K13-03-04 DIGITAL TEHNIQUES / ELECTRONICS INTRUMENT SYSTEM .NAMA :NDP :LE 2 : RECOGNIZE THE BASIC COMPUTER STRUCTURE

MOTHERBOARDThe motherboard is a sheet of plastic that holds all the circuitry to connect the various components of a computer system. Learn how the motherboard functions to make all the other components work together.DefinitionA motherboard is one of the most essential parts of a computer system. It holds together many of the crucial components of a computer, including the central processing unit (CPU), memory and connectors for input and output devices. The base of a motherboard consists of a very firm sheet of non-conductive material, typically some sort of rigid plastic. Thin layers of copper or aluminum foil, referred to astraces, are printed onto this sheet. These traces are very narrow and form the circuits between the various components. In addition to circuits, a motherboard contains a number of sockets and slots to connect the other components.Parts of a Motherboard A CPU socket - the actual CPU is directly soldered onto this socket. Since high speed CPUs generate a lot of heat, there are heat sinks and mounting points for fans right next to the CPU socket. A power connector to distribute power to the CPU and other components. Slots for the system's main memory, typically in the form of DRAM chips. A chip forms an interface between the CPU, the main memory and other components. On many types of motherboards this is referred to as the Northbridge. This chip also contains a large heat sink. A second chip controls the input and output (I/O) functions. It is not connected directly to the CPU but to the Northbridge. This I/O controller is referred to as the Southbridge. The Northbridge and Southbridge combined are referred to as thechipset. Several connectors, which provide the physical interface between input and output devices and the motherboard. The Southbridge handles these connections. Slots for one or more hard drives to store files. The most common types of connections are Integrated Drive Electronics (IDE) and Serial Advanced Technology Attachment (SATA). A Read-only memory (ROM) chip, which contains the firmware, or startup instructions for the computer system. This is also called the BIOS. A slot for a video or graphics card. There are a number of different types of slots, including Accelerated Graphics Port (AGP) and Peripheral Component Interconnect Express (PCIe). Additional slots to connect hardware in the form of Peripheral Component Interconnect (PCI) slots.

PROCESSORThe central processing unit (CPU) is the brain of your computer. It handles all the instructions you give your computer, and the faster it does this, the better. Learn about how a CPU processes instructions and how computer engineers are continuously coming up with ways to make it go faster.DefinitionsThecentral processing unit (CPU)of a computer is a piece of hardware that carries out the instructions of a computer program. It performs the basic arithmetical, logical, and input/output operations of a computer system. The CPU is like the brains of the computer - every instruction, no matter how simple, has to go through the CPU. So let's say you press the letter 'k' on your keyboard and it appears on the screen - the CPU of your computer is what makes this possible. The CPU is sometimes also referred to as the central processor unit, or processor for short. So when you are looking at the specifications of a computer at your local electronics store, it typically refers to the CPU as theprocessor.ComponentsA typical CPU has a number ofcomponents. The first is the arithmetic logic unit (ALU), which performs simple arithmetic and logical operations. Second is the control unit (CU), which manages the various components of the computer. It reads and interprets instructions from memory and transforms them into a series of signals to activate other parts of the computer. The control unit calls upon the arithmetic logic unit to perform the necessary calculations.Third is the cache, which serves as high-speed memory where instructions can be copied to and retrieved. Early CPUs consisted of many separate components, but since the 1970s, they have been constructed as a single integrated unit called amicroprocessor. As such, a CPU is a specific type of microprocessor. The individual components of a CPU have become so integrated that you can't even recognize them from the outside. This CPU is about two inches by two inches in size.CPUs are located on themotherboard. Motherboards have a socket for this, which is specific for a certain type of processor. A CPU gets very hot and therefore needs its own cooling system in the form of a heat sink and/or fan.The ALU is where the calculations occur, but how do these calculations actually get carried out? To a computer, the world consists of zeros and ones. Inside a processor, we can store zeros and ones using transistors. These are microscopic switches that control the flow of electricity depending on whether the switch is on or off. So the transistor contains binary information: a one if a current passes through and a zero if a current does not pass through.Transistors are located on a very thin slice of silicon. A single silicon chip can contain thousands oftransistors. A single CPU contains a large number of chips. Combined, these only cover about a square inch or so. In a modern CPU, however, that square inch can hold several hundred million transistors - the very latest high-end CPUs have over one billion! Calculations are performed by signals turning on or off different combinations of transistors. And more transistors means more calculations. You may be interested to know that the material silicon used in chips is what gave the Silicon Valley region of California its name.

HARD DRIVE Thehard driveof a computer is a device that stores all the software installed on a computer, as well as all the data files created and used by this software. This includes any documents you have created and downloaded, such as photos and music. The hard drive is a form of permanent storage, rather than temporary memory such as random-access memory (RAM). This means that when you turn off the computer the files remain safely stored on the drive so you can use them again the next time you start your computer.There are two general types of hard drives:hard disk drives (HDD), which use one or more rotating discs and rely on magnetic storage, andsolid-state drives (SDD), which have no moving mechanical parts, but use flash memory like the kind found in USB flash drives. If you have a regular desktop computer, you most likely have a hard disk drive. Solid-state drives are more typical for high-end, expensive laptops.

