operating system, it is possible for two users to login at a time and this capability of the OS makes it a multi-user operating system.
 * 3) **Multi-tasking vs. Single-tasking**
 * 1) **Multi-tasking vs. Single-tasking**
 * 1) **Distributed:** <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">A distributed operating system manages a group of independent computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they make a distributed system.
 * 2) **Embedded:** <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px;">[|Embedded] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources. They are very compact and extremely efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems.

Examples of operating system
<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Windows, MS DOS, Linus, Macintosh, etc. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Windows operating system is the most common OS and there are various versions from Windows 95 to Windows 7.

A Translators
<span style="font-family: 'Times New Roman','serif'; font-size: 19px;">A **Translator** is a computer program that translates one programming language instruction(s) into another programming language instruction(s) without the loss of original meaning.

Types of Translators
** Compiler ** **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;">: **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> If the translator translates a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|high level language] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> into an <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|assembly] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> or <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|machine language] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> it is called a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|compiler] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. Examples include <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Ada] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|ALGOL] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|BASIC] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|COBOL] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|FORTRAN] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> etc ** Interpreter ** <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">: If the translator translates a high level language into an intermediate code which will be immediately executed it is called <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|interpreter] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. Examples include <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|APL] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|ASP] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|CYBOL] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|LISP] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Smalltalk] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|PHP] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|PERL] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. ** Decompiler ** **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;">: **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> If the translator translates target/machine code to source language it is called a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Decompiler] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. Example: <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|DCC] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Boomerang Decompilers] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Reverse Engineering Compiler] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> (REC). ** Assembler ** <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">: If the translator translates assembly language to machine code such kind of translator is called <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|assembler] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. Examples include <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|MASM] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|TASM] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|NASM] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|FASM] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. ** Disassemble ** <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">: If the translator translates machine code into assembly language such kind of translator is called <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Disassembler] **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. **<span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> Examples include <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|gdb] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|IDA Pro] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|OllyDbg] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">.

Utility software
**<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Utility software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> is <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|system software] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> designed to help analyze, configure, optimize or maintain a computer. A single piece of utility software is usually called a **utility** or **tool**. <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Utility software usually focuses on //how// the computer infrastructure (including the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|computer hardware] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|operating system] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">, <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|application software] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|data] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> storage) operates. Due to this focus, utilities are often rather technical and targeted at people with an advanced level of computer knowledge.

Utility software categories

 * [|**Anti-virus**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities scan for computer viruses.
 * [|**Backup**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities can make a copy of all information stored on a disk, and restore either the entire disk (e.g. in an event of <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|disk failure] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">) or selected files (e.g. in an event of accidental deletion).
 * [|**Data compression**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities output a shorter stream or a smaller file when provided with a stream or file.
 * [|**Disk checkers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> can scan the contents of a hard disk to find files or areas that are corrupted in some way, or were not correctly saved, and eliminate them for a more efficiently operating hard drive.
 * [|**Disk cleaners**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> can find files that are unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|user] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> to decide what to <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|delete] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> when their hard disk is full.
 * [|**Disk compression**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities can transparently <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|compress] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">/uncompress the contents of a disk, increasing the capacity of the disk.
 * [|**Disk defragmenters**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> can detect <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|computer files] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> whose contents are broken across several locations on the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|hard disk] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">, and move the fragments to one location to increase efficiency.
 * [|**Disk partitions**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> can divide an individual drive into multiple logical drives, each with its own file system which can be mounted by the operating system and treated as an individual drive.
 * [|**Disk space analyzers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> for the visualization of disk space usage by getting the size for each folder (including sub folders) & files in folder or drive. showing the distribution of the used space.
 * [|**Disk storage**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities
 * [|**Archive**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities output a stream or a single file when provided with a directory or a set of files. Archive utilities, unlike archive suites, usually do not include compression or encryption capabilities. Some archive utilities may even have a separate un-archive utility for the reverse operation.
 * [|**File managers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> provide a convenient method of performing routine data management tasks, such as deleting, renaming, cataloging, uncataloging, moving, copying, merging, generating and modifying data sets.
 * [|**Cryptographic**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> utilities encrypt and decrypt streams and files.
 * [|**Hex editors**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> directly modify the text or data of a file. These files could be data or an actual program.
 * [|**Memory testers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> check for memory failures.
 * [|**Network utilities**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> analyze the computer's network connectivity, configure network settings, check data transfer or log events.
 * [|**Registry cleaners**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> clean and optimize the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|Windows registry] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> by removing old registry keys that are no longer in use.
 * [|**Screensavers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> were desired to prevent <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|phosphor burn-in] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> on <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|CRT] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> and plasma <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 16px; text-decoration: none;">[|computer monitors] <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> by blanking the screen or filling it with moving images or patterns when the computer is not in use. Contemporary screensavers are used primarily for entertainment or security.
 * [|**System monitors**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> for monitoring resources and performance in a computer system.
 * [|**System profilers**]<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> provide detailed information about the software installed and hardware attached to the computer.

