Operating systems: Hidden Software

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The Use of Computers

The digital computer is just a tool. Like a hammer, it comes in various sizes and styles, and it has many uses. As with a hammer, the benefits of using it depend on the skill of the user.

Nowadays the computer is increasingly being used as a component of other machinery, just as hammers are built into pianos, carillons, and hammer mills.

Apart from considerations of manufacture and marketing, machinery with built-in computation, such as a modern sewing machine, is expected to be more capable and easier to use. Usually they are more capable, but all too often they are much harder to use, except when the machine is being used for repetitive work.

A computer, when being used as a computer, is not at all like a hammer in that a hammer is used to manipulate physical objects while a computer is used to manipulate data. Another way the computer is different is that its manipulations are done at two or three levels.

At the hardware level, components such as transistors and capacitors are connected to deal with the individual binary digits of the data.

At the firmware level, functional data called the microprogram is used to control the circuitry of the hardware and to facilitate the software level.

At the software level, operational data called programs are used to cause the computer to manipulate the user’s data in the required way.

That is the nature of computation nowadays, or at least a very simple view of it. Computers have evolved through changes in this structure.

Now the typical computer is an extremely complex structure of hardware, firmware and software, each of which is itself an extremely complex structure. Only specialists deal with the hardware and firmware because programmers and other users of computers are shielded from the complexity of the hardware and firmware by the software.

There are two kinds of software: system programs and application programs.

System programs are of two kinds. The programs of the operating system hide the complexity of the computer from both programmers, particularly those who write the application programs for ordinary users.

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Computers Make the World Smaller and Smarter (part 1)

The ability of tiny computing devices to control complex operations has transformed the way many tasks are performed, ranging from scientific research to producing consumer products. Tiny ‘computers on a chip’ are used in medical equipment, home appliances, cars and toys. Workers use hand held computing devices to collect data at a customer site, to generate forms, to control inventory, and to serve as desktop organisers.

Not only is computing equipment getting smaller, it is getting more sophisticated. Computers are part of many machines and devices that once required continuous human supervision and control. Today, computers in security systems result in safer environments, computers in cars improve energy efficiency, and computers in phones provide features such as call forwarding, call monitoring, and call answering.

These smart machines are designed to take over some of the basic tasks previously performed by people; by so doing, they make life a little easier and a little more pleasant. Smart cards store vital information such as health records, drivers’ licence, bank balances and so on. Smart phones, cars and appliances with built-in computers can be programmed to better meet individual needs. A smart house has a built-in monitoring system that can turn the lights on and off, open and close windows, operate the oven and more.

With small computing devices available for performing smart tasks like cooking dinner, programming the DVD recorder and controlling the flow of information in an organization, people are able to spend more time doing what they often do best – being creative. Computers can help people to work more creatively.

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Computers Make the World Smaller and Smarter (part 2)

Multimedia systems are known for their educational and entertainment value, which we call ‘edutainment’. Multimedia combines text with sound, video, animation, and graphics, which greatly enhances the interaction between user and machine and can make information more interesting and appealing to people. Expert systems software enables computers to ‘think’ like experts. Medical diagnosis expert systems, for example, can help doctors to pinpoint a patient’s illness, suggest further tests, and prescribe appropriate drugs.

Connectivity enables computers and software that might otherwise be incompatible to communicate and to share resources. Now that computers are proliferating in many areas and networks are available for people to access data and communicate with others, personal computers are becoming interpersonal PCs. They have the potential to significantly improve the way we relate to each other. Many people today telecommunicate – that is, use their computers to stay in touch with the office while they are working at home. With the proper tools, hospital staff can get a diagnosis from a medical expert hundreds or thousands of miles away. Similarly, the disabled can communicate more efficiently using computers.

Distance learning and videoconferencing are concepts made possible with the use of an electronic classroom or boardroom accessible to people in remote locations. Vast databases of information are currently available to users of the Internet, all of whom can send mail messages to each other. The information superhighway is designed to significantly expand this interactive connectivity so that people will have free access to all these recourses.

People power is critical to ensuring that hardware, software and connectivity are effectively integrated in a socially responsible way. People – computer users and computer professionals – are the ones who will decide which hardware, software, and networks endure and how great an impact they will have on our lives. Ultimately people power are used not only efficient but in a socially responsible way.

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Computer Hardware in Plain English

If you are like most of the people, computers are becoming a part of your life. They seem complicated inside, but we understand just a few parts. You can see a simple side of computers. This is computer hardware in plain English.

