Computer and Softwares Tips

Computer software, or just software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system.The term includes application software such as word processors which perform productive tasks for users, system software such as operating systems, which interface with hardware to provide the necessary services for application software, and middleware which controls and co-ordinates distributed systems.

"Software" is sometimes used in a broader context to mean anything which is not hardware but which is used with hardware, such as film, tapes and records.

Relationship to computer hardware

Computer software is so called to distinguish it from computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. At the lowest level, software consists of a machine language specific to an individual processor. A machine language consists of groups of binary values signifying processor instructions which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer hardware in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code. Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler.

There Are Three Types of Softwares:

System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, windowing systems, utilities and more. The purpose of systems software is to insulate the applications programmer as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such as accessory devices as communications, printers, readers, displays, keyboards, etc.

Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way. The tools include text editors, compilers, interpreters, linkers, debuggers, and so on. An Integrated development environment (IDE) merges those tools into a software bundle, and a programmer may not need to type multiple commands for compiling, interpreting, debugging, tracing, and etc., because the IDE usually has an advanced graphical user interface, or GUI.

Application software allows end users to accomplish one or more specific (non-computer related) tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. Businesses are probably the biggest users of application software, but almost every field of human activity now uses some form of application software

Users often see things differently than programmers. People who use modern general purpose computers (as opposed to embedded systems, analog computers, supercomputers, etc.) usually see three layers of software performing a variety of tasks: platform, application, and user software.

Platform software

Platform includes the firmware, device drivers, an operating system, and typically a graphical user interface which, in total, allow a user to interact with the computer and its peripherals (associated equipment). Platform software often comes bundled with the computer. On a PC you will usually have the ability to change the platform software.

Application software

Application software or Applications are what most people think of when they think of software. Typical examples include office games. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are almost always independent programs from the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other "system software" as applications.

User-written software

End-user development tailors systems to meet users' specific needs. User software include spreadsheet templates, word processor macros, scientific simulations, and scripts for graphics and animations. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is. Depending on how competently the user-written software has been integrated into purchased application packages, many users may not be aware of the distinction between the purchased packages, and what has been added by fellow co-workers.

Software reliability considers the errors, faults, and failures related to the design, implementation and operation of software.

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A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The term "virus" is also commonly used, albeit erroneously, to refer to many different types of malware and adware programs. The original virus may modify the copies, or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as a floppy disk, CD, or USB drive. Meanwhile viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm can spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a file that appears harmless. Worms and Trojans may cause harm to either a computer system's hosted data, functional performance, or networking throughput, when executed. In general, a worm does not actually harm either the system's hardware or software, while at least in theory, a Trojan's payload may be capable of almost any type of harm if executed. Some can't be seen when the program is not running, but as soon as the infected code is run, the Trojan horse kicks in. That is why it is so hard for people to find viruses and other malware themselves and why they have to use spyware programs and registry processors.

Most personal computers are now connected to the Internet and to local area networks, facilitating the spread of malicious code. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, Instant Messaging and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

Some malware is programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Other malware programs are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these less sinister malware programs can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, much malware is bug-ridden, and these bugs may lead to system crashes and data loss. Many CiD programs are programs that have been downloaded by the user and pop up every so often. This results in slowing down of the computer, but it is also very difficult to find and stop the problem.

Resident viruses contain a replication module that is similar to the one that is employed by nonresident viruses. However, this module is not called by a finder module. Instead, the virus loads the replication module into memory when it is executed and ensures that this module is executed each time the operating system is called to perform a certain operation. For example, the replication module can be called each time the operating system executes a file. In this case, the virus infects every suitable program that is executed on the computer.

Vectors and hosts

Viruses have targeted various types of transmission media or hosts. This list is not exhaustive:

> Binary executable files (such as COM files and EXE files in MS-DOS, Portable Executable files in Microsoft Windows, and ELF files in Linux)
> Volume Boot Records of floppy disks and hard disk partitions
> The master boot record (MBR) of a hard disk
> General-purpose script files (such as batch files in MS-DOS and Microsoft Windows, VBScript files, and shell script files on Unix-like platforms).
> Application-specific script files (such as Telix-scripts)
> Documents that can contain macros (such as Microsoft Word documents, Microsoft Excel spreadsheets, AmiPro documents, and Microsoft Access database files)
> Cross-site scripting vulnerabilities in web applications
> Arbitrary computer files. An exploitable buffer overflow, format string, race condition or other exploitable bug in a program which reads the file could be used to trigger the execution of code hidden within it. Most bugs of this type can be made more difficult to exploit in computer architectures with protection features such as an execute disable bit and/or address space layout randomization.PDFs, like HTML, may link to malicious code.

