i)Hardware- Hardware is a general term that refers to the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware.
ii)Software- Computer software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system.
iii)Input device- An Input device is any piece of computer hardware equipment used to provide data and control signals to an information processing system (such as a computer). Input and output devices make up the hardware interface between a computer and the user or external world.
iv)Storage device- A storage device is a device used for storing something.
v)Output device- An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world.
Monday, March 31, 2008
Monday, March 17, 2008
The Mode of Operation
MULTIPROCESSING
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them.[1] There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined (multiple cores on one die, multiple chips in one package, multiple packages in one system unit, etc.).
Multiprocessing sometimes refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant. However, the term multiprogramming is more appropriate to describe this concept, which is implemented mostly in software, whereas multiprocessing is more appropriate to describe the use of multiple hardware CPUs. A system can be both multiprocessing and multiprogramming, only one of the two, or neither of the two.
MULTITASKING
In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of 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. The act of reassigning a CPU from one task to another one is called a context switch. When context switches occur frequently enough the illusion of parallelism is achieved. Even on computers with more than one CPU (called multiprocessor machines), multitasking allows many more tasks to be run than there are CPUs.
BATCH PROCESSING
Batch processing is execution of a series of programs ("jobs") on a computer without human interaction.
Batch jobs are set up so they can be run to completion without human interaction, so all input data is preselected through scripts or commandline parameters. This is in contrast to "online" or interactive programs which prompt the user for such input.
Batch processing has these benefits:
-It allows sharing of computer resources among many users,
-It shifts the time of job processing to when the computing resources are less busy,
-It avoids idling the computing resources with minute-by-minute human interaction and supervision,
-By keeping high overall rate of utilization, it better amortizes the cost of a computer, especially an expensive one.
REAL-TIME PROCESSING
Real-time processing is a process in which when any changes occur in the database, it will be updated instantly. For example, in an airline reservation counter, when people have booked the seats, it will be updated immediately in the database that those seats cannot be taken anymore.
MULTI-USER
Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term "multitasking" is more common in this context.
reference- www.wikipedia.org
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them.[1] There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined (multiple cores on one die, multiple chips in one package, multiple packages in one system unit, etc.).
Multiprocessing sometimes refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant. However, the term multiprogramming is more appropriate to describe this concept, which is implemented mostly in software, whereas multiprocessing is more appropriate to describe the use of multiple hardware CPUs. A system can be both multiprocessing and multiprogramming, only one of the two, or neither of the two.
MULTITASKING
In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of 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. The act of reassigning a CPU from one task to another one is called a context switch. When context switches occur frequently enough the illusion of parallelism is achieved. Even on computers with more than one CPU (called multiprocessor machines), multitasking allows many more tasks to be run than there are CPUs.
BATCH PROCESSING
Batch processing is execution of a series of programs ("jobs") on a computer without human interaction.
Batch jobs are set up so they can be run to completion without human interaction, so all input data is preselected through scripts or commandline parameters. This is in contrast to "online" or interactive programs which prompt the user for such input.
Batch processing has these benefits:
-It allows sharing of computer resources among many users,
-It shifts the time of job processing to when the computing resources are less busy,
-It avoids idling the computing resources with minute-by-minute human interaction and supervision,
-By keeping high overall rate of utilization, it better amortizes the cost of a computer, especially an expensive one.
REAL-TIME PROCESSING
Real-time processing is a process in which when any changes occur in the database, it will be updated instantly. For example, in an airline reservation counter, when people have booked the seats, it will be updated immediately in the database that those seats cannot be taken anymore.
MULTI-USER
Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term "multitasking" is more common in this context.
reference- www.wikipedia.org
Tuesday, March 11, 2008
5) Utility Softwares
two examples of it-
Disk defragmenters - Examples include a Disk defragmenter which can detect computer files whose contents have been stored on the hard disk in disjointed fragments, and move the fragments together to increase efficiency; a Disk checker 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; a Disk cleaner can find files that unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the user to decide what to delete when their hard disk is full.