You’ve seen them, they come in all shapes and sizes, and they work pretty much in the same ways. In fact, if you could look inside of these computers, they have the same basic parts. These parts are the following: the hardware that do a lot of the work in computers. To explain let’s look at something you already know – a house. One of the great things about living in a house is that you have room for all of your staff. In fact, many houses have basements and they become the perfect place for storing things that you may want to use later. And the bigger the basement, the more you can store. The same thing is true for computers. Instead of boxes and bicycles, we need a place to store things like photos, music, documents and software. In a computer it’s not the basement but a hard drive. A computer’s hard drive is where you keep all the things you want to use later. And like basements, the bigger the hard drive, the more you can store. But basements are imperfect. Going to the basement takes too much time whenever you need something. Closets on the main floor can help. They are small and make things easier to access when you need them. You don’t need to go all the way downstairs. It’s the same with computers. Some of the information stored on computers is hard for the computer to open quickly because it needs to take the long way. To solve this problem computers use RAM or Random Access Memory. It makes the information easier for the computer to access. This means RAM makes computers faster. Plus, this kind of closet gets cleaned out every time you restart your computer.

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The Internet (A Brief Overview of the History)

The Internet is a global computer network. It started 47 years ago as a military experiment and was originally designed to survive a nuclear war. In 1964 Paul Baran connected 4 computers in different parts of the USA and sent the first message. This was possible due to packet switching. This technology splits information into pieces and they take the shortest path available on the Internet to get from one computer to another. If any computer on the network is knocked out, the information just routes around them.

So, the first computer network was created by Paul Baran and was called APRANET*. The Internet started to develop drastically after 1989. Tim Berners-Lee invented World Wide Web which was an open platform of standards where anyone could create a Web page on the Internet. Since then the number of Web pages has zoomed to nearly 60 billion.

The number of Internet users worldwide is growing and now is more than 2 billion people.

The Internet provides a lot of different services popular nowadays. They are e-mail, social networking, blogging and so on. But some problems still remain. One of them is the problem of security. Information can be intercepted and changed on the Internet. This happens because it is sent without any form of encoding.

*APRANET – Advanced Research Projects Agency Network

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Web 2.0

The Internet is constantly changing and expanding. The next generation of the internet technologies, commonly referred to as Web 2.0, help people connect with others around the world. People can write and comment on blogs and listen to audio files called podcasts. RSS feeds make it easy to subscribe to online content and with an aggregator, so that content can be read, watched, or listened to, at the user’s convenience. In the business world, webinars and webcasts allow companies to use visual media to keep colleagues connected. Customers, competitors, and advisors can all interact using social networking sites. Web 2.0 invites users to be collaborative. We can use our collective expertise to create wikis that serve as online encyclopaedias with constantly updated entries. We can share collections of interesting web links using social bookmarks and tag these links to create folksonomies for easy searching and reference.

Web 2.0 is a term that describes the ‘next generation’ of internet technologies and capabilities. Web 2.0 allows users to interact and collaborate as a community to share and create content in new ways.

A blog is a website that individuals or companies can use to easily post news, opinions, and other information using text, photos, and video.

A webinar is a conference that is broadcast live over the Internet. Participants can ask questions and have live discussions.

Social networking involves communities of users who want to connect with others, who share their interests or background.

A wiki is a website that allows any user to contribute, edit, or change content. It is a way for users to collaborate and share their existing knowledge on a topic.

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Web Creator Berners-Lee:’Sorry For Those Slashes’

David Flynn

16 October 2009, 2:43 AM

Tim Berners-Lee invented the World Wide Web, but says he got it wrong when he put the // in front of the ‘www’. To the estimated 1.67 billion users of the Web, Tim Berners-Lee would like to say “Sorry” for creating the double-slash which precedes the www in each Web page’s address.

Berners-Lee – now officially ‘Sir Tim’ since being knighted in 2004 for creating the World Wide Web (and not making a cent out of it) – admitted at a US technology conference yesterday that the two slashes are unnecessary and were “a mistake”.

“Really, if you think about it, (the Web address) doesn’t need the //. I could have designed it not to have the //”. But, he says, “it seemed like a good idea at the time”. Web browsers have long since side-stepped the double slash, automatically assuming the http:// component when the user enters a Web address.

Prior to the conference, Berners-Lee explained to The New York Times that he automatically chose the // characters when working on what became the Web in the late 1980s, as they were a convention in computer programming at the time.

“When I designed the URL, this thing which starts http://, the slash-slash was to indicate that we are actually starting at the top, not starting down at the next slash” Berners-Lee explains.

