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4. Chapter. Hardware: The CPU & Storage. Microchips, Miniaturization, & Mobility. Vacuum Tubes vs. Transistors Vacuum tubes were the original logic gates of computers They looked like light bulbs, were hot, and burned out like them too
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4 Chapter Hardware: The CPU & Storage © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Microchips, Miniaturization, & Mobility • Vacuum Tubes vs. Transistors • Vacuum tubes were the original logic gates of computers • They looked like light bulbs, were hot, and burned out like them too • The original transistors were 1/100th the size of vacuum tubes (less power used, faster, more reliable too) • Transistors vs. Integrated Circuits • Compare 1955’s 45 lb “portable” color TV to today’s 7 oz Casio 2.3 inch color TV • One integrated circuit contains thousands of transistors © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Microchips, Miniaturization, & Mobility • Semiconductor • A material whose electrical properties are intermediate between a good conductor and a nonconductor of electricity • Perfect substrate for overlay of complex circuits • Microchips are made from semiconductors • Contain millions of microminiature integrated circuits © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Microchips, Miniaturization, & Mobility • Microprocessor • The miniaturized circuitry of an entire computer processor on a single chip • Contains the CPU, which processes data • Microcontroller or Embedded Computer • A tiny specialized microprocessor installed in “smart” appliances and automobiles © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics • Binary System: the basic unit of computing • Uses just two numbers: 0 and 1 • All data and program instructions in the computer are represented as binary • Bit: each 0 or 1 is a bit • Byte: a group of 8 bits • Kilobyte: ~1,000 (1,024) bytes • Megabyte: ~1 Million (1,048,576) bytes • Gigabyte: ~1 Billion (1,073,741,824) bytes • Terabyte: ~ 1 Trillion (1,009,511,627,576) bytes • Petabyte: ~ 1 quadrillion bytes • Exabyte: ~ 1 quintillion bytes • All the printed material in the world is ~ 5 exabytes © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics • Binary coding schemes assign a unique binary code to each letter • EBCDIC • Requires 8 bits per character • Used for IBM mainframes • ASCII • Requires 7 or 8 bits per character, depending on the version • 8 bit Extended ASCII provides 256 characters • Used for PCs, Unix hosts, Macs • Unicode • Requires 16 bits per character • Handles 65,536 characters © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics Discussion Question: If the 7 data bits are 1101011, and the modem is sending odd parity, what should the parity bit be set to? Answer: Since the data bits add up to 5, an odd number, the parity bit will be 0. • Error Checking: Parity Bits • Used in modems & communications to verify correctness • One check bit is added to 7 bit byte • The check bit is defined as either odd or even • For odd parity, if the data sent is correct, the parity bit plus the first 7 data bits is an odd number • For even parity, if the data sent is correct, the parity bit plus the first 7 data bits is an even number © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics • Machine Language • A binary-type programming language built into the CPU that is run directly by the computer • Each CPU type has its own machine language • Language Translators • System programs convert the programming instructions for you into machine language © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The BasicsComputer Terms • Names • Bay • Power Supply • Surge Protector • Voltage Regulator • UPS • Motherboard • Microprocessor • Chipset • Definitions • Shell or opening used for the installation of electrical equipment. • This converts AC to DC to run the computer. • Protects the computer from being damaged by power spikes. Plug your computer into one. • Protects a computer against brownouts or low power conditions that happen a lot in summer. • Uninterruptible Power Supply. Battery-operated device that provides power for a time when there is a blackout. • The main system board of the computer. • The miniaturized circuitry of a computer processor. • Groups of interconnected chips on the motherboard that control information flow between the microprocessor and other system components connected to the motherboard. © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics • The CPU • Older CPUs processing speeds are in MegaHertz • 1 MHz = 1 Million ticks per second • Current CPUs processing speeds are in GigaHertz • 1 GHz = 1 Billion ticks per second • The faster a CPU runs, the more power it consumes, and the more heat it generates © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