System Profilers - A System profiler can provide detailed information about the software installed and hardware attached to the computer. Backup software can make a copy of all information stored on a computer, and restore either the entire system (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion). Disk compression software can transparently compress the contents of the hard disk, in order to fit more information to the drive.
Disk defragmenters - Examples include a Disk defragmenter which can detect computer files whose contents have been stored on the hard disk in disjointed fragments, and move the fragments together to increase efficiency; a Disk checker 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; a Disk cleaner can find files that unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the user to decide what to delete when their hard disk is full.
System Profilers - A System profiler can provide detailed information about the software installed and hardware attached to the computer. Backup software can make a copy of all information stored on a computer, and restore either the entire system (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion). Disk compression software can transparently compress the contents of the hard disk, in order to fit more information to the drive.
4) Operating Systems
An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. An operating system processes system data and user input, and responds by allocating and managing tasks and internal system resources as a service to users and programs of the system. At the foundation of all system software, an operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating computer networking and managing files. Most operating systems come with an application that provides an interface for managing the operating system.
2 examples of OS are Windows and Macintosh.
ref- www.wikipedia.org
2 examples of OS are Windows and Macintosh.
ref- www.wikipedia.org
3) Programming Languages, compilers and interpreters
COMPILER
A compiler is a computer program (or set of programs) that translates text written in a computer language (the source language) into another computer language (the target language)
two examples of compiler are Pascal and C.
INTERPRETER
An interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language. While interpretation and compilation are the two principal means by which programming languages are implemented, these are not fully distinct categories, one of the reasons being that most interpreting systems also perform some translation work, just like compilers. An interpreter may be a program that either.
two examples of interpreter are Python and Perl.
ref- www.wikipedia.org
A compiler is a computer program (or set of programs) that translates text written in a computer language (the source language) into another computer language (the target language)
two examples of compiler are Pascal and C.
INTERPRETER
An interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language. While interpretation and compilation are the two principal means by which programming languages are implemented, these are not fully distinct categories, one of the reasons being that most interpreting systems also perform some translation work, just like compilers. An interpreter may be a program that either.
two examples of interpreter are Python and Perl.
ref- www.wikipedia.org
Monday, March 10, 2008
2) Special Purpose Applications Software
two examples-
DATABASE MANAGEMENT SYSTEM
A DBMS is a complex set of software programs that controls the organization, storage, management, and retrieval of data in a database. A DBMS includes:
-A modeling language to define the schema of each database hosted in the DBMS, according to the DBMS data model.
The four most common types of organizations are the hierarchical, network, relational and object models. Inverted lists and other methods are also used. A given database management system may provide one or more of the four models. The optimal structure depends on the natural organization of the application's data, and on the application's requirements (which include transaction rate (speed), reliability, maintainability, scalability, and cost).
The dominant model in use today is the ad hoc one embedded in SQL, despite the objections of purists who believe this model is a corruption of the relational model, since it violates several of its fundamental principles for the sake of practicality and performance. Many DBMSs also support the Open Database Connectivity API that supports a standard way for programmers to access the DBMS.
-Data structures (fields, records, files and objects) optimized to deal with very large amounts of data stored on a permanent data storage device (which implies relatively slow access compared to volatile main memory).
-A database query language and report writer to allow users to interactively interrogate the database, analyze its data and update it according to the users privileges on data.
It also controls the security of the database.
Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called subschemas. For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data.
If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases. However, it may not leave an audit trail of actions or provide the kinds of controls necessary in a multi-user organization. These controls are only available when a set of application programs are customized for each data entry and updating function.
-A transaction mechanism, that ideally would guarantee the ACID properties, in order to ensure data integrity, despite concurrent user accesses (concurrency control), and faults (fault tolerance).
It also maintains the integrity of the data in the database.
The DBMS can maintain the integrity of the database by not allowing more than one user to update the same record at the same time. The DBMS can help prevent duplicate records via unique index constraints; for example, no two customers with the same customer numbers (key fields) can be entered into the database. See ACID properties for more information (Redundancy avoidance).
