4-1 McGraw-Hill Hardware: The CPU & Storage © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 4 McGraw-Hill 4.1 Microchips, Miniaturization, & Mobility 4-3 Vacuum Tubes Vacuum tubes were the original logic gates of computers; they controlled the flow of electricity in circuits. They looked like light bulbs, were hot, and burned out quickly. A circuit is a closed path that can be flowed by electric current. Transistors Replaced Vacuum Tubes The original transistors, tiny electronic switches, were 1/100th the size of vacuum tubes (less power used, faster, more reliable) Transistors form part of an integrated circuit--all the parts of an electronic circuit embedded on a single silicon chip. One integrated circuit contains more than a million transistors. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.1 Microchips, Miniaturization, & Mobility 4-4 Silicon & Semiconductors Silicon: A semiconductor made of clay and sand Semiconductor: A material whose electrical properties are intermediate between a good conductor and a nonconductor of electricity Perfect underlayer for highly conductive, complex circuits Microchips (Microprocessors) are made from semiconductors Chip: A tiny piece of silicon that contains millions of microminiature integrated electronic circuits © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.1 Microchips, Miniaturization, & Mobility 4-5 Miniaturization Miracles Microchips Microprocessors Store and process data in electronic devices The miniaturized circuitry of an entire computer processor (“brain”) on a single chip Contains the central processing unit (CPU), which processes data into information The development of microchips and processors has enabled the development of small, mobile electronic devices. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-6 4.2 The System Unit: The Basics Binary System: the basic data-representation method for computers uses just two numbers: 0 and 1, representing the off/on states of electricity or light pulses. 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 = 1 character, digit, or other value 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-7 4.2 The System Unit: The Basics Binary coding schemes assign a unique binary code to each character. 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 Commonly used for microcomputers Unicode Requires 16 bits per character Handles 65,536 characters—used for Chinese and Japanese © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-8 4.2 The System Unit: The Basics Machine Language A binary-type programming language (0s and 1s) built into the CPU that is run directly by the computer Each CPU type has its own machine language Language Translators The computer’s system software converts higher-level language instructions and data into machine language so that the processor can “understand” what to do. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-9 4.2 The System Unit: The Basics © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-10 4.2 The System Unit: The Basics © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-11 4.2 The System Unit: The Basics Computer Terms Names Bay Power Supply Surge Protector Voltage Regulator UPS Motherboard Microprocessor Chipset Definitions Opening in the computer cabinet 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 limited time when there is a blackout. The main system board of the computer (also systemboard). 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. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-12 4.2 The System Unit: The Basics Two main types of microprocessors are made for microcomputers--one for PCs and one for Macs. Microprocessor manufacturers are Intel, AMD, Motorola/Freescale, and IBM. Multicore processors have more than one processor “core” on a silicon chip, which allows computers to ru faster. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-13 4.2 The System Unit: The Basics Processing Speeds Every microprocessor has a system clock built in that controls the chip’s processing speed. Older CPU processing speeds are in megahertz Current CPU processing speeds are in gigahertz 1 MHz = 1 million cycles per second 1 GHz = 1 billion cycles per second The faster a CPU runs, the more power it consumes, and the more heat it generates © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-14 4.2 The System Unit: The Basics Processing Speeds (continued) Workstation and mainframe speeds are 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 has a speed of 1,105 teraflops, or 1,000 trillion operations per second. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-15 4.3 More on the System Unit Parts of the CPU Name Definition Word size The number of bits the processor can process at any one time CPU The central processing unit (chip) has two parts; the control unit and the ALU Control unit The part of the CPU that deciphers instructions and carries them out Arithmetic Logic Unit (ALU) The part of the CPU that performs mathematical and logical operations Registers High-speed storage areas that temporarily store data during processing Buses Electrical data roadways used to transmit bits within the CPU and between CPU and other motherboard components © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-16 4.3 More on the System Unit Memory Two type of storage: primary and secondary Primary storage = “memory,” “main memory,” “RAM”; this type of memory is temporary and volatile Secondary storage = “storage” disks and tape; this type of memory is relatively permanent and nonvolatile © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-17 4.3 More on the System Unit How Memory Works Primary Memory Chips RAM ROM CMOS Flash Explanation Random Access Memory chips are volatile and hold: a. Software instructions b. Data before & after the CPU processes it Read Only Memory a. Cannot be written on or erased without special equipment b. Are loaded at factory with fixed (permanent) startup instructions (BIOS), that tell the computer how to load the operating system Complementary Metal Oxide Semiconductor a. Powered by a battery b. Contains time, date, calendar, boot password Nonvolatile memory that can be erased and reprogrammed more than once a. Doesn’t require a battery b. Used in newer PCs for BIOS instructions © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-18 Types of RAM RAM Chip Types DRAM 1. SDRAM 2. Synchronous Dynamic RAM is synchronized by the system clock and is much faster than DRAM SRAM 3. Static RAM is faster than DRAM and retains its contents without having to be refreshed by CPU DDR-SDRAM 4. SIMM 5. DIMM 6. Double-data rate synchronous dynamic RAM; type used most commonly in microcomputers Single Inline Memory Module has RAM chips on only one side; insert in expansion slot to increase RAM Dual Inline Memory Module has chips on both sides; insert in expansion slot to increase RAM Explanation Dynamic RAM must be constantly refreshed by the CPU or it loses its contents © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-19 4.3 More on the System Unit Speeding up Processing: Cache The CPU works much faster than RAM, so it often must wait 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 external cache Holds 64 kb to 2 Mb Level 3 cache is on the motherboard Comes on very high-end computers © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-20 4.3 More on the System Unit Virtual Memory—also used to speed up processing This type of memory is unused hard disk or optical (CD) space that the processor uses to extend the capacity of RAM The processor goes first to L1 cache, then L2 cache, then RAM, then virtual memory Each type of memory is slower than its predecessor © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-21 Speeding up Processing Additional Methods of Speeding up Processing Interleaving Bursting Pipelining Superscalar Architecture and Hyperthreading © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-22 4.3 More on the System Unit A port is a connecting socket or jack on the outside of the computer unit into which are plugged different kinds of cables Ports are used to connect peripheral devices © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-23 Ports Port Type Description Serial Port Used to transmit data slowly over long distances a. Sends data sequentially, one bit at a time b. Used to connect keyboard, mouse, monitors, dial-up modems For transmitting data quickly over short distances a. Transmits 8 bytes simultaneously b. Connects printers, external disks, tape backups Small Computer System Interface a. Connects up to 7 devices in a daisy chain b. Transmits data 32 bits at a time Universal Serial Bus can theoretically connect up to 127 peripheral devices in a daisy chain Parallel Port SCSI Port USB Port © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-24 4.3 More on the System Unit USB Goals Be low-cost Be able to connect lots of devices Be hot swappable People hate rebooting after connecting new devices, 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-25 4.3 More on the System Unit USB (continued) Standards USB 1.1--the original standard USB 2.0--the current standard for new PCs USB 3.0–for high-end computers USB OTG (On the GO) is used for small peripherals, such as cellphones 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-26 Specialized Expansion Ports Port Type Description FireWire Intended for devices working with lots of data; used for camcorders, DVD players, TVs MIDI Musical Instrument Digital Interface a. b. IrDA Bluetooth 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, and other devices Ethernet Multimedia The standard for linking all devices in a Local Area Network For special multimedia devices, such as gaming consoles, TVs, VCRs, speakers,digital projectors, etc. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-27 Expansion Cards If a computer uses closed architecture, no expansion cards can be added; if the computer uses open architecture, expansion cards can be inserted in expansion slots inside the computer, connected to the motherboard. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-28 Expansion Buses Expansion cards connect with different types of buses on the motherboard. Bus PCI bus AGP bus PCIe Express bus Description Peripheral Component Interconnect a. For high-speed connections b. 32 or 64 bits wide c. Typically used for sound cards, modems, high-speed network cards Accelerated Graphics Port a. Twice the speed of PCI bus b. Supports video and 3-D graphics cards Can outperform AGP and is more reliable © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4.3 More on the System Unit 4-29 Examples of Some Expansion Cards © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-30 4.3 More on the System Unit Types of Expansion Cards Graphics cards (for monitors) Sound cards (for speakers and audio output) Also called a video card, video RAM (VRAM), or video adapter Converts signals from computer into video signals that can be displayed as images on a monitor Used to convert and transmit digital sounds through analog speakers, microphones, and headsets Modem cards (for remote communication via phone lines) © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-31 4.3 More on the System Unit Types of Expansion Cards (continued) Network interface cards (for remote communication via cable) Allows the transmission of data over a cable network PC cards (for laptop computers) Thin, credit card-size flash memory devices used principally on laptop computers to expand capabilities © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-32 4.4 Secondary Storage Storage Types Descriptions Floppy disks Removable disks; Floppies store 1.44 MB; mostly obsolete, except on legacy systems Hard disks Made from thin rigid metal covered with magnetizable substrate. Most disks have 2 or more platters Optical disks Removable CDs and DVDs Magnetic tape Thin plastic tape coated with magnetizable substance Smart Cards Like a credit card, but contains a microprocessor and memory chips Flash memory Nonvolatile memory – no moving parts Online secondary storage Lets you store data on an online vendor’s server © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-33 4.4 Secondary Storage Floppy Disks Flat piece of mylar plastic inside a 3.5” plastic case Store about 1.44 MB 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 Not used much any more, except on some legacy systems © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-34 4.4 Secondary Storage Hard 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 Drive heads ride on .000001” cushion of air, and can crash! Important data should always be backed up! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-35 4.4 Secondary Storage Hard Disks (continued) Hard Disk Types: External Hard Disk – a freestanding disk drive Removable Hard Disk – inserted into a bay or a cartridge drive built into the computer’s system unit Hard Disk Controllers – special circuit boards that control the read/write heads and manage the flow of data to and from the hard disk EIDE – Enhanced Integrated Drive Electronics (e.g., SATA) SCSI – Faster than EIDE controllers Fibre Channel – Used in large servers – faster and costlier than SCSI © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-36 4.4 Secondary Storage Optical Disks CDs (compact disks) and DVDs (digital versatile/video disks) are optical disks Data is written and read using lasers, not a disk read/write head CD-ROM is Compact Disk Read-Only Memory CD-R (compact disk-recordable) is used for recording only once CD-RW (compact disk-rewritable)is an erasable optical disk that can both record and erase data over and over again © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-37 4.4 Secondary Storage Optical Disks (continued) DVD is a CD-style disk with extremely high capacity DVD-R (DVD-recordable) is used for recording only once DVD-RW, DVD-RAM, DVD+RW are reusable DVDs Blu-ray is an optical-disk format used to record, rewrite, and play back high-definition (HD) video, as well as to store large amounts of data. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-38 4.4 Secondary Storage Magnetic 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-39 4.4 Secondary Storage Smart Cards Resembles a credit card, but contains a microprocessor and memory chips May function on three levels: credit, debit, and/or personal information Storage capacity: around 10 MBs 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-40 4.4 Secondary Storage Flash Memory Nonvolatile memory with no moving parts 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 in, for example, a digital camera, camcorder, photo printer Flash memory drives (keychain drives) A finger-sized module of flash memory Plugs into the USB port of most PCs and Macintoshes Solid-state memory drives Have greater capacity than flash memory drives but are expensive © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-41 4.4 Secondary Storage Online Secondary Storage (Cloud 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 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-42 4.5 Future Developments in Processing & Storage New Technology Description of Processing Technology Application Virtualization Doing processing online instead of buying one’s own software and some hardware. Nanotechnology Tiny machines work at a molecular level to make nanocircuits Optical Computing Uses lasers and light, not electricity DNA Computing Uses strands of synthetic DNA to store data Quantum Computing Based on quantum mechanics and stores information using particle states Better Batteries Wireless charging of batteries, longer-lasting batteries © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill 4-43 4.5 Future Developments in Processing & Storage Future Developments in Secondary Storage Higher-density disks Perpendicular recording technology: stacking magnetic bits vertically on the surface of a platter (instead of horizontally, as usual) Molecular electronics– storage at the subatomic level Holograms, molecular magnets, bacteria © 2011 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill