IT Lectures PDF

Information Technology (IT) Dr. Mostafa Abdo  Why Learn About Computers? Fifty years ago, computers were used primarily by researchers and scientists. Today, computers are an integral part of our lives. Because of the prominence of computers in our society, it is important to und...

Information Technology (IT) Dr. Mostafa Abdo  Why Learn About Computers? Fifty years ago, computers were used primarily by researchers and scientists. Today, computers are an integral part of our lives. Because of the prominence of computers in our society, it is important to understand what a computer is, a little about how a computer works, and the implications of living in a computer- oriented society.  Data vs. Information Any kind of fact or set of facts can become computer data. When data is processed into a meaningful form, it becomes information. Information processing (the conversion of data into information) is a vital activity today for all computer users, as well as for businesses and other organizations.  Characteristics of Computer: Speed: The computer can process data very fast, at the rate of millions of instructions per second. Accuracy: Computer provides a high degree of accuracy. Diligence: When used for a longer period of time, the computer does not get tired or fatigued. Storage Capability: Large volumes of data and information can be stored in the computer and retrieved whenever required. Versatility: Computer is versatile in nature. It can perform different types of tasks with the same ease. Classification of Computer 1. Embedded Computers An Embedded computer is a tiny computer embedded into a product designed to perform specific tasks or functions for that product. For example, computers are often embedded into household appliances to help those appliances and objects perform their designated tasks. 2. Mobile Devices ▪ A mobile device is a very small device that has built-in computing or Internet capability ▪ It can typically be used to make telephone calls, send text messages, view Web pages, take digital photos, play games, download, and play music, watch TV shows, and access calendars and other personal productivity features.  3. Personal Computers (PCs) 3.1 Desktop Computers ▪ Desktop computers can use a tower case , a desktop , or an all-in-one case. ▪ Desktop computer systems usually conform to one of two standards or platforms: PC-compatible or Mac. ▪ PC run the Microsoft Windows operating system. Mac computers are made by Apple and use the Mac OS operating system. ▪ powerful desktop designed for users running powerful applications are sometimes referred to as workstations.  3. Personal Computers (PCs) 3.2. Portable Computers designed to be carried around easily and very flexible designed to be powered by rechargeable batteries a) Notebook computers (laptop) are about the size of a paper. comparable to desktop computers in features and capabilities. b) Tablet computers are typically about the size of a notebook computer and are designed to be used with a digital pen/stylus or touch input c) Hybrid notebook-tablet computers (convertible tablets) can function as either a notebook or a tablet computer. d) Netbooks are like notebook computers but are smaller and have more limited features, such as relying on cloud software.  4. Servers ▪ A Server )minicomputer( is a computer used to host programs and data for a small network ▪ larger, more powerful, and more expensive. ▪ Users connect to the server through a network, using their desktop computer.  5. Mainframe ▪ A mainframe computer is a powerful computer used by many large organizations— such as hospitals, universities, large businesses, banks, and government offices. ▪ Larger, more expensive, and more powerful than servers. ▪ During regular business hours, a mainframe typically runs the programs needed to meet the different needs of its wide variety of users. At night, it commonly performs large processing tasks, such as payroll and billing.  6. Supercomputer ▪ Supercomputers—the most powerful and most expensive type of computer available. ▪ Used for some applications require extraordinary speed, accuracy, and processing capabilities. for example, sending astronauts into space, controlling missile guidance systems and satellites, forecasting the weather, exploring for oil, breaking codes. ▪ Supercomputers generally run one program at a time, as fast as possible. ▪ Example, the Titan supercomputer occupies 4,352 square feet of floor space and contains 299,008 CPUs.  The Computer System 1. Hardware: The physical parts of a computer, can be internal or external. 2. Software: The term software refers to the programs or instructions used to tell the computer hardware what to do. 3. Data: are isolated values or raw facts, provided as input to the computer. 4. Users: are people who write computer programs or interact with the computer. Computer Hardware  Computer Hardware: 1. The Arithmetic/logic unit, which can perform arithmetic and logic operations on data. 2. The Control unit, which serves as the stage manager to ensure that all the other components act in concert. 3. The Memory unit, which holds both data and instructions. 4. The Input unit, which moves data from the outside world into the computer. 5. The Output unit, which moves results from inside the computer to the outside world.  Inside the System Unit ▪ The system unit is the main case of a computer or mobile device. ▪ It houses the processing hardware for that device ▪ The system units for all-in- one computers, notebooks, tablets, and mobile devices are usually combined with the device’s display screen to form a single piece of hardware. The Motherboard ▪ The main circuit board inside the system unit is called the motherboard. ▪ It is a circuit board is a thin board containing computer chips and other electronic components. ▪ All devices used with a computer need to be connected via a wired or wireless connection to the motherboard. ▪ Typically, external devices (such as monitors, keyboards, mice, and printers) connect to the motherboard by plugging into a port.  The Power Supply ▪ The power supply inside a desktop computer connects to the motherboard to deliver electricity to the computer. ▪ Portable computers almost always contain a rechargeable battery pack to power the computer when it is not connected to a power outlet, as well as an external power supply adapter that connects the computer to a power outlet to recharge the battery when needed. ▪ Storage devices inside the system unit are connected via a cable to the motherboard, as well as to the internal power supply if the device requires it.  