GEOGRAPHICAL INFORMATION SYSTEM
A geographic information system (GIS), also known as a geographical information system or geospatial information system, is any system for capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to Earth.
In the strictest sense, it is any information system capable of integrating, storing, editing, analyzing, sharing, and displaying geographically referenced information. In a more generic sense, GIS is a tool that allows users to create interactive queries (user created searches), analyze the spatial information, edit data, maps, and present the results of all these operations. Geographic information system technology can be used for scientific investigations, resource management, asset management, environmental impact assessment, urban planning, cartography, criminology, history, sales, marketing, and logistics. For example, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business to take advantage of a previously underserved market.
ref- www.wikipedia.org
DATABASE MANAGEMENT SYSTEM
A DBMS is a complex set of software programs that controls the organization, storage, management, and retrieval of data in a database. A DBMS includes:
-A modeling language to define the schema of each database hosted in the DBMS, according to the DBMS data model.
The four most common types of organizations are the hierarchical, network, relational and object models. Inverted lists and other methods are also used. A given database management system may provide one or more of the four models. The optimal structure depends on the natural organization of the application's data, and on the application's requirements (which include transaction rate (speed), reliability, maintainability, scalability, and cost).
The dominant model in use today is the ad hoc one embedded in SQL, despite the objections of purists who believe this model is a corruption of the relational model, since it violates several of its fundamental principles for the sake of practicality and performance. Many DBMSs also support the Open Database Connectivity API that supports a standard way for programmers to access the DBMS.
-Data structures (fields, records, files and objects) optimized to deal with very large amounts of data stored on a permanent data storage device (which implies relatively slow access compared to volatile main memory).
-A database query language and report writer to allow users to interactively interrogate the database, analyze its data and update it according to the users privileges on data.
It also controls the security of the database.
Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called subschemas. For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data.
If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases. However, it may not leave an audit trail of actions or provide the kinds of controls necessary in a multi-user organization. These controls are only available when a set of application programs are customized for each data entry and updating function.
-A transaction mechanism, that ideally would guarantee the ACID properties, in order to ensure data integrity, despite concurrent user accesses (concurrency control), and faults (fault tolerance).
It also maintains the integrity of the data in the database.
The DBMS can maintain the integrity of the database by not allowing more than one user to update the same record at the same time. The DBMS can help prevent duplicate records via unique index constraints; for example, no two customers with the same customer numbers (key fields) can be entered into the database. See ACID properties for more information (Redundancy avoidance).
GEOGRAPHICAL INFORMATION SYSTEM
A geographic information system (GIS), also known as a geographical information system or geospatial information system, is any system for capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to Earth.
In the strictest sense, it is any information system capable of integrating, storing, editing, analyzing, sharing, and displaying geographically referenced information. In a more generic sense, GIS is a tool that allows users to create interactive queries (user created searches), analyze the spatial information, edit data, maps, and present the results of all these operations. Geographic information system technology can be used for scientific investigations, resource management, asset management, environmental impact assessment, urban planning, cartography, criminology, history, sales, marketing, and logistics. For example, GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, GIS might be used to find wetlands that need protection from pollution, or GIS can be used by a company to site a new business to take advantage of a previously underserved market.
ref- www.wikipedia.org
1) General Purpose applications software
two examples-
WORDPROCESSOR
wordprocessor is used for the production (including composition, editing, formatting, and possibly printing) of any sort of printable material.
SPREADSHEET
A spreadsheet is a computer application that superseded paper worksheets. It displays multiple cells that together make up a grid consisting of rows and columns, each cell containing either alphanumeric text or numeric values. A spreadsheet cell may alternatively contain a formula that defines how the contents of that cell is to be calculated from the contents of any other cell (or combination of cells) each time any cell is updated. Spreadsheets are frequently used for financial information because of their ability to re-calculate the entire sheet automatically after a change to a single cell.
ref- www.wikipedia.org
WORDPROCESSOR
wordprocessor is used for the production (including composition, editing, formatting, and possibly printing) of any sort of printable material.
