File Type and Extension

Unit 2 Summary

File Type and Extension

A file’s type is simply what a file contains. It could be either a program or data. The file type is usually closely linked to the file’s extensions. “File type” is sometimes used in a sense that is virtually synonymous with “file extension.”

There are thousands of file extensions in use with many more created every year. It is not practically to discuss every type of file extension, but there are some that are very common and worth knowing about.

Executable Files
.BAT / DOS batch files
.EXE / DOS and Windows programs
Text Files
.DOC / Documents created with Microsoft Word and WordPad
.PDF / Adobe Acrobat files
Graphics Files
.BMP / Windows bitmaps
.GIF / Graphics Interchange format (compressed graphics)
.JPEG / Joint Photographic Experts Group
Multimedia (audio & video)
.AVI / Windows animation files
.MP3 / MP3 sound files
.WAV / Windows sound files
Others
.PPT / Microsoft PowerPoint
.TMP / Temporary files (usually found in the Windows Temp folder)
.XLS / Microsoft Excel
.ZIP / Compressed archives (created with WinZip, PKZIP, or other application)

Operating System(OS)

An operating system (OS) is a software program that manages the hardware and software resources of a computer. The OS performs basic tasks, such as controlling and allocating memory, prioritizing the processing of instructions, controlling input and output devices, facilitating networking, and managing files.

The early computers did not have operating systems and were built to perform a series of single tasks,punch cards/tape were used to give operating instructions. Command Line Interface (or CLI) operating systems can operate using only the keyboard forinput. The user types in the command and the computer follows the imbedded instructions for the task. Modern OS's use a mouse for input with a Graphical User Interface (GUI). Users can simply point and click and icon and the computer follows the imbedded instructions for the task.

4 Common Operating System

1. DOS – an acronym for Disk Operating System, a Command Line Interface (CLI), which was used by several OSs.
2. Windows – developed by Microsoft Corporation featured one of the first Graphical User Interface (GUI). It soon dominated the PC market, approximately 90 percent of PCs run some version. The first version of Windows, released in 1985, was simply a GUI offered as an extension of Microsoft’s existing disk operating system, or MS-DOS. Based in part on licensed concepts that Apple Inc. had used for its Macintosh System Software, Windows for the first time allowed DOS users to visually navigate a virtual desktop, opening graphical “windows” displaying the contents of electronic folders and files with the click of a mouse button, rather than typing commands and directory paths at a text prompt. Subsequent versions introduced greater functionality, including native Windows File Manager, Program Manager, and Print Manager programs, and a more dynamic interface. Microsoft also developed specialized Windows packages, including the networkable Windows for Workgroups and the high-powered Windows NT, aimed at businesses. The 1995 consumer release Windows 95 fully integrated Windows and DOS and offered built-in Internet support, including the World Wide Web browser Internet Explorer. With the 2001 release of Windows XP, Microsoft united its various Windows packages under a single banner, offering multiple editions for consumers, businesses, multimedia developers, and others. Windows XP abandoned the long-used Windows 95 kernel (core software code) for a more powerful code base and offered a more practical interface and improved application and memory management. The highly successful XP standard was succeeded in late 2006 by Windows Vista, which experienced a troubled rollout and met with considerable marketplace resistance, quickly acquiring a reputation for being a large, slow, and resource-consuming system. Responding to Vista’s disappointing adoption rate, Microsoft developed Windows 7, an OS whose interface was similar to that of Vista but was met with enthusiasm for its noticeable speed improvement and its modest system requirements.
3. Mac – developed by Apple Inc. and introduced in 1984 to run the company’s Macintosh line of personal computers (PCs). The Macintosh heralded the era of graphical user interface (GUI) systems, and it inspired Microsoft Corporation to develop its own GUI, the Windows OS.Apple’s marketing for the introduction of the Macintosh focused heavily on its operating system’s intuitive ease of use. Unlike virtually all other contemporary PCs, the Mac OS (initially designated simply System Software, with a version number appended) was graphically based. Rather than typing commands and directory paths at text prompts, users moved a mouse pointer to visually navigate the Finder—a series of virtual folders and files, represented by icons. Most computer operating systems eventually adopted the GUI model. In the 1980s Apple made an agreement allowing Microsoft to use certain aspects of the Mac interface in early versions of Windows. However, except for a brief period in the 1990s, Mac OS has never been licensed for use with computers made by manufacturers other than Apple.Later releases introduced features such as Internet file sharing, network browsing, and multiple user accounts. In 1996 Apple acquired rival NeXT Computers, which was founded by Steven Jobs after his departure from Apple, and in 2001 the company rolled out Mac OS X, a major redesign based on both the NextStep system and Apple’s most recent OS release. OS X ran on a UNIX kernel (core software code) and offered technical advances such as memory protection and preemptive multitasking, along with a more versatile Finder, an elegant-looking interface called Aqua, and a convenient graphical “Dock” bar for launching frequently used applications. Updates to OS X added features such as automated backups and a “Dashboard” manager for small, handy applications called widgets.
4. Unix/Linux – multiuser computer operating system. UNIX is widely used for Internet servers, workstations, and mainframe computers. UNIX was developed by AT&T Corporation’s Bell Laboratories in the late 1960s as a result of efforts to create a time-sharing computer system. In 1969 a team led by computer scientists Ken Thompson and Dennis Ritchie created the first version of UNIX on a PDP-7 minicomputer, which was chosen mainly because of Thompson’s familiarity with the system from his hobby work on it. UNIX was quickly adapted for another computer, and the team ported (modified) it to the PDP-11 by late 1970. This would be the first of many ports of UNIX. Thompson left Bell Laboratories for a while and taught a course on UNIX at the University of California at Berkeley in the mid-1970s. Students and professors there further enhanced UNIX, eventually creating a version of UNIX called Berkeley Software Distribution (BSD). Work at AT&T also continued, leading to the 1983 release of a new version of UNIX called System V. These versions were later joined by UNIX versions created by Sun Microsystems, Inc., and Silicon Graphics, Inc., among other companies, and continued development kept UNIX on pace with improvements in computer technology. UNIX served as the inspiration for free open-source operating systems such as Linux and FreeBSD, and it is the basis for Apple Inc.’s Mac OS X. The main features of UNIX—its portability (the ability to run on many different systems), multitasking and multiuser capabilities, and its extensive library of software—make it as relevant and useful today as it was in 1969.