It is worth noting that some virus authors have written an .EXE extension on the end of .PNG (for example), hoping that users would stop at the trusted file type without noticing that the computer would start with the final type of file. (Many operating systems hide the extensions of known file types by default, so for example a filename ending in ".png.exe" would be shown ending in ".png".) See Trojan horse (computing).

Some viruses can infect files without increasing their sizes or damaging the files. They accomplish this by overwriting unused areas of executable files. These are called cavity viruses.

Stealth

Some viruses try to trick anti-virus software by intercepting its requests to the operating system. A virus can hide itself by intercepting the anti-virus software’s request to read the file and passing the request to the virus, instead of the OS. The virus can then return an uninfected version of the file to the anti-virus software, so that it seems that the file is "clean". Modern anti-virus software employs various techniques to counter stealth mechanisms of viruses. The only completely reliable method to avoid stealth is to boot from a medium that is known to be clean.

Self-modification

Most modern antivirus programs try to find virus-patterns inside ordinary programs by scanning them for so-called virus signatures. A signature is a characteristic byte-pattern that is part of a certain virus or family of viruses. If a virus scanner finds such a pattern in a file, it notifies the user that the file is infected. The user can then delete, or (in some cases) "clean" or "heal" the infected file. Some viruses employ techniques that make detection by means of signatures difficult but probably not impossible. These viruses modify their code on each infection. That is, each infected file contains a different variant of the virus.

The vulnerability of operating systems to viruses

The diversity of software systems on a network similarly limits the destructive potential of viruses.

Anti-virus software and other preventive measures

Many users install anti-virus software that can detect and eliminate known viruses after the computer downloads or runs the executable. There are two common methods that an anti-virus software application uses to detect viruses. The first, and by far the most common method of virus detection is using a list of virus signature definitions. This works by examining the content of the computer's memory (its RAM, and boot sectors) and the files stored on fixed or removable drives (hard drives, floppy drives), and comparing those files against a database of known virus "signatures". The disadvantage of this detection method is that users are only protected from viruses that pre-date their last virus definition update. The second method is to use a heuristic algorithm to find viruses based on common behaviors. This method has the ability to detect viruses that anti-virus security firms have yet to create a signature for.

Some anti-virus programs are able to scan opened files in addition to sent and received e-mails 'on the fly' in a similar manner. This practice is known as "on-access scanning." Anti-virus software does not change the underlying capability of host software to transmit viruses. Users must update their software regularly to patch security holes. Anti-virus software also needs to be regularly updated in order to prevent the latest threats.

One may also minimise the damage done by viruses by making regular backups of data (and the Operating Systems) on different media, that are either kept unconnected to the system (most of the time), read-only or not accessible for other reasons, such as using different file systems. This way, if data is lost through a virus, one can start again using the backup (which should preferably be recent). If a backup session on optical media like CD and DVD is closed, it becomes read-only and can no longer be affected by a virus. Likewise, an Operating System on a bootable can be used to start the computer if the installed Operating Systems become unusable. Another method is to use different Operating Systems on different file systems. A virus is not likely to affect both. Data backups can also be put on different file systems. For example, Linux requires specific software to write to NTFS partitions, so if one does not install such software and uses a separate installation of MS Windows to make the backups on an NTFS partition, the backup should remain safe from any Linux viruses. Likewise, MS Windows can not read file systems like ext3, so if one normally uses MS Windows, the backups can be made on an ext3 partition using a Linux installation.

Virus removal

One possibility on Windows Me, Windows XP and Windows Vista is a tool known as System Restore, which restores the registry and critical system files to a previous checkpoint. Often a virus will cause a system to hang, and a subsequent hard reboot will render a system restore point from the same day corrupt. Restore points from previous days should work provided the virus is not designed to corrupt the restore files. Some viruses, however, disable system restore and other important tools such as Task Manager and Command Prompt. An example of a virus that does this is CiaDoor.

Administrators have the option to disable such tools from limited users for various reasons. The virus modifies the registry to do the same, except, when the Administrator is controlling the computer, it blocks all users from accessing the tools. When an infected tool activates it gives the message "Task Manager has been disabled by your administrator.", even if the user trying to open the program is the administrator.