The slashes where also to separate the name of the protocol, such as HTTP or FTP, from the rest of the address. However, in the end only the colon was necessary. “With the colon in there as well, it turns out people never use the slash-slash without the http, colon.”

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Graphical User Interface (part 1)

A graphical user interface (GUI) is a type of user interface that allows users to interact with electronic devices using images rather than text commands. A GUI can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and office equipment. A GUI represents the information and actions available to a user through graphical icons and visual indicators as opposed to text-based interfaces. The actions are usually performed through direct manipulation of the graphical elements.

A GUI uses a combination of technologies and devices to provide a platform the user can interact with, for the tasks of gathering and producing information.

This makes it easier for people with few computer skills to work with and use computer software. The most common combination of such elements in GUIs is the WIMP paradigm, which stands for “window, icon, menu and pointing device”.

A window is an area on the screen that displays information. Its contents are displayed independently from the rest of the screen. An example of a window is what appears on the screen when the "My Documents" icon is clicked in the Windows Operating System. It is easy for a user to manipulate a window: it can be opened and closed by clicking on an icon or application, and it can be moved to any area by dragging it. A window can be placed in front or behind another window, its size can be adjusted, and scrollbars can be used to navigate the sections within it. Multiple windows can also be open at one time, in which case each window can display a different application or file – this is very useful when working in a multitasking environment. The system memory is the only limitation to the amount of windows that can be open at once.

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Graphical User Interface (part 2)

Menus allow the user to execute commands by selecting from a list of choices. Options are selected with a mouse or other pointing device within a GUI. A keyboard may also be used. Menus are convenient because they show what commands are available within the software. This limits the amount of documentation the user reads to understand the software.

An icon is a small picture that represents objects such as a file, program, web page, or command. They are a quick way to execute commands, open documents, and run programs. Icons are also very useful when searching for an object in a browser list, because in many operating systems all documents using the same extension will have the same icon.

A cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device.

One of the most common components of a GUI on the personal computer is a pointer: a graphical image on a screen that indicates the location of a pointing device, and can be used to select and move objects or commands on the screen. A pointer commonly appears as an angled arrow, but it can vary within different programs or operating systems. Example of this can be found in web browsers which often indicate that the pointer is over a hyperlink by turning the pointer into the shape of a gloved hand with outstretched index finger.

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PERSONAL COMPUTERS

Personal Computers have become a large part of our lives and have proven to make the society a better place to live. Allowing the PC to do most of the work for us, it cuts our time in half. Programs, written by a technician, enable the PC to think of solutions faster than any human, making the possibilities endless.

A computer is an important thing to people, especially the people who run organizations, industry, etc. Almost anything you know is run or made by computers. Cars and jets were designed on computers, traffic signals are run by computers, most medical equipment use computers and space exploration was started with the help of computers. Most of the jobs today require the use of computers. These 'mechanical brains' made a huge impact on our society. It would be hard if we didn't have the computer around.

Let's visualize for a minute. Let's visualize a world without computers. People in the medical field wouldn't have found a lot of cures to diseases, since most cures were found with the help of computers. Movies like Jurassic Park, Toy Story, A Bug's Life or Godzilla would never have been made without computers because they used computer graphics and animation in them. Counting votes would be impossible without computers and most importantly space exploration wouldn't be possible without the help of computers. It's a pretty tough life without computers. Some may not agree and say, "Well, we don't need computers to live on." They may be right but mostly, they are wrong. Computers help in curing diseases, make entertainment a lot better, keep track of important records, etc. Without computers, all this wouldn't be possible.

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What does a digital camera do?

A digital camera takes photos electronically and converts them into digital data. It doesn't use the film found in a traditional camera; instead it has a special light-sensitive silicon chip. Photographs are stored in the camera's memory card before being sent to the computer. Some cameras can also be connected to a printer or a TV set to make viewing images easier. Digital cameras can do things film cameras cannot: displaying images on a screen immediately after they are recorded, storing thousands of images on a single small memory device, and deleting images to free storage space. The majority, including most compact cameras, can record moving video with sound as well as still photographs. Some can crop and stitch pictures and perform other elementary image editing.

What does a camcorder do?

A camcorder, or a digital video camera, records moving pictures and converts them into digital data that can be stored and edited by a computer with special video editing software. In order to differentiate a camcorder from other devices that are capable of recording video, like mobile phones and digital compact cameras, a camcorder is generally identified as a portable, self-contained device having video capture and recording as its primary function. Digital video cameras are used by home users to create their own movies, or by professionals in art and video conferencing. They are also used to send live video images via the Internet. In this case they are called web cameras, or webcams.