SPREADSHEET
A spreadsheet is a computer application that superseded paper worksheets. It displays multiple cells that together make up a grid consisting of rows and columns, each cell containing either alphanumeric text or numeric values. A spreadsheet cell may alternatively contain a formula that defines how the contents of that cell is to be calculated from the contents of any other cell (or combination of cells) each time any cell is updated. Spreadsheets are frequently used for financial information because of their ability to re-calculate the entire sheet automatically after a change to a single cell.
ref- www.wikipedia.org
Friday, March 7, 2008
3 types of hardware and their uses
SCANNER
In computing, a scanner is a device that analyzes images, printed text, or handwriting, or an object (such as an ornament) and converts it to a digital image. Most scanners today are variations of the desktop (or flatbed) scanner. The flatbed scanner is the most common in offices. Hand-held scanners, where the device is moved by hand, were briefly popular but are now not used due to the difficulty of obtaining a high-quality image. Both these types of scanners use charge-coupled device (CCD) or Contact Image Sensor (CIS) as the image sensor, whereas older drum scanners use a photomultiplier tube as the image sensor.
Another category of scanner is a rotary scanner, used for high-speed document scanning. This is another kind of drum scanner, but it uses a CCD array instead of a photomultiplier.
Other types of scanners are planetary scanners, which take photographs of books and documents, and 3D scanners, for producing three-dimensional models of objects, but these types of scanner are considerably more expensive than other types of scanners.
Another category of scanner are digital camera scanners, which are based on the concept of reprographic cameras. Due to increasing resolution and new features such as anti-shake, digital cameras have become an attractive alternative to regular scanners. While still containing disadvantages compared to traditional scanners, digital cameras offer unmatched advantages in speed and portability.
PRINTER
A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local computer peripherals, and are attached by a printer cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.
In addition, many modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit. Printers that include non-printing features are sometimes called Multi-Function Printers (MFP) or Multi-Function Devices (MFD).
A printer which is combined with a scanner can function as a photocopier if so designed. Most MFPs include printing, scanning, and copying among their features.
Printers are designed for low-volume, short-turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given document. However, printers are generally slow devices (30 pages per minute is considered fast; and many consumer printers are far slower than that), and the cost-per-page is relatively high.
MOUSE
In computing, a mouse functions as a pointing device by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of a small case, held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.
ref- www.wikipedia.org and www.google.com
Comparisons of various webhostings
BLOGGER
Blogger is a blog publishing system. It was created by Pyra Labs, which was bought by Google in 2003.
redesign : As part of the Blogger redesign in 2006, all blogs associated with a user's Google Account are located on Google servers. Blogger claims that the service is now more reliable because of the quality of the servers.
Along with the migration to Google servers, several new features were introduced, including label organization, a drag-and-drop template editing interface, reading permissions (to create private blogs) and new Web feed options. Furthermore, blogs are updated dynamically, as opposed to rewriting HTML files.
TRIPOD
Tripod.com is a web hosting service now owned by Lycos. Originally a company aimed at offering services to college students and young adults, it was one of several sites trying to build online communities during the dot-com bubble. As such, Tripod formed part of the first wave of user-generated content.
Services : Tripod offers a variety of free and paid web hosting services including 20 megabytes of webspace and the ability to run Common Gateway Interface (CGI) scripts in Perl. In addition to basic hosting, Tripod also offers a blogging tool, a photo album manager, and the Trellix site builder for WYSIWYG page editing. In addition to its free service, Tripod also offers a variety of for-pay services including additional disk space, a shopping cart, domain names, web and POP/IMAP email.
GEOCITIES
Yahoo! GeoCities is a webhosting service founded by David Bohnett and John Rezner in late 1994 as Beverly Hills Internet (BHI).
In its original form, site users selected a "city" in which to place their webpages. The "cities" were named after real cities or regions according to their content — for example, computer-related sites were placed in "SiliconValley" and those dealing with entertainment were assigned to "Hollywood" — hence the name of the site; however, this feature has since been abandoned.
ref-www.wikipedia.org
Blogger is a blog publishing system. It was created by Pyra Labs, which was bought by Google in 2003.
redesign : As part of the Blogger redesign in 2006, all blogs associated with a user's Google Account are located on Google servers. Blogger claims that the service is now more reliable because of the quality of the servers.