Users running a Microsoft operating system can go to Microsoft's website to run a free scan, if they have their 20-digit registration number.

Computer and Video Games (CVG) is a video game magazine in the United Kingdom. Initially published monthly between November 1981 and October 2004 and solely web-based from 2004 onwards[1], the magazine was one of the first publications to capitalise on the growing home computing market, although it also covered arcade games. The magazine saw many changes over the course of its life, and by the mid 1990's had switched focus to concentrate entirely on games consoles.

The magazine was "suspended" in 2004 after Future Publishing bought the magazine (alongside PC Zone) from Dennis Publishing Ltd who had themselves purchased it from the magazine's original publishers EMAP. Future, who also published CVG's main rival, GamesMaster, subsequently decided to publish their magazine as opposed to keeping CVG in operation. Subscribers received a copy of GamesMaster in place of CVG, along with a letter claiming the magazine had been suspended to allow the staff a break and would return in a few months.

The magazine returned in a new form, titled CVG Presents, on 16 April 2008 with a bi-monthly release schedule.The new format concentrates the whole magazine on a single subject. The first issue of the new format concentrated on the history of the Grand Theft Auto series of games.

In the meantime, the magazine's website has continued to flourish, and recently Future incorporated the forums of many of its other games related publications to ComputerAndVideoGames.com in addition to devoting sections to those that did not previously have a formal website, such as PC Gamer.

This tip is very useful for home users, particularly for those who wants to hide/secure there important data from other users. You can hide any specific local drive or all drives (physical and removable) of the system and network drives also. By disabling the display of drives, you can safe your personal data from non-technical users on a single computer.

Follow the given steps to change the system drives registry value:

To use this feature, you will need to be logged into your computer with administrative rights.

Click Start button and type regedit in Run option then press Enter for next.



Here locate the location to:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion \Policies\Explorer



Here in right side panel, right click to create a new DWORD value with name

NoDrives (it is case sensitive), then assign number to its value data box.



Now if you want to hide all system drives then modify value data to 3FFFFFF.




For specific drive use values (For example, for A, B, C, D, E, F, G, H drives,

the values are 1, 2, 4, 8, 16, 32, 64, and 128 respectively).

In this case we are trying to hide F drive, so we modify the value data box to 32.



Now close the registry editor and restart your computer after any changes to go into effect.
But next time, if you want to unhide this drive then simply change the value data box or delete the DWORD item.
Again close the registry editor and restart your computer after any changes to go into effect.

If your CD drive creating problem to read CD disc, taking time to read and showing message there is no disc in the drive. These are the symptoms of dirty or weak CD-drive lens, because dirty lens can create errors in reading or writing and soon will not work at all.

Follow the given steps to care and clean a CD-Drive.

> First make sure your discs are clean, unscratched and you are loaded it properly.

> Always use laser lens cleaner to clean drive lens.

> Insert the laser lens cleaner disc and play it for 2 to 3 min.

Using CD drive cleaner properly clean the CD-ROM laser from dust.If your drive still creating problem then open it and clean the lens with a cotton swab.

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Related : Cd/Dvd Cleaner
Related : CD/DVD Cleaning Tips

While your computing is booting, you can instruct the computer to boot in 'safe mode'. Safe mode refers to secure mode. You may then ask, is our computer not secure when we boot normally. Let us see how is safe mode more secure than the normal booting.

When your computer gives problems and you want to identify where is the problem, then you can use the safe mode for this. In safe mode, only limited number of driver programs are enabled. Therefore you cannot use CD drive. You cannot use the printer. And many other unnecessary drivers are not enabled.

While in Safe Mode, you can use the ScanDisk, defrag and other utility programs to repair your computer. To bring the computer to safe mode. When Computer Turns on, you have to press the F8 key. You should press the F8 key before the windows screen appears. Then you can choose the safe mode option to boot.

Some Anti virus software will tell you that some viruses can only be removed in safe mode, therefore the antivirus software will automatically start in safe mode or you may have to goto safe mode and then run the virus removal utility to remove the virus.

Related: Pc's Safe Mode
Related: Remove Virus Safely in Safe Mode

“SHUTCMD.EXE” utility that you can use to shutdown or restart your local or remote computer. You must first logon to the computer that you're trying to reboot.