The System Unit: The Basics • The CPU Continued • Mainframe and minicomputer speed is measured in MIPS • MIPS stands for millions of instructions per second • Workstations perform at 100 MIPS or more • Mainframes now perform as fast as 981,024 MIPS • Supercomputer processing speed is measured in flops • Flops stands for floating point operations per second • Los Alamos Lab’s new Roadrunner cranks out 1 petaflop or 1,000 trillion operations per second. © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitParts of the CPU • Definition • The number of bits the processor can process at any one time • The part of the CPU that deciphers instructions and carries them out • The ALU performs mathematical and logical operations and controls the speed of them • High-speed storage areas that temporarily store data during processing • Electrical data roadways used to transmit bits within the CPU and between CPU and other motherboard components Name Word size Control unit Arithmetic Logic Unit Registers Buses © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitHow Memory Works Memory Chip • RAM • ROM • CMOS • Flash Explanation • Random Access Memory chips are volatile and hold: • Software instructions • Data before & after the CPU processes it • Read only memory • Cannot be written on or erased without special equipment • Are loaded at factory with fixed start-up instructions • Complementary Metal Oxide Semiconductor • Powered by a battery • Contains time, date, calendar, boot password • Nonvolatile memory that can be erased and reprogrammed more than once • Doesn’t require a battery • Used in newer PCs for BIOS instructions © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitTypes of RAM RAM Types • DRAM • SDRAM • SRAM • DDR-SDRAM • SIMM • DIMM Explanation • Dynamic RAM must be constantly refreshed by the CPU or it loses its contents • Synchronous Dynamic RAM is synchronized by the system clock and is much faster than DRAM • Static RAM is faster than DRAM and retains its contents without having to be refreshed by CPU • Double-data rate synchronous dynamic RAM • Single Inline Memory Module has RAM chips on only one side • FPM is fast page mode type • EDO is extended data output; is faster than FPM • Dual Inline Memory Module has chips on both sides © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitSpeeding up Processing • The CPU works much faster than RAM • So it could sit there waiting for information • Cache temporarily stores instructions and data that the processor uses frequently to speed up processing • Level 1 cache is part of the microprocessor • Holds 8 to 256 kb • Faster than Level 2 cache • Level 2 cache is SRAM external cache • Holds 64 kb to 2 Mb • Level 3 cache is on the motherboard • Comes on very high-end computers © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitSpeeding up Processing Method • Interleaving • Bursting • Pipelining • Superscalar Architecture • Hyperthreading Description • CPU alternates communications between two or more memory banks • CPU grabs a block of data from memory instead of retrieving one piece at a time • CPU doesn’t wait for one instruction to complete before fetching its next instruction • The computer can execute more than one instruction per clock cycle • A technique used in superscalar architecture in which the OS treats the microprocessor as though it is two microprocessors © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitPorts Port Type • Serial Port • Parallel Port • SCSI Port • USB Port Description • Used to transmit slow data over long distances • Sends data sequentially, one bit at a time • Used to connect keyboard, mouse, monitors, dial-up modems • For transmitting fast data over short distances • Transmits 8 bytes simultaneously • Connects printers, external disks, backups • Small Computer System Interface • Connects up to 7 devices in a daisy chain • Transmits data 32 bits at a time • Universal Serial Bus can theoretically connect up to 127 peripheral devices in a daisy chain © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitUSB • Goals • Be low-cost • Be able to connect lots of devices • Be hot swappable • People hate rebooting because it takes time • Hot swapping means a device can be connected/disconnected without rebooting • Permit plug and play • Devices are automatically configured when they are installed – no need to download new drivers © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitUSB Continued • Standards • USB 1.1 – the original standard • USB 2.0 – the current standard for new PCs • USB On The Go (OTG) – currently under development • Connectors • A – in USB Type 1.1 and 2.0 • B – in USB Type 1.1 and 2.0 • Mini B – in USB Type 2.0 • Mini A – in USB OTG used for smaller peripherals like cellphones © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitSpecialized Expansion Ports Port Type • FireWire • MIDI • IrDA • Bluetooth • Ethernet Description • Intended for devices working with lots of data • Used for camcorders, DVD players, TVs • Handles up to 400 megabits per second • Musical Instrument Digital Interface • Connects musical instruments • Used in creating, recording, editing, performing music • Infrared Data Association: Infrared ports used to make a cableless connection • Uses short-range radio waves that transmit up to 30 ft • Connects computers to printers, keyboards, headsets, even refrigerators • Named after King Harald Bluetooth, son of Gorm, who united the Norway and Denmark. Ruled 910-940 A.D. • The standard for linking all devices in a Local Area Network © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System UnitExpansion Cards © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