Microcomputer

Microcomputer is an electronic device with a microprocessor as its central processing unit (CPU). Microcomputer was formerly a commonly used term for personal computers, particularly any of a class of small digital computers whose CPU is contained on a single integrated semiconductor chip. Thus, a microcomputer uses a single microprocessor for its CPU, which performs all logic and arithmetic operations. The system also contains a number of associated semiconductor chips that serve as the main memory for storing program instructions and data and as interfaces for exchanging data of this sort with peripheral equipment—namely, input/output devices (e.g., keyboard, video display, and printer) and auxiliary storage units. Smaller microcomputers first marketed in the 1970s contain a single chip on which all CPU, memory, and interface circuits are integrated.

As large-scale integration and then very-large-scale integration have progressively increased the number of transistors that can be placed on one semiconductor chip, so the processing capacity of microcomputers using such single chips has grown commensurately. During the 1980s microcomputers came to be used widely in other applications besides electronic game systems and other relatively simple computer-based recreations. Increasingly powerful microcomputers began to be used in personal computer systems and workstations, for instance. High-performance microcomputer systems are used widely in business, in engineering, in “smart” or intelligent machines employed in the factory and office, and in military electronics systems.

In the early 1990s, small computers that fit in a pocket yet provide the power of a desktop personal computer were introduced. These pocket, or palm-sized, computers, commonly known as personal digital assistants (PDAs), are distinguished by their high portability, enhanced performance, and low cost. Similarly, microprocessors began finding their way into cellular telephones and portable MP3 music players. As personal computers started including multiple processors in the 2000s, microcomputer began to be relegated to descriptions of small “embedded” computers found in various electronic devices.

Basic Blocks of the Microcomputer
System Bus
Microprocessor / ROM / RAM / Input / Output
CPU / Memory Unit / I/O Unit

Vocabulary

Digital Literacy / Having current knowledge and understanding of computers, mobile devices, the Internet, and related technologies. /
Computer / An electronic device, operating under the control of instructions stored in its own memory. /
Peripheral / Devices used to enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator or, in some cases, a machine controlled by the computer. Commonly divided into three kinds: input devices, output devices, and storage devices
User / Anyone who interacts with a computer or mobile device, or utilizes the information it generates. /
Smartphone / Internet-capable phone that typically communicate wirelessly with other devices or computers. /
Input Device / Any hardware component that allows the user to enter data and instructions into a computer or mobile device. /
CPU / Central Processing Unit - computer component responsible for interpreting and executing most of the commands from the computer's other hardware and software /
RAM / Random-Access Memory, computer main memory in which specific contents can be accessed (read or written) directly by the CPU in a very short time regardless of the sequence in which they were recorded. /
Output Device / Any hardware component that conveys information from a computer or mobile device to one or more people. /
Storage Device / Records and/or retrieves items to and from storage media.
Cloud Storage / Internet service that provides storage to computer users. /
Internet / Worldwide collection of computer networks that provides society with global information and instant communication. /
ISP / Internet Service Providers- businesses that offer access to the Internet for free or for a fee. /
World Wide Web / A widely used Internet service. /
Webpage / Electronic document on the web that can contain text, graphics, audio, or video. /
Web Server / A computer that delivers requested webpages to your computer or mobile device. /
Browser / Software that enable users with an Internet connection to access and view webpages on a computer or mobile device. /
Search engine / Software that finds websites, webpages, images, videos, news, maps, and other information related to a specific topic. /
Malware / Or malicious software, is software that acts without a user’s knowledge and deliberately alters the computer’s and mobile device’s operations.
Green computing / Reduce the electricity consumed and environmental waste generated when using a computer. /
Software / Or program, consists of a series of related instructions, organized for a common purpose, that tells the computer what tasks to perform and how to perform them. /
Operating System / Set of programs that coordinates all the activities among computer or mobile device hardware. /
Application Software / Programs designed to make users more productive and/or assist them with personal tasks. /
Network / Collection of computers and devices connected together, often wirelessly, via communications devices and transmission media. /