Processors The primary processor is the central processing unit (CPU)—also called the microprocessor. CPUs are typically designed for a specific type of computer. Most personal computers and servers today use Intel or Advanced Micro Devices (AMD) CPUs; Media tablets and mobile phones often use processors manufactured by other companies (such as ARM) instead.  Processors Another processor located inside the system unit is the graphics processing unit (GPU), which takes care of the processing needed to display images on the screen. In addition to computers and mobile devices, processors are incorporated into a variety of products today, such as TVs, smart meters, cars, gaming consoles, …….. The CPUs for these devices are typically different from the ones used in personal computers and determine the processing capabilities of the device.  Processing Speed One measurement of the processing speed of a CPU is the CPU clock speed, which is typically rated in megahertz (MHz) or gigahertz (GHz). A CPU with a higher CPU clock speed means that more instructions can be processed per second. Today’s fastest CPUs designed for PCs have a clock speed of more than 4 GHz. Benchmark tests are typically run the same series of programs on several computer systems that are identical except for one component (such as the CPU) and measure how long each task takes to determine the overall relative performance of the component being tested.  Word Size A computer word is the amount of data (typically measured in bits or bytes) that a CPU can manipulate at one time. While CPUs just a few years ago used 32-bit words (referred to as 32-bit processors). Most CPUs today are 64-bit processors (that is, they can simultaneously process 64 bits, or 8 bytes, at one time). Usually, a larger word size allows for faster processing. For instance, a computer with a 64-bit processor running the 64-bit version of the Windows operating system can use more RAM and has a higher performance than the same computer running the regular 32-bit version of Windows.  Cache Memory Cache memory is a special group of very fast memory circuitry located on or close to the CPU. Cache memory is used to speed up processing by storing the data and instructions that may be needed next by the CPU in handy locations. Cache memory today is usually internal cache (built right into the CPU chip). If the data or instructions are not found in cache memory, the computer looks for them in RAM, which is slower than cache memory. If the data or instructions cannot be found in RAM, then they are retrieved from the hard drive—an even slower operation. Bus Width, Bus Speed, and Bandwidth A bus is an electronic path over which data can travel. There are buses inside the CPU, as well as on the motherboard. The number of bits being transmitted at one time is dependent on the bus width—the number of wires in the bus over which data can travel. The bus speed is also a very important factor because the bus width and bus speed together determine the bus’s bandwidth—that is, the amount of data that can be transferred via the bus in each time period. 3.3 Memory Memory refers to chip-based storage. Random access memory or RAM is located inside the system unit and used by the computer to store data on a short-term, temporary basis. In contrast, the long-term storage available to a computer—usually in the form of the computer’s internal hard drive or removable storage media (such as CDs, DVDs, flash memory cards, and USB flash drives), but it can also be in the form of chip-based internal storage—especially in mobile devices. In addition to RAM, there are four other types of computer memory. Two of these—cache memory and registers—are volatile like RAM, which means that their content is erased when power to the memory ceases; the other two—read only memory (ROM) and flash memory—are nonvolatile. Random Access Memory (RAM) RAM (random access memory), also called main memory or system memory, is used to store the essential parts of the operating system while the computer is running, as well as the programs and data that the computer is currently using. RAM is volatile, its content is lost when the computer is shut off and when the program using that data is closed. smartphones and mobile devices typically use embedded memory chips RAM capacity is measured in bytes. More RAM allows more applications to run at one time and the computer to respond more quickly CPU must be able to find data and programs located in memory when they are needed. To accomplish this, each location in memory has an address. Random Access Memory (RAM) Registers A register is high-speed memory built into the CPU. Registers are used by the CPU to store data and intermediary results temporarily during processing. Registers are the fastest type of memory used by the CPU, even faster than cache. Generally, more registers and larger registers result in increased CPU performance. Read-Only Memory (ROM) ROM (read-only memory) consists of nonvolatile chips that permanently store data or programs. These chips are attached to the motherboard inside the system unit, and the data or programs are retrieved by the computer when they are needed. You can neither write over the data or programs in ROM chips nor erase their content when you shut off the computer’s power. Traditionally, ROM was used to store the permanent instructions used by a computer (referred to as firmware). However, ROM is increasingly being replaced with flash memory. Read-Only Memory (ROM) ROM consists of nonvolatile memory chips and have begun to replace ROM for storing system information, such as a computer’s BIOS (basic input/output system) or Unified Extensible Firmware Interface UEFI (sequence of instructions the computer follows during the boot process). One of the computer’s first activities when you turn on the power is to perform a power-on self-test or POST. The POST takes an inventory of system components, checks each component to see if it is functioning properly, and initializes system settings, which produces the beeps you may hear as your computer boots. USB Buse USB Bus One of the more versatile bus architectures is the Universal Serial Bus (USB). The USB standard allows 127 different devices to connect to a computer via a single USB port. At 12 Mbps (millions of bits per second), the original USB 1.0 standard is slow. However, the newer USB 2.0 standard supports data transfer rates of 480 Mbps and the newest 4.8 Gbps USB 3.0 standard (also called SuperSpeed USB) is about 10 times as fast as USB 2.0. The convenience and universal support of USB have made it one of the most widely used standards for connecting peripherals