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The nerve centre of a PC is the processor, also called the CPU, or central processing unit. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in use in the computer industry at least since the early 1960s. The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same. The CPU is built into a single chip which executes program instructions and coordinates the activities that take place within the computer system. The chip itself is made of silicon.

Two typical components of a CPU are the arithmetic logic unit, which performs arithmetic and logical operations, and the control unit, which extracts instructions from memory and decodes and executes them, calling on the arithmetic logic unit when necessary.

A processor register is a small amount of storage available as part of a CPU. In fact, they are high-speed units of memory used to store and control data. One of the registers (the program counter) keeps track of the next instruction to be performed in the main memory. The other (the instruction register) holds the instruction that is being executed.

The power and performance of a computer is partly determined by the speed of its processor. A system clock sends out signals at fixed intervals to measure and synchronize the flow of data. Clock speed is measured in gigahertz (GHz). For example, a CPU running at 4GHz (four thousand million hertz, or 30 cycles, per second) will enable your PC to handle the most demanding applications.

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CODEC

A codec is software that is used to compress or decompress a digital media file, such as a song or video. Windows Media Player and other programs use codecs to play and create digital media files.

A codec can consist of two components: an encoder and a decoder. The encoder performs the compression (encoding) function and the decoder performs the decompression (decoding) function. Some codecs include both of these components and some codecs only include one of them.

For example, when you rip a song from an audio CD to your computer, the Player uses Window Media Audio codec by default to compress the song into a compact WMA file. When you play the WMA file (or any WMA file that might be streamed from a website), the Player uses the Windows Media Audio codec to decompress the file so the music can be played through your speakers.

There are hundreds of audio and video codecs in use today. Some have been created by Microsoft, but the vast majority of codecs have been created by other companies, organizations, or individuals. By default, the Windows operating system and the Player include a number of the most popular codecs, such as Windows Media Audio, Windows Media Video, and MP3.

There might be times, however, when you want to play content that was compressed with a codec that Windows or the Player doesn’t include by default. In many cases, you can download the necessary codec from the web for free or for a fee. And, in some cases, the Player can automatically use the codecs installed by other digital playback and creation programs on your computer.

If you know the name of the codec or its ID (known as a FourCC identifier for video codecs or a WaveFormat identifier for audio codecs), try searching the Internet. You can often go to a codec manufacturer’s website to download the most recent version of a codec.

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How To Use Bold Type Effectively

A typeface with thicker strokes than regular is called bold type. It is heavier, darker than regular type. Many type families include bold versions of the basic typeface. They may also have Heavy or Ultra Bold weights and Bold Italic.

One way to grab attention in a sea of words is to set some text in bold founts. It is heavier, darker than regular type. Bold founts are used for emphasis to make certain words and phrases stand out from surrounding text. Here are some useful tips.

You can use bold founts to emphasize something, to highlight important points. But be careful and use restraint when using bold type. Whole paragraphs of text set in bold type are hard to read. The reason bold type creates emphasis is that it slows down the reader and forces their eye to really take in the words more carefully. But if you slow them down too much they may just skip over what you have to say.

One can also create contrast by using bold fonts. Use bold fonts for headlines to increase the contrast between headlines and body text.

Use bold fonts to aid skimming of instructional text. In some instances it is useful to readers to have titles, proper names, or key terms in a manual within a block of copy highlighted with bold for ease in scanning.

Avoid fake bold fonts. Set type in the bold (or heavy) version of a typeface rather than using the bold style function of your software. If a true bold version of a font is not installed the software creates a weaker fake bold. If the bold version of a font doesn't appear in your font list after it is installed (common in Windows), then go ahead and use the bold style option – the software should find and use the bold version.

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Computer Applications (Speed Traps)

In the last ten years, police have installed speed trap units on many busy roads. These contain a radar set, a microprocessor and a camera equipped with a flash. The radar sends out a beam of radio waves at a frequency of 24 gigahertz. This is equivalent to a wavelength of 1.25 cms. If a car is moving towards the radar, the reflected signal will bounce back with a slightly smaller wavelength. If away from the radar, the waves will reflect with a slightly longer wavelength. The microprocessor within the unit measures the difference in wavelength between outgoing and returning signals and calculates the speed of each vehicle. If it is above the speed pre-set by the police, the camera takes a picture of the vehicle. The information is stored on a smart card for transfer to the police computer. The owner of the vehicle can then be traced using the Driver and Vehicle Licensing Centre database.