CD ROMCD-ROM (Compact Disc, read-only-memory) is an adaptation of the CD that is designed to store computer data in the form of text and graphics, as well as hi-fi stereo sound. The original data format standard was defined by Philips and Sony in the 1983 Yellow Book. Other standards are used in conjunction with it to define directory and file structures, including ISO 1660, HFS (Hierarchal File System, for Macintosh computers), and Hybrid HFS-ISO. Format of the CD-ROM is the same as for audio CDs: a standard CD is 120 mm (4.75 inches) in diameter and 1.2 mm (0.05 inches) thick and is composed of a polycarbonate plastic substrate (underlayer - this is the main body of the disc), one or more thin reflective metal (usually aluminum) layers, and a lacquer coating.The Yellow Book specifications were so general that there was some fear in the industry that multiple incompatible and proprietary formats would be created. In order to prevent such an occurrence, representatives from industry leaders met at the High Sierra Hotel in Lake Tahoe to collaborate on a common standard. Nicknamed theHigh Sierra Format, this version was later modified to become ISO 9660. Today, CD-ROMs are standardized and will work in any standard CD-ROM drive. CD-ROM drives can also read audio compact discs for music, although CD players cannot read CD-ROM discs.

RAM

Random-access memory (RAM)is a type of computer data storage. A RAM device makes it possible to access data in random order, which makes it very fast to find a specific piece of information. Certain other types of storage are not random-access. For example, a hard disk drive and a CD will read and write data in a predetermined order. The mechanical design of these devices prescribes that data access is consecutive. This means that the time it takes to find a specific piece of information can vary greatly depending on where it is located on the disk.RAM devices are used in computer systems as the main memory. RAM is consideredvolatile memory, which means that the stored information is lost when there is no power. So, RAM is used by the central processing unit (CPU) when a computer is running to store information that needs to be used very quickly, but it does not store any information permanently.Present-day RAM devices use integrated circuits to store information. This is a relatively expensive form of storage and the cost per unit of storage is much higher than for devices like a hard drive. However, the time to access data is so much faster for RAM that speed outweighs cost. A computer therefore uses a certain amount of RAM for fast-access, temporary storage of information and a much larger amount of non-random, permanent mass storage, like a hard disk drive. For example, a typical computer system may have two to eight GB (gigabytes) of RAM, while the storage capacity of the hard disk drive can be several hundred GB or even one TB (terabyte).

POWER SUPPLY

Apower supplyis an electronic device that supplieselectric energyto anelectrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to aselectric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads. Examples of the latter include power supplies found indesktop computersandconsumer electronicsdevices.Every power supply must obtain the energy it supplies to its load, as well as any energy it consumes while performing that task, from an energy source. Depending on its design, a power supply may obtain energy from various types of energy sources, including electrical energy transmission systems,energy storagedevices such as abatteriesandfuel cells, electromechanical systems such asgeneratorsandalternators,solar powerconverters, or another power supply.All power supplies have apower input, which receives energy from the energy source, and apower outputthat delivers energy to the load. In most power supplies the power input and output consist ofelectrical connectorsor hardwired circuit connections, though some power supplies employwireless energy transferin lieu of galvanic connections for the power input or output. Some power supplies have other types of inputs and outputs as well, for functions such as external monitoring and control.

FLOPPY A-DRIVE

Afloppy diskis a magnetic storage medium for computer systems. The floppy disk is composed of a thin, flexible magnetic disk sealed in a square plastic carrier. In order to read and write data from a floppy disk, a computer system must have a floppy disk drive (FDD). A floppy disk is also referred to simply as a floppy. Since the early days of personal computing, floppy disks were widely used to distribute software, transfer files, and create back-up copies of data. When hard drives were still very expensive, floppy disks were also used to store the operating system of a computer.A number of different types of floppy disks have been developed, the size of the floppy got smaller, and the storage capacity increased; however, in the 1990s, other media, including hard disk drives, ZIP drives, optical drives, and USB flash drives, started to replace floppy disks as the primary storage medium.Types of Floppy DisksThe first floppy disks that came on the market were 8 inches (200 mm) in diameter. The disk was protected by a flexible plastic jacket. An 8-inch disk back in the late 1970s could store about 1 MB of data. This was quickly followed by a smaller version of the same design, the 5.25-inch (133 mm) floppy, which could store about the same amount of information using higher-density media and recording techniques.In the early 1980s, the 3.5-inch (90 mm) floppy, or micro floppy, came on the market, and this type became the dominant storage medium for personal computers for many years. Each of these floppy disks required a different type of floppy disk drive. These were typically built into the computer case itself.Floppy disks were quite vulnerable. The disk medium was very sensitive to dust, moisture, and heat. The flexible plastic carrier was also not very sturdy. The hard plastic case of the 3.5-inch floppy presented a substantial improvement in this respect. The most common format of this floppy became the double-sided, high-density 1.44 MB disk drive.