You can shutdown the local computer by running this command:


SHUTCMD /L

To shutdown a computer on your network ("SERVER" the name of the computer you want to shutdown):

SHUTCMD \\SERVER /Y

To shutdown a remote computer connected to the Internet ("131.200.1.1" being the IP address of that computer you want to shutdown).

SHUTCMD \\131.200.1.1 /Y

For Example,
To shut down the local computer in two minutes and display a "The computer is shutting down" message, use the following line in a batch file or type it at a command prompt, and then press ENTER:
shutdown /l /t:120 "The computer is shutting down" /y /c
To cancel the shutdown process, type the following line at the command prompt, and then press ENTER:
shutdown /l /a /y
• To shut down and restart a remote computer named "Support," use the following line in a batch file or type it at a command prompt, and then press ENTER:
shutdown \\support /r
• To schedule the local computer to shutdown and restart at 10:00 P.M., type the following line at a command prompt, and then press ENTER:
at 22:00 shutdown /l /r /y /c
• To schedule the local computer to shutdown and restart at 6:00 P.M. every weekday, type the following line at a command prompt, and then press ENTER:
at 18:00 /every:M,T,W,Th,F shutdown /l /r /y /c

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We are all familiar with what a computer is in a specific, contemporary sense. Personal computers are found in most aspects of daily life, and for some it is hard to even imagine a world without them. But the term computer means more than simply the Macs and PCs we are familiar with. A computer is, at its most basic, a machine which can take instructions, and perform computations based on those instructions.

It is the ability to take instructions — often known as programs in the parlance of computers — and execute them, that distinguishes a computer from a mechanical calculator. While both are able to make computations, a calculator
responds simply to immediate input. In fact, most modern calculators are actually computers, with a number of pre-installed programs to help aid in complex tasks.

Computers range from the very small to the very large. Some are capable of doing millions of calculations in a single second, while others may take long periods of time to do even the most simple calculations. But theoretically, anything one computer is capable of doing, another computer will also be able to do. Given the right instructions, and sufficient memory, a computer found in a wristwatch should be able to accomplish anything a supercomputer can — although it might take thousands of years for the wristwatch to complete the operation.

At one time, computers were extremely large, and required enormous amounts of power. This made them useful only for a small amount of tasks — computing trajectories for astronomical or military applications, for example, or code breaking. Over time, with technological advances, the computer was scaled down and its energy equirements lowered immensely. This allowed the power of the computer to be harnessed for a taggering array of uses.

Computers are not very intelligent devices, but they handle instructions flawlessly and fast. They must follow explicit directions from both the user and computer programmer. Computers are really nothing more than a very powerful calculator with some great accessories. Applications like word processing and games are just a very complex math problem.

Operating system software provides a "user interface" for users to manage files, start programs, customize computer settings, and other tasks. The operating system also provides the fundamental core computer functionality for programmers.

Computers can be generally classified by size and power as follows, though there is considerable overlap:

Personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.Personal computers first appeared in the late 1970s. One of the first and most popular personal computers was the Apple II, introduced in 1977 by Apple Computer. During the late 1970s and early 1980s, new models and competing operating systems seemed to appear daily. Then, in 1981, IBM entered the fray with its first personal computer, known as the IBM PC. The IBM PC quickly became the personal computer of choice, and most other personal computer manufacturers fell by the wayside. One of the few companies to survive IBM's onslaught was Apple Computer, which remains a major player in the personal computer marketplace.

Other companies adjusted to IBM's dominance by building IBM clones, computers that were internally almost the same as the IBM PC, but that cost less. Because IBM clones used the same microprocessors as IBM PCs, they were capable of running the same software. Over the years, IBM has lost much of its influence in directing the evolution of PCs. Many of its innovations, such as the MCA expansion bus and the OS/2 operating system, have not been accepted by the industry or the marketplace.

Today, the world of personal computers is basically divided between Apple Macintoshes and PCs. The principal characteristics of personal computers are that they are single-user systems and are based on microprocessors. However, although personal computers are designed as single-user systems, it is common to link them together to form a network. In terms of power, there is great variety. At the high end, the distinction between personal computers and workstations has faded. High-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and DEC.

Workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.Workstations generally come with a large, high-resolution graphics screen, at least 64 MB (megabytes) of RAM, built-in network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. The most common operating systems for workstations are UNIX and Windows NT.


Minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.A midsized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously.

Mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.

Supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.The fastest type of computer. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration.

The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.

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