Some drivers have now got used to these traps. They slow down when they approach one to ensure that the camera is not triggered. They speed up again as soon as they have passed. This is known as ‘surfing’. One way of outwitting such motorists is a new computerized system. This consists of two units equipped with digital cameras positioned at a measured distance apart. The first unit records the time each vehicle passes it and identifies each vehicle by its number plates, using optical character recognition software. This information is relayed to the second unit which repeats the exercise. The microprocessor within the second unit then calculates the time taken by each vehicle to travel between the units. The registration numbers of these vehicles exceeding the speed limit are relayed to police headquarters where a computer matches each vehicle with the DVLC database. Using mailmerge a standard letter is then printed off addressed to the vehicle owner.

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How Do I Remove a Computer Virus?

Keep your antivirus program up-to-date. If you have already installed an antivirus program on your computer, it’s important that you keep it up-to-date. Because new viruses are being written all the time, most antivirus programs are updated frequently. Check your antivirus program’s documentation or visit their website to learn how to receive updates.

Stop a runaway virus. Viruses are sometimes created specifically to take control of your computer and send copies of themselves from your computer to other computers. You can usually tell this is happening if your computer is performing slowly and accessing the network more frequently than normal. If this happens, you should disconnect from the Internet and network (if you’re on one); run your antivirus software (from a disc or a software on your computer) to remove the virus.

Manually remove viruses. Sometimes a virus must be removed manually. This is often a technical process and should only be attempted by computer users who have experience with the Windows registry and who know how to view and delete system and program files in Windows.

The first step to identify the virus. Run your antivirus software to identify the name of the virus. If you don’t have an antivirus program, or if your program does not delete the virus, you can still identify the virus by looking for clues about how it behaves. Write down the text in any messages displayed by the virus or, if you received a virus in e-mail, write down the subject line or name of the file attached to the message. Search the antivirus vendor’s website for references to those specific things you wrote down to find the name of the virus and instructions how to remove it.

My virus is gone. Now what? Once a virus is removed, you might have to reinstall some software, or restore lost information. Doing regular backups can go a long way toward easing the pain of a virus attack. If you haven’t kept backups, start now.

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How Information Travels Over the Internet

All information is transmitted across the Internet in small units of data called packets for transmission; software on the receiving computer regroups incoming packets into the original document. Similar to a postcard, each packet has two parts: a packet header specifying the computer to which the packet should be delivered, and a packet payload containing the data being sent. The header also specifies how the data in the packet should be combined with the data in other packets be recording which piece of document is contained in the packet.

A series of rules known as computer communication protocols specify how packet headers are formed and how packets are processed. The set of protocols used for the Internet are named TCP/IP after the two most important protocols in the set: the Transmission Control Protocol and the Internet Protocol. Hardware devices that connect networks in the Internet are called IP routers because they follow the IP protocol when forwarding packets. A router examines the header in each packet that arrives to determine the packet’s destination. The router either delivers the packet to the destination computer across a local network or forwards the packet to another router that is closer to the final destination. Thus, a packet travels from router to router as it passes through the Internet.

TCP/IP protocols enable the Internet to automatically detect and correct transmission problems. For example, if any network or device malfunctions, protocols detect the failure and automatically find an alternative path for packets to avoid malfunctions. Protocol software also ensures that data arrives complete and intact. If any packets are missing or damaged, protocol software on the receiving computer requests that the source resends them. Only when the data has arrived correctly, does the protocol software make it available to the receiving application program, and therefore to the user.

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Operating systems: Hidden Software

When a brand new computer comes off the factory assembly line, it can do nothing. The hardware needs software to make it work. Are we talking about applications software such as wordprocessing or spreadsheet software? Partly. But an applications software package does not communicate directly with the hardware. Between the applications software and the hardware is a software interface – an operating system. An operating system is a set of programs that lies between applications software and the computer.

The most important program in the operating system, the program that manages the operating system, is the supervisor program, most of which remains in memory and is thus referred to as resident. The supervisor controls the entire operating system and loads into memory other operating system programs (called non-resident) from disk storage only as needed.

An operating system has three main functions: (1) manage the computer’s resources, such as the central processing unit, memory disk drives, and printers, (2) establish a user interface, and (3) execute and provide services for applications software. Keep in mind, however, that much of the work of an operating system is hidden from the user. In particular, the first listed function, managing the computer’s resources, is taken care of without the user being aware of the details.

Furthermore, all input and output operations, although invoked by an applications program, are actually carried out by the operating system.

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