Along with the migration to Google servers, several new features were introduced, including label organization, a drag-and-drop template editing interface, reading permissions (to create private blogs) and new Web feed options. Furthermore, blogs are updated dynamically, as opposed to rewriting HTML files.
TRIPOD
Tripod.com is a web hosting service now owned by Lycos. Originally a company aimed at offering services to college students and young adults, it was one of several sites trying to build online communities during the dot-com bubble. As such, Tripod formed part of the first wave of user-generated content.
Services : Tripod offers a variety of free and paid web hosting services including 20 megabytes of webspace and the ability to run Common Gateway Interface (CGI) scripts in Perl. In addition to basic hosting, Tripod also offers a blogging tool, a photo album manager, and the Trellix site builder for WYSIWYG page editing. In addition to its free service, Tripod also offers a variety of for-pay services including additional disk space, a shopping cart, domain names, web and POP/IMAP email.
GEOCITIES
Yahoo! GeoCities is a webhosting service founded by David Bohnett and John Rezner in late 1994 as Beverly Hills Internet (BHI).
In its original form, site users selected a "city" in which to place their webpages. The "cities" were named after real cities or regions according to their content — for example, computer-related sites were placed in "SiliconValley" and those dealing with entertainment were assigned to "Hollywood" — hence the name of the site; however, this feature has since been abandoned.
ref-www.wikipedia.org
Wednesday, March 5, 2008
functions of a disk formatting software
Disk formatting is the process of preparing a hard disk or other storage medium for use, including setting up an empty file system. A variety of utilities and programs exist for this task; pictured to the right is the iconic FORMAT.COM of MS-DOS and PC-DOS.
Large disks can be partitioned, divided into logical sections that are formatted with their own file systems. This is normally only done on hard disks because of the small sizes of other disk types, as well as compatibility issues.
A corrupted operating system can be reverted to a clean state by formatting the disk and reinstalling the OS, as a drastic way of combatting a software problem or malware infection. Obviously, important files should be backed up beforehand.
ref- www.wikipedia.org
Large disks can be partitioned, divided into logical sections that are formatted with their own file systems. This is normally only done on hard disks because of the small sizes of other disk types, as well as compatibility issues.
A corrupted operating system can be reverted to a clean state by formatting the disk and reinstalling the OS, as a drastic way of combatting a software problem or malware infection. Obviously, important files should be backed up beforehand.
ref- www.wikipedia.org
Comparisons of various OS
WINDOWS
Microsoft Windows is the name of several families of software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows eventually came to dominate the world's personal computer market, overtaking Mac OS, which had been introduced previously. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.The most recent client version of Windows is Windows Vista. The current server version of Windows is Windows Server 2003. The successor to Windows Server 2003, Windows Server 2008, has been released to manufacturing, but is not yet generally available.
MACINTOSH
Macintosh, or for newer models, Mac, is a brand name which covers several lines of personal computers designed, developed, and marketed by Apple Inc. The original Macintosh was released on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a graphical user interface(GUI) rather than a command line interface.
The idea for a personal computer appropriate for the ordinary consumer dates to the late 1970s and an Apple development team was established in 1979. After the success of the original Macintosh in 1984, the company quickly established market share only to see it dissipate in the 1990s as Microsoft came to monopolize personal computing. Apple consolidated multiple, consumer-level desktop models into the 1998 iMac, which sold extremely well and saw the brand name revitalized. Current Mac systems are mainly targeted at the home, education, and creative professional markets. They are the upgraded iMac and the entry-level Mac mini desktop models, the workstation-level Mac Pro tower, the MacBook, MacBook Air and MacBook Pro laptops, and the Xserve server.
LINUX
Linux is one of the most prominent examples of free software and open source development: typically all underlying source code can be freely modified, used, and redistributed by anyone.