Application software
[|Application software] is developed to perform in any task that benefits from computation. It is a set of programs that allows the computer to perform a specific data processing job for the user. It is a broad category, and encompasses ** software ** of many kinds, including the [|internet browser].

Types of Application Software:
**<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Word Processing Software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: Allows users to create, edit a document. Example: MS Word, Word Pad etc. **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Spreadsheet Software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: performs calculations, analyze information, and visualize data in spreadsheet. Example: MS Excel, Lotus1-2-3 etc. **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Database Software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: creates data bases and programs to track and manage information by using database software. Example: MS Access, MySQL, Oracle etc. **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Presentation Graphic Software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: creates and edits presentations for slide shows, meetings and web pages. Examples MS Power Point **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Multimedia Software **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: Allows users to create image, audio, video etc. Example: Real Player, Media Player etc. <span style="font-family: 'Times New Roman','serif'; font-size: 35px;">Central processing unit

<span style="font-family: 'Times New Roman','serif'; font-size: 19px;">An <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|Intel 80486DX2] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> CPU from above <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">An Intel 80486DX2 from below <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">The central processing unit (CPU) is the portion of a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|computer] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> system that carries out the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|instructions] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> of a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|computer program] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">, to perform the basic arithmetical, logical, and <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|input/output] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> operations of the system. The CPU plays a role somewhat analogous to the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|brain] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> in the computer. The term has been in use in the computer industry at least since the early 1960s. [|[1]]<span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same. <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">On large machines, CPUs require one or more <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|printed circuit boards] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. On personal computers and small workstations, the CPU is housed in a single <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|silicon chip] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> called a <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|microprocessor] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">. Since the 1970s the microprocessor class of CPUs has almost completely overtaken all other CPU implementations. Modern CPUs are large scale <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|integrated circuits] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> in packages typically less than four centimeters square, with hundreds of connecting pins. <span style="font-family: 'Times New Roman','serif'; font-size: 19px;">Two typical components of a CPU are the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|arithmetic logic unit] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> (ALU), which performs arithmetic and logical operations, and the <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|control unit] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> (CU), which extracts instructions from <span style="color: windowtext; font-family: 'Times New Roman','serif'; font-size: 19px; text-decoration: none;">[|memory] <span style="font-family: 'Times New Roman','serif'; font-size: 19px;"> and decodes and executes them, calling on the ALU when necessary. = Find all you need to know about the most common types of files on the internet. Our free Windows tutorials demystify zip, pdf and other types of files = Quick links:-<span style="font-family: 'Calibri','sans-serif';">[|Common types of files in Windows][|Pitfall - Hidden file extensions!][|What are Zip files? / 7Zip tutorials][|What are pdf/Acrobat files?][|Comment on this article] Now that you are a little more confident using your PC, thanks to our <span style="font-family: 'Times New Roman','serif';">[|Windows XP basics free Windows tutorials], <span style="font-family: 'Times New Roman','serif';">[|free Windows Vista tutorials] or our <span style="font-family: 'Times New Roman','serif';">[|Windows 7 tutorials] , it is time to move on to some more advanced topics. Don't worry though, nothing we cover in these free Windows tutorials is any more complicated than the videos you have already covered. Once you are familiar with the material presented here you will be able to use your PC and the internet much more effectively. Common types of files in Windows and on the internet When you are working and communicating with friends, family and colleagues you are likely to come across several types of file. Windows can handle many types of files without any additional software and almost all others with additional software. The table below shows you some of the most common types of file and what to do with them:- || **<span style="color: black; font-family: 'Arial','sans-serif';">File Type ** As you can see, windows is well equipped to deal with most common types of files. These tutorials will focus on some of the more unusual types of files and how to work with them. Pitfall - Hidden file extensions! One of my least favourite features of Windows is its unhelpful "Hide file extensions" option. A file extension is the three or more letters following the dot on the end of a file name. For example, the file extension of "myfiles.zip" is ".zip". We covered the "hide file extension of known file types" option in other free Windows tutorials, specifically <span style="font-family: 'Times New Roman','serif';">[|Windows XP basics tutorial 6] and <span style="font-family: 'Times New Roman','serif';">[|Windows 7 basics tutorial 9]. Windows Vista users may wish to watch this