More on the System Unit Expansion Buses Bus • PCI bus • AGP Bus Description • Peripheral Component Interconnect • For high-speed connections • 32 or 64 bits wide • Typically used for sound cards, modems, high-speed network cards • Accelerated Graphics Port • Twice the speed of PCI bus • For Video and 3-D graphics cards © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary Storage Storage Types • Floppy and Zip disks • Hard disks • Optical disks • Magnetic tape • Smart Cards • Flash memory • Online secondary storage Descriptions • Removable disks. • Floppies store 1.44 MB • Zip disks store 100, 250, or 750 MB • Made from thin rigid metal covered with magnetizable substrate. Most disks have 2 or more platters • Removable CDs and DVDs • Thin plastic tape coated with magnetizable substance • Like a credit card, but contains a microprocessor and memory chips • Nonvolatile memory – no moving parts • Lets you store data on an online vendor’s server © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageFloppies and Zip Disks • Floppies • Flat piece of mylar plastic inside a 3.5” plastic case • Store about 1.44 MB • Have a write-protect notch • Data is recorded in tracks: concentric recording bands • Formatting breaks the tracks into small wedge-shaped sectors • Read/Write head transfers data between the computer and disk • Floppies DO wear out! • Zip Disks • Disks with a high-quality magnetic coating • Store 100, 250, or 750 MB • Require a Zip drive; won’t work on floppy drives • Used to store larger files than floppies can hold • Zip disks wear out too! © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageHard Disks • Thin, rigid metal, glass, or ceramic platters covered with a substance that allows data to be held in the form of magnetized spots • The more platters there are, the higher the drive capacity • Store data in tracks, sectors, and clusters • Formatting creates a file allocation table that maps files to clusters or inodes • Typical file systems are VFAT & NTFS for Windows, HFS and ext2 for Unix • Drive heads ride on .000001” cushion of air, and can crash! • Important data should always be backed up! © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageHard Disks • Hard Disk Types: • External Hard Disks – a freestanding disk drive • Removable Hard Disk – inserted into a cartridge drive on the PC • Hard Disk Controllers • EIDE – Enhanced Integrated Drive Electronics • Supports up to 4 disks at 137 GB per disk • Marketed as SATA, Fast ATA, Ultra ATA, ATA-2, ATA/100 • SCSI – Faster than EIDE controllers • Fibre Channel – used in large servers – faster and costlier than SCSI © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageOptical Disks • CDs and DVDs are Optical disks • Data is written and read using lasers, not a disk head • CD-ROM is Compact Disk Read-Only Memory • CD-R is used for recording only once • CD-RW is an erasable optical disk that can both record and erase data over and over again • DVD is a CD-style disk with extremely high capacity • Stores 9.4 or more GB • DVD-R is used for recording only once • DVD-RW, DVD-RAM, DVD+RW are reusable DVDs © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageMagnetic Tape • Thin plastic tape coated with a substance that can be magnetized • Store terabytes of data • Used in the form of tape cartridges • Still popular for large backups because of their large data capacity • But don’t get it near a magnet as that will erase it! © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageSmart Cards • Resembles a credit card, but contains a microprocessor and memory chips • May function on three levels: credit, debit, and/or personal information • Holds more information than standard magnetic-strip credit cards; 8 – 40 MB of data • Contact smart cards • Must be swiped through card readers • Can wear out from use • Contactless smart cards • Read when held in front of a low-powered laser © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageFlash Memory • Nonvolatile memory with no moving parts • But the electronics can wear out • Available as • Flash memory cards • Insert these into a flash port of a camera, handheld PC, smartphone • Flash memory sticks • A form of flash memory that plugs into a memory stick port • Flash memory drives • A finger-sized module of flash memory • Plugs into the USB port of most PCs and Macintoshes © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Secondary StorageOnline Secondary Storage What are some of the disadvantages when using online secondary storage? • Allows you to use the internet to back up your data • Sign up with a vendor and receive access to software that allows you to upload your data to that company’s server • Files should be encrypted to maintain security • Use only for vital files that require immediate availability • Use tape, removable hard disk cartridges, zip disks, optical storage or tape for normal backup © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Future Developments in Processing & Storage • Moore’s Law • Gordon Moore predicted the number of transistors on a silicon chip will double every 18 months • It has held up since the 1960s! © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Future Developments in Processing & Storage New Technology • M-RAM • OUM • Nanotechnology • Optical Computing • DNA Computing • Quantum Computing Description of Processing Technology • Magnetic RAM uses miniscule magnets rather than electrical charges • Ovonic Multiplied Memory stores bits by generating different levels of low and high resistance on a glossy material • Tiny machines work at a molecular level to make nanocircuits • Uses lasers and light, not electricity • Uses strands of synthetic DNA to store data • Based on quantum mechanics and stores information using particle states © 2010 The McGraw-Hill Companies, Inc. All rights reserved.
Future Developments in Processing & Storage New Technology • Higher-density disks • Molecular electronics Description of Storage Technology • Higher Density Disks • Blank CDs are replacing floppy disks since they hold up to 700 MB and cost < $1 each • DVD disks hold up to 9.4 GB of data currently • Perpendicular recording technology allows 25% - 100% more data to be stored on the same disk • Polymer memory creates chips that store data on plastics • Nonvolatile memory • Data is stored based on polymer’s electrical resistance © 2010 The McGraw-Hill Companies, Inc. All rights reserved.