Linux is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Linux uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access. Device drivers are integrated directly with the kernel. Linux can be controlled by one or more of a text-based command line interface (CLI), graphical user interface (GUI) (usually the default for desktop), or through controls on the device itself (common on embedded machines).
ref- www.wikipedia.org
Microsoft Windows is the name of several families of software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows eventually came to dominate the world's personal computer market, overtaking Mac OS, which had been introduced previously. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.The most recent client version of Windows is Windows Vista. The current server version of Windows is Windows Server 2003. The successor to Windows Server 2003, Windows Server 2008, has been released to manufacturing, but is not yet generally available.
MACINTOSH
Macintosh, or for newer models, Mac, is a brand name which covers several lines of personal computers designed, developed, and marketed by Apple Inc. The original Macintosh was released on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a graphical user interface(GUI) rather than a command line interface.
The idea for a personal computer appropriate for the ordinary consumer dates to the late 1970s and an Apple development team was established in 1979. After the success of the original Macintosh in 1984, the company quickly established market share only to see it dissipate in the 1990s as Microsoft came to monopolize personal computing. Apple consolidated multiple, consumer-level desktop models into the 1998 iMac, which sold extremely well and saw the brand name revitalized. Current Mac systems are mainly targeted at the home, education, and creative professional markets. They are the upgraded iMac and the entry-level Mac mini desktop models, the workstation-level Mac Pro tower, the MacBook, MacBook Air and MacBook Pro laptops, and the Xserve server.
LINUX
Linux is one of the most prominent examples of free software and open source development: typically all underlying source code can be freely modified, used, and redistributed by anyone.
Linux is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Linux uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access. Device drivers are integrated directly with the kernel. Linux can be controlled by one or more of a text-based command line interface (CLI), graphical user interface (GUI) (usually the default for desktop), or through controls on the device itself (common on embedded machines).
ref- www.wikipedia.org
Comparisons of various e-mail accounts
HOTMAIL
it features 5GB of storage with patented security measures, Ajax technology, and integration with Windows Live Messenger, spaces, calendar and contacts. It has over 280 million users worldwide and is available in 35 different languages.
Features: Like other major webmail services, Hotmail uses Ajax programming techniques and supports the most popular internet browsers (Internet Explorer and Mozilla Firefox). Some of its features include keyboard controls giving the ability to navigate around the page without using the mouse, advanced message search including structured query syntax such as "from:ebay", message filters, folder-based organization of messages, auto-completion of contact addresses when composing, contact grouping, importing and exporting of contacts as CSV files, rich text formatting, rich text signatures, spam filtering and virus scanning, support for multiple addresses, and different language versions. POP3 access, although not directly available through Hotmail, can be accessed via Windows Live Mail, and Microsoft Outlook with Outlook Connector.
Users can choose from two different versions of Hotmail. The "Classic" version keeps the interface and layout based on MSN Hotmail, while still benefitting from the speed of Ajax technology. The "Full" version employs a more advanced user interface styled on that of Microsoft Outlook, with a reading pane and drag-and-drop capability. All other features are available in both versions.
Hotmail also includes other capabilities unlike other e-mail services such as Audio Player, Color Schemes, Integration, Reading Pane, Security and Spell Checker.
GMAIL
Features (storage) : The service currently provides more than 6000 MB of free storage and paid additional storage from 10 GB (US$20/year) up to 400 GB (US$500/year), shared over Picasa and Gmail. The increase from 1 GB was announced on April 1, 2005 and was made for the first anniversary of Gmail. The announcement was accompanied by a statement that Google would "keep giving people more space forever."All Google says about this now is that it will keep increasing storage by the second as long as they have enough space on their servers. On 12 October 2007, Google ramped up the storage counter to 5.37 MB per hour. Approximately a week later, the counter went back down to 1.12 MB per hour. This adds up to about 806 MB per month or over 9.8 GB per year. From 4 January 2008, the counter went down to about 3.35 MB per day.
