The system unit
- 1. The System Unit The system unit is a case that contains electronic components of the computer used to process data. System units are available in a variety of shapes and sizes. The case of the system unit, sometimes called the chassis, is made of metal or plastic and protects the internal electronic components from damage. All computers and mobile devices have a system Unit.
- 3. The Motherboard The motherboard, sometimes called a system board, is the main circuit board of the system unit. Many electronic components attach to the Motherboard, others are built into it.
- 4. Processor The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer. The processor significantly impacts overall computing power and manages most of a computer’s operations. Most processor chip manufacturers now offer multi- core processors. A processor core, or simply core, contains the circuitry necessary to execute instructions. Processors contain a control unit and an arithmetic logic unit (ALU). These two components work together to perform processing operations.
- 5. The Control Unit The control unit is the component of the processor that directs and coordinates most of the operations in the computer. it interprets each instruction issued by a program and then initiates the appropriate action to carry out the instruction. Types of internal components that the control unit directs include the arithmetic/logic unit , registers, and buses.
- 6. The Arithmetic Logic Unit The arithmetic logic unit (ALU), another component of the processor, performs arithmetic, comparison, and Other operations. Arithmetic operations include basic calculations such as addition, subtraction, multiplication, and division. Comparison operations involve comparing one data item with another to determine whether the first item
- 7. Machine Cycle For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle (1) fetching (2) Decoding (3) executing (4) storing
- 8. • Fetching is the process of obtaining a program instruction or data item from memory. • Decoding refers to the process of translating the instruction into signals the computer can execute. • Executing is the process of carrying out the commands. • Storing, in this context, means writing the result to memory (not to a storage medium).
- 10. Registers A processor contains small, high-speed storage locations, called registers, that temporarily hold data and instructions. Registers are part of the processor, not part of memory or a permanent storage device. Processors have many different types of registers, each with a specific storage function.
- 11. The System Clock The processor relies on a small quartz crystal circuit called the system clock to control the timing of all computer operations. the system clock generates regular electronic pulses, or ticks, that set the operating pace of components of the system unit. Each tick equates to a clock cycle The pace of the system clock, called the clock speed, is measured by the number of ticks per second
- 12. Processor Cooling Heat sinks pipes and liquid cooling technologies often are used to help dissipate processor heat. A heat sink is a small ceramic or metal component with fins on its surface that absorbs and disperses heat produced by electrical components such as a processor .
- 13. Heat Sinker
- 14. Parallel Processing Parallel processing is a method that uses multiple processors simultaneously to execute a single program or task .
- 16. Memory • Memory consists of electronic components that store instructions waiting to be executed. • Memory stores three basic categories of items 1-: the operating system and other • system software that control or maintain the computer and its devices . 2-:application programs that carry out a specific task such as word processing . 3-:The data being processed by the application programs and resulting information.
- 17. Memory Sizes 1 Kilobyte = 1,024 1 Megabyte =1,048,576 1 Gigabyte =1,073,741,824 1 Terabyte =1,099,511,627,776
- 18. Types of Memory volatile memory Nonvolatile memory
- 19. Types of Memory RAM (random access memory), also called main memory, consists of memory chips that can be read from and written to by the processor and other devices.
- 20. Types of Memory TWO basic types of RAM 1-: Dynamic RAM 2-:Static RAM
- 21. memory modules There are three types of memory modules. 1-:SIMMs(single inline memory module) 2-:DIMMs(dual inline memory module) 3-:RIMMs(Rambus inlinememory module)
- 22. MEMORY MODULES
- 23. Types of Memory Cache Memory Cache Memory helps speed the processes of the computer because it stores frequently used instructions and data.
- 24. types of memory cache L1 cache L2 cache
- 25. types of memory cache • L1 cache L1 cache usually has a very small capacity ranging from 8 KB to 128 KB. The more common sizes for personal computers are 32 KB or 64 KB. • L2 cache L2 cache is slightly slower than L1 cache but has a much larger capacity, ranging from 64 KB to 16 MB.
- 26. Types of Memory ROM(Read only memory) ROM is nonvolatile, which means its contents are not lost when power is removed from the computer. In addition to computers, many devices contain ROM chips. For example, ROM chips in printers contain data for fonts.
- 27. TYPES OF ROM There are two types of ROM 1-:PROM 2-:EEPROM
- 28. TYPES OF ROM • PROM (programmable read-only memory) A PROM chip is a blank ROM chip on which a programmer can write permanently. Programmers use microcode instructions to program a PROM chip. Once a programmer writes the microcode on the PROM chip, it functions like a regular ROM chip and cannot be erased or changed.
