(1) Processing & storage The brains of the computer are the processing and memory devices, which are installed in the case or system cabinet I.

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1 (1) Processing & storage The brains of the computer are the processing and memory devices, which are installed in the case or system cabinet I. Case & power supply: Also known as the system unit, the case or system cabinet is the box that houses the processor chip (CPU), the memory chips, and the motherboard with power supply, as well as some secondarystorage devices floppy-disk drive (if any), hard disk drive, and CD or DVD drive, as we will explain. The case generally comes in desktop or tower models. It includes a power supply unit and a fan to keep the circuitry from overheating. II. Motherboard: Also called the system board, the motherboard is the main circuit board in the computer. The motherboard has expansion slots for expanding the PC s capabilities which give you places to plug in additional circuit boards, such as those for video, sound, and communications (modem). The system board controls communications for the entire computer system. All external devices including the keyboard, mouse, and monitor connect to the system board. It acts as a data path and traffic monitor, allowing the various components to communicate efficiently with one another. On a desktop computer, the system board is typically located at the bottom of the system unit or along one side. It is a large flat circuit board covered with a variety of different electronic components including sockets, slots, and bus lines.

2 Sockets provide a connection point for small specialized electronic parts called chips. Chips consist of tiny circuit boards etched onto squares of sand like material called silicon. These circuit boards can be smaller than the tip of your finger. A chip is also called a silicon chip, semiconductor, or integrated circuit. Chips are mounted on carrier packages. These packages either plug directly into sockets on the system board or onto cards that are then plugged into slots on the system board. Sockets are used to connect the system board to a variety of different types of chips, including microprocessor and memory chips. Slots provide a connection point for specialized cards or circuit boards. These cards provide expansion capability for a computer system. For example, a wireless networking card plugs into a slot on the system board to provide a connection to a local area network.

3 III. Connecting lines called bus lines provide pathways that support communication among the various electronic components that are either located on the system board or attached to the system board. Processor chip: It may be small and not look like much, but it could be the most expensive hardware component of a build-it-yourself PC and doubtless the most important. A processor chip (CPU, for central processing unit) is a tiny piece of silicon that contains millions of miniature electronic circuits. See figure below. The term has been used in the computer industry at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry. Chip processing capacities are often expressed in word sizes. A word is the number of bits (such as 16, 32, or 64) that can be accessed at one time by the CPU. The more bits in a word, the more data a computer can process at one time. As mentioned previously, eight bits group together to form a byte. A 32- bit-word computer can access 4 bytes at a time. A 64-bit-word computer can access 8 bytes at a time. Therefore, the computer designed to process 64-bit words has greater processing capacity. Other factors affect a computer s processing capability including how fast it can process data and instructions.

4 The processing speed of a microprocessor is typically represented by its clock speed, which is related to the number of times the CPU can fetch and process data or instructions in a second. Older microcomputers typically process data and instructions in millionths of a second, or microseconds. Newer microcomputers are much faster and process data and instructions in billionths of a second, or nanoseconds. Supercomputers, by contrast, operate at speeds measured in picoseconds 1,000 times as fast as microcomputers. Logically, the higher a microprocessor s clock speed, the faster the microprocessor. However, some processors can handle multiple instructions per cycle or tick of the clock; this means that clock speed comparisons can only be made between processors that work the same way. The two most significant recent developments in microprocessors are the 64- bit processor and the multicore chip. Until recently, 64-bit processors were primarily used in large mainframe and supercomputers. All of that is changing as 64-bit processors have become standard for most of today s desktop and laptop computers. The other recent development is the multicore chip. As mentioned previously, a traditional microcomputer s CPU is typically contained on a single microprocessor chip. A new type of chip, the multicore chip, can provide two or more separate and independent CPUs. These chips allow a single computer to run two or more operations at the same time. For example, a dual-core process could have one core computing a complex Excel spreadsheet while the other is running a multimedia presentation. More significantly, however, is the potential for microcomputers to run very large, complex programs that previously required expensive and specialized hardware. For multicore processors to be used effectively, computers must understand how to divide

5 tasks into parts that can be distributed across each core an operation called parallel processing. H.W: compare between core i5 & core i7