On August 9, 2007, some users of Gmail reported that their storage capacity had been increased to 9030 MB (8.8 GB). The 9030 MB of space is an over-all total of all the users' storage space(s) within a Google Account, including Picasa. This development seemed to occur about the same time that Google began allowing purchasable Picasa storage. In other words, Google has shared storage space, supporting both pictures and email.
Programming : Gmail makes use of Ajax (specifically, the AjaXSLT framework), employing modern browser features such as JavaScript, keyboard access keys and Web feed integration.
Contacts : Gmail automatically saves contact details when e-mails are sent to an unknown recipient. If the user changes, adds, or removes information near an e-mail such as the name while sending any e-mail, it also updates that in the contact list, unless the user is using basic HTML view, designed for people with slower internet connections or browsers that do not support AJAX. When a user starts typing in the To, CC or BCC fields it brings up a list with the relevant contacts, with their name and primary e-mail address. More information, including alternate email addresses, can be added on the Contacts page. These contacts can also be added to a group, which makes sending multiple e-mails to related contacts easier. Images can be added to contacts, which will appear whenever the mouse is over the contact's name.
Security : Gmail offers a spam filtering system. According to Gmail, messages marked as spam are automatically deleted after 30 days, but there have been reports on Gmail Help Discussion of spam mails staying in the spam folder for months. However, Gmail has now fixed this problem. The spam filtering system cannot be disabled. POP3 users need to check their Spam folder manually via the web interface as only emails sent to the Inbox can be retrieved via POP3.
IP addresses of Gmail users are disguised in order to protect security.
All incoming and outgoing e-mails are automatically scanned for viruses in e-mail attachments. If a virus is found on an attachment the reader is trying to open, Gmail will try to remove the virus and open the cleaned attachment. Gmail also scans all outgoing attachments and will prevent the message from being sent if a virus is found. Executable files are automatically blocked by the Anti-Virus system.
YAHOO
Yahoo Mail is a powerful interface (Full Ajax), very close to a Heavy mail client like Outlook (Drag and drop capabilities, Mail search, tabs...). Yahoo! has integrated Messenger, so the users chat with Yahoo! Messenger and Windows Live Messenger contacts.
Features :
-Unlimited Mail Storage.
-10 MB attachments (20MB for long-time users)
-Protection against spam and viruses.
-Advertising is displayed on the screen while working with the e-mail account.
-POP3 support in some countries (but not in the US). However, SMTP support requires upgrade to a Plus account.
-Accounts not logged into for four months get deactivated (The account can be retrieved but all stored data such as email is lost).
-Early in 2006, Yahoo! Mail introduced aliases to its repertoire of features. Users could now add a (single) alias username containing a dot character for a pre-existing account.
-The Chinese version of Yahoo! Mail offers 3.5 GB quota and 20 MB attachments.
-Some users get features added if they are long time users.
-Users can get around the Web browser access restriction by using software that simulates a POP3 server to which the e-mail application connects. YPOPs! and FreePOPs are examples of free software applications that allow email clients access to webmail services through POP3.
reference- www.wikipedia.org
it features 5GB of storage with patented security measures, Ajax technology, and integration with Windows Live Messenger, spaces, calendar and contacts. It has over 280 million users worldwide and is available in 35 different languages.
Features: Like other major webmail services, Hotmail uses Ajax programming techniques and supports the most popular internet browsers (Internet Explorer and Mozilla Firefox). Some of its features include keyboard controls giving the ability to navigate around the page without using the mouse, advanced message search including structured query syntax such as "from:ebay", message filters, folder-based organization of messages, auto-completion of contact addresses when composing, contact grouping, importing and exporting of contacts as CSV files, rich text formatting, rich text signatures, spam filtering and virus scanning, support for multiple addresses, and different language versions. POP3 access, although not directly available through Hotmail, can be accessed via Windows Live Mail, and Microsoft Outlook with Outlook Connector.
Users can choose from two different versions of Hotmail. The "Classic" version keeps the interface and layout based on MSN Hotmail, while still benefitting from the speed of Ajax technology. The "Full" version employs a more advanced user interface styled on that of Microsoft Outlook, with a reading pane and drag-and-drop capability. All other features are available in both versions.