- 29. TYPES OF ROM EEPROM (electrically erasable programmable read-only memory) EEPROM chip, allows a programmer to erase the microcode with an electric signal.
- 30. Types of Memory Flash Memory Flash memory is a type of nonvolatile memory that can be erased electronically and rewritten, similar to EEPROM.
- 31. Types of Memory • CMOS(complementary metal-oxide semiconductor) (CMOS pronounced SEE-moss) technology because it provides high speeds and consumes little power. CMOS technology uses battery power to retain information even when the power to the computer is off. Battery-backed CMOS memory chips, for example, can keep the calendar, date, and time current even when the computer is off. The flash memory chips that store a computer’s startup information often use CMOS technology.
- 32. Memory Access Times Access time is the amount of time it takes the processor to read data, instructions, and information from memory. A computer’s access time directly affects how fast the computer processes data.
- 33. Expansion Slots and Adapter Cards • Expansion Slots An expansion slot is a socket on the motherboard that can hold an adapter card. • Adapter Cards An adapter card, sometimes called an expansion card, is a circuit board that enhances functions of a component of the system unit and/or provides connections to peripherals.
- 34. ADAPTER CARD
- 35. Removable Flash Memory A type of memory which can easily insert and remove from a slot of a personal computer. A memory card is a removable flash memory device, usually no bigger than 1.5" in height or width, that you insert and remove from a slot in a personal computer, game console, mobile device, or card reader/writer.
- 37. Ports and Connectors • PORTS A port is the point at which a peripheral attaches to or communicates with a system unit so that the peripheral can send data to or receive information from the computer. • CONNECTORS A connector joins a cable to a port. A connector at one end of a cable attaches to a port on the system unit, and a connector at the other end of the cable attaches to a port on the peripheral.
- 39. Ports and Connectors • USB Ports A USB port, short for universal serial bus port, can connect up to 127 different peripherals together with a single connector. Devices that connect to a USB port include the following: mouse, printer, digital camera, scanner, speakers, portable media player, optical disc drive, smart phone, PDA, game console, and removable hard disk.
- 40. Ports and Connectors FireWire Ports FireWire port is similar to a USB port in that it can connect multiple types of devices that require faster data transmission speeds such as digital video cameras, digital VCRs, color printers, scanners, digital cameras, and DVD drives, to a single connector.
- 41. Ports and Connectors Bluetooth Port Bluetooth technology uses radio waves to transmit data between two devices. A Bluetooth wireless port adapter that will convert an existing USB port into a Bluetooth port .
- 42. BLUETOOTH DEVICE
- 43. Ports and Connectors SCSI Port A special high-speed parallel port called a SCSI port, allows you to attach SCSI(pronounced skuzzy) peripherals such as disk drives and printers.
- 44. Ports and Connectors • eSATA Port • An eSATA port, or external SATA port, allows you to connect an external SATA (Serial Advanced Technology Attachment) hard disk to a computer. SATA hard disks are popular because of their fast data transmission speeds. • eSATA connections provide up to six times faster data transmission speeds than external hard disks attached to a computer’s USB or FireWire port .
- 45. Ports and Connectors IrDA Port IrDA port is used infrared signals to transmit data one device to another device. Devices that use IrDA ports include a smart phone, PDA, keyboard, mouse, and printer. Several of these devices use a high-speed IrDA port, sometimes called a fast infrared port.
- 46. IrDA ports
- 47. Ports and Connectors • Serial Ports A serial port is a type of interface that connects a device to the system unit by transmitting data one bit at a time. • MIDI Port A special type of serial port that connects the system unit to a musical instrument , such as an electronic keyboard, is called a MIDI port.
- 48. Port Replicators and Docking Stations Port Replicators A port replicator is an external device that provides connections to peripherals through ports built into the device. The mobile user accesses peripherals by connecting the port replicator to a USB port or a special port on the mobile computer.
- 49. Buses Buses are used to transfer bits from input devices to memory, from memory to the processor, from the processor to memory, and from memory to output or storage devices.
- 50. BUSES
- 51. PARTS OF BUSES • There are two parts of buses • DATA BUS • ADDRESS BUS 1-:Data Bus The data bus is used to transfer actual data. 2-:Address Bus • The address bus is used to transfer information about where the data should reside in memory.
- 52. TYPES OF BUSES • There three types of buses • System Bus • Backside Bus • Expansion Bus 1-:System Bus • A system bus, also called the front side bus ( FSB), is part of the motherboard and connects the processor to main memory.
- 53. TYPES OF BUSES 2-:Backside Bus A backside bus ( BSB) connects the processor to cache. 3-:Expansion Bus An expansion bus allows the processor to communicate with peripherals.