video too, since understanding the concept of "hidden file extensions" is important. Basically, Windows has the option of hiding the file extension part of a file name. For example, a zip file on your computer may be named "myfiles.zip". If you have the "Hide file extensions" option turned on, Windows explorer will show this file as "myfiles". We are not sure exactly why the designers of Windows made it this way, our best guess was it was an attempt to make things appear less complicated for beginners. Above - Windows shows us a file called myfiles.zip, below - exactly the same file and folder but with the "hide file extensions of known file types" option turned on. These files are 100% identical, don't get caught out if you use this option! Look at the picture below, with the "hide file extensions" option turned on, it looks as though we can have files with the same name in the same folder! Look closely though and you can see the icons are different. The actual names of these files are myfiles.zip, myfiles.txt and myfiles.bmp, but again Windows is hiding those file extensions from us! Now you understand this somewhat confusing state of affairs, you have mastered one of the most common pitfalls when working with files in Windows. This one still catches us out from time to time, so beware! What are Zip files? When transporting a large number of files across the internet, by e-mail the web or any other means, it is not usually convenient to send them one by one. More experienced computer users usually prefer to use Zip files. A Zip file acts like a container, or perhaps a suitcase, letting you put lots of smaller files inside it. Furthermore, Zip files use a special software technique called "compression" which shrinks the size of the files you store to minimise the time it takes to transmit them across the internet. Unlike your holiday suitcase though, squashing more things inside a zip file won't ever cause damage to them. Windows XP and Windows Vista can both open Zip files automatically, just double click on a Zip file to inspect its contents. You may have already been working with Zip files without even knowing it, since clicking on a Zip file simply displays its contents in a Windows Explorer window. Wouldn't it be great to create our own Zip files, to send files and photographs to our friends across the internet? Windows Explorer comes with some basic support for creating Zip files, if you want to make your own Zip files in Explorer, take a look at <span style="font-family: 'Times New Roman','serif';">[|this tutorial]. Want a more powerful Zip utility with better compression and support for other archive formats? Then you need the superb free 7-Zip package. Check out our free Windows tutorials on 7-Zip:-<span style="font-family: 'Times New Roman','serif';">[|7-Zip tutorial 1 - Installing 7-Zip][|7-Zip tutorial 2 - Extracting files][|7-Zip tutorial 3 - Making your own zip files] PC acrobatics?! - What are pdf/Acrobat files? PDF files are used for a wide range of digitally stored documentation Nothing to do with acrobatics, Adobe Acrobat/pdf files are very common on the internet and in business. In the days before fast, powerful multimedia computers were commonplace, chances are you would buy a computer program from a store and receive a printed instruction manual. Nowadays more and more companies are saving money by including manuals in pdf format. Pdf files are also used for forms and receipts and sometimes also letters and business correspondence. Unlike web pages or word processor documents, pdf files are designed to look identical on any machine that can open them and in the case of instruction manuals or other documents, identical to the paper hard-copy they are based on. While Windows cannot open pdf files without extra software, the required software is free to download and easy to install. Visit <span style="font-family: 'Times New Roman','serif';">this page to download Acrobat Reader and then install it to start viewing pdf documents on your PC.
 * **<span style="color: black; font-family: 'Arial','sans-serif';">Extension ** || **<span style="color: black; font-family: 'Arial','sans-serif';">What is it? ** || **<span style="color: black; font-family: 'Arial','sans-serif';">Need extra s/w to view? ** ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Acrobat || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.pdf || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Text and/or picture document || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Yes ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Bitmap || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.bmp || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Picture || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Document || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.doc || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Microsoft Word Document || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No* ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Excel sheet || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.xls || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Microsoft Excel Document || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Yes ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Executable || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.exe || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">A computer program || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">GIF || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.gif || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Picture, often a graphic on a website || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">JPEG || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.jpg || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Picture, usually a photograph || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">PNG || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.png || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Picture, often a graphic on a website || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Powerpoint || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.pps || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">A Powerpoint presentation || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Yes ||
 * <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">Zip archive || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">.zip || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">A collection of compressed files || <span style="color: black; display: block; font-family: 'arial','sans-serif'; text-align: center;">No ||
 * Microsoft word documents can usually be opened with Wordpad, the free word processor built into Windows. However certain Microsoft word documents which use advanced features may not open correctly with Wordpad.