Hotmail also includes other capabilities unlike other e-mail services such as Audio Player, Color Schemes, Integration, Reading Pane, Security and Spell Checker.
GMAIL
Features (storage) : The service currently provides more than 6000 MB of free storage and paid additional storage from 10 GB (US$20/year) up to 400 GB (US$500/year), shared over Picasa and Gmail. The increase from 1 GB was announced on April 1, 2005 and was made for the first anniversary of Gmail. The announcement was accompanied by a statement that Google would "keep giving people more space forever."All Google says about this now is that it will keep increasing storage by the second as long as they have enough space on their servers. On 12 October 2007, Google ramped up the storage counter to 5.37 MB per hour. Approximately a week later, the counter went back down to 1.12 MB per hour. This adds up to about 806 MB per month or over 9.8 GB per year. From 4 January 2008, the counter went down to about 3.35 MB per day.
On August 9, 2007, some users of Gmail reported that their storage capacity had been increased to 9030 MB (8.8 GB). The 9030 MB of space is an over-all total of all the users' storage space(s) within a Google Account, including Picasa. This development seemed to occur about the same time that Google began allowing purchasable Picasa storage. In other words, Google has shared storage space, supporting both pictures and email.
Programming : Gmail makes use of Ajax (specifically, the AjaXSLT framework), employing modern browser features such as JavaScript, keyboard access keys and Web feed integration.
Contacts : Gmail automatically saves contact details when e-mails are sent to an unknown recipient. If the user changes, adds, or removes information near an e-mail such as the name while sending any e-mail, it also updates that in the contact list, unless the user is using basic HTML view, designed for people with slower internet connections or browsers that do not support AJAX. When a user starts typing in the To, CC or BCC fields it brings up a list with the relevant contacts, with their name and primary e-mail address. More information, including alternate email addresses, can be added on the Contacts page. These contacts can also be added to a group, which makes sending multiple e-mails to related contacts easier. Images can be added to contacts, which will appear whenever the mouse is over the contact's name.
Security : Gmail offers a spam filtering system. According to Gmail, messages marked as spam are automatically deleted after 30 days, but there have been reports on Gmail Help Discussion of spam mails staying in the spam folder for months. However, Gmail has now fixed this problem. The spam filtering system cannot be disabled. POP3 users need to check their Spam folder manually via the web interface as only emails sent to the Inbox can be retrieved via POP3.
IP addresses of Gmail users are disguised in order to protect security.
All incoming and outgoing e-mails are automatically scanned for viruses in e-mail attachments. If a virus is found on an attachment the reader is trying to open, Gmail will try to remove the virus and open the cleaned attachment. Gmail also scans all outgoing attachments and will prevent the message from being sent if a virus is found. Executable files are automatically blocked by the Anti-Virus system.
YAHOO
Yahoo Mail is a powerful interface (Full Ajax), very close to a Heavy mail client like Outlook (Drag and drop capabilities, Mail search, tabs...). Yahoo! has integrated Messenger, so the users chat with Yahoo! Messenger and Windows Live Messenger contacts.
Features :
-Unlimited Mail Storage.
-10 MB attachments (20MB for long-time users)
-Protection against spam and viruses.
-Advertising is displayed on the screen while working with the e-mail account.
-POP3 support in some countries (but not in the US). However, SMTP support requires upgrade to a Plus account.
-Accounts not logged into for four months get deactivated (The account can be retrieved but all stored data such as email is lost).
-Early in 2006, Yahoo! Mail introduced aliases to its repertoire of features. Users could now add a (single) alias username containing a dot character for a pre-existing account.
-The Chinese version of Yahoo! Mail offers 3.5 GB quota and 20 MB attachments.
-Some users get features added if they are long time users.
-Users can get around the Web browser access restriction by using software that simulates a POP3 server to which the e-mail application connects. YPOPs! and FreePOPs are examples of free software applications that allow email clients access to webmail services through POP3.
reference- www.wikipedia.org
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