Chapter 4 Inside the Computer Computers: Information Technology in Perspective, 11e Larry Long and Nancy Long Chapter 4 Inside the Computer Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Objectives Once you have read and studied this chapter, you will have learned: How data are stored and represented in a computer system. The function of and relationships between the internal components of a personal computer, including the motherboard, processor, RAM and other memories, ports, buses, expansion boards, and PC cards. How to distinguish processors by their word size, speed, and memory capacity. Several approaches to processor design. Copyright Prentice Hall, Inc.

Why this chapter is important to you! Learning about computers can help you make smart purchasing decisions when it comes time to buy the next computer To get what you need and want out of a computer you have to know what you are doing Details about computer components is a must for making informed decisions about purchases Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Going Digital Analog A computer is: A CD player Video player Family photo album And more… Digitizing means converting analog signals to 1s and 0s Digital Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Binary Digits: 1 and 0 Binary digits represent letters, numbers, colors, shapes, and more The on state is 1 The off state is 0 RAM Presence or absence of an electrical charge DISK Magnetic arrangement CD Permanent microscopic pits Fiber Optic Pulses of light Only 2 states possible On Off Copyright Prentice Hall, Inc.

Encoding Systems: Bits and Bytes Most popular encoding system for PCs Characters equate to a series of 1s and 0s Letter B= 01000010 7-Bit ASCII can represent up to 128 characters The PC byte is 8 bits and can represent up to 256 configurations The first 128 ANSI codes represent needs of the Windows applications The new Unicode is a 16-bit code allowing for 65,526 characters Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Hexadecimal Hexadecimal or base-16 is used as a shorthand to display binary contents of RAM or disk storage A single hexadecimal digit represents four binary digits Two hexadecimal digits can be used to represent an eight-bit byte 0011 1111 0111 1010 Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. The PC System Unit The PC system unit Houses all electronic components Usually a metal and plastic upright box called tower or a notebook’s shell Copyright Prentice Hall, Inc.

The Motherboard: The Central Nervous System The motherboard is a single circuit board and houses: Processor Chipset Memory Chips Expansion Slots Motherboard provides a path (bus) for the processor to communicate with other components Copyright Prentice Hall, Inc.

The Processor: Computer on a Chip It is a self-contained integrated circuit First PC used an Intel 8088 chip What came after: Intel 286, 386, and 486 Pentium, Pentium Pro, Pentium II, III, and IV Pentium Celeron or Itamium Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Inside the Processor The processor or CPU, as it is also called: Reads and interprets programs Directs operations Controls the flow of programs and data Copyright Prentice Hall, Inc.

The Arithmetic and Logic Unit Performs computations: Addition Subtraction Multiplication Division Results of computations are placed in the accumulator Examples: Payroll deductions Bank statement balances Copyright Prentice Hall, Inc.

RAM: Digital Warehouse Volatile & temporary Programs/data are loaded into RAM storage High-speed holding area Ram Types: SDRAM DDR SDRAM RDRAM Chips: SIMM DIMM RIMM Copyright Prentice Hall, Inc.

Cache and Other High-Speed Memories Cache memory High-speed holding area that would be retrieved more frequently Level 1 Built into the processor Level 2 Ultra-fast memory ROM Read only Cannot be altered Flash Type of PROM Can be altered Survives electrical interruptions Copyright Prentice Hall, Inc.

What Happens Inside: Unraveling the Mystery Instruction Time Execution Fetch Instruction Execute Instruction Place Result in Memory Decode Instruction BASIC programming Intuitive instructions Machine language Translated Instruction cycle Executing instructions Pipelining Begin next execution before first is completed Copyright Prentice Hall, Inc.

Putting It All Together Expansion Slots Expands the PC Such as: Extra ports Modem Video Copyright Prentice Hall, Inc.

Putting It All Together Bus Support Type: PCI Links directly to common bus Universal Serial Bus Permits up to 127 devices 1394 Permits 63 external 30 times faster than USB SCSI Permits up to 15 devices AGP Direct link for graphics adapter Copyright Prentice Hall, Inc.

Putting It All Together Ports Serial Parallel SCSI USB 1394 Keyboard/Mouse IrDA Copyright Prentice Hall, Inc.

PC Growth: Adding Capabilities Expansion Boards Graphics Adapter Sound Data/Voice/Fax USB hub Network Interface card Video Capture PCMCIA Copyright Prentice Hall, Inc.

Describing the Processor and Its Performance: Word Size Describes the number of bits that are handled Most computers have 64-bit internal processing, but only a 32-bit bus path Copyright Prentice Hall, Inc.

Describing the Processor and Its Performance: Core Speed Speed of a computer PCs Measured in GHz Billions of clock cycles per second Workstations & servers MIPS Millions of instructions per second Supercomputers FLOPS Trillions of instructions per second Copyright Prentice Hall, Inc.

Describing the Processor and Its Performance: Bus Speed Measured in cycles per second Operates at MHz speed Usually around 250 to 600 MHz for modern PCs Copyright Prentice Hall, Inc.

Describing the Processor and Its Performance: Memory Capacity Kilobits (Kb) 1024 bytes Megabytes (MB) 1,048,576 bytes Gigabytes (GB) About 1 billion bytes Terabytes (TB) About 1 trillion bytes Copyright Prentice Hall, Inc.

Describing the Differences Parallel Processing Multiple processors Neural Networks Processor that mimics the human brain Grid Computing Shared processing Copyright Prentice Hall, Inc.

Copyright Prentice Hall, Inc. Summary Going digital Analog Digital The PC system unit System Unit Describing the processor and its performance MHz GHz MIPS FLOPS Processor design Parallel Neural Grid Copyright Prentice Hall, Inc.