STORAGE / INTERNET Spring 2010 What is Booting?
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STORAGE / INTERNET Spring 2010 What is Booting?

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  • Capacity= # of cylinders * # of heads * # of sectors * 512 bytes .91 of HDD capacity (manufacturer)

STORAGE / INTERNET Spring 2010 What is Booting? STORAGE / INTERNET Spring 2010 What is Booting? Presentation Transcript

  • STORAGE / INTERNET Spring 2010
  • What is Booting?
        • Cold boot Turning on computer that has been powered off
        • Warm boot Restarting computer that is powered on
    Warm boot from Windows desktop Warm boot from system unit
      • Process of starting or restarting a computer
    Image: © Shelly Cashman Vermaat 2004
  • Types of Memory
    • RAM ( temporary/volatile )
      • Random Access Memory (Primary Storage)
      • Storage for programs and data
      • “ Workspace” for the CPU
    • ROM ( permanent/non-volatile )
      • Read Only Memory – does not change
      • Startup instructions for computer (“Boot”)
      • Or – more specialized applications like games for small computers
  • Secondary Storage (or Storage)
    • The place where software and data are kept while not in use.
    • Common types:
      • Magnetic (hard drive)
      • Optical (CD, DVD)
      • Integrated Circuit (Flash memory USB sticks, Solid state drives, MP3 player)
  • Storage - Hard Disks Step 1. Circuit board controls movement of head actuator and a small motor. Step 2. Small motor spins platters while computer is running. Step 3. When software requests a disk access, read/write heads determine current or new location of data. Step 4. Head actuator positions read/write head arms over correct location on platters to read or write data. Image: © Shelly Cashman Vermaat 2004
  • Hard Disks clearance read/write head platter hair dust smoke
        • A smoke particle, dust particle, or human hair could render drive unusable
        • Clearance between head and platter is approximately two-millionths of an inch
    Image: © Shelly Cashman Vermaat 2004
  • Hard Disk Capacity Image: © Shelly Cashman Vermaat 2004
    • Hard Drive Capacity Explained
    • If 1 GB = 1,073,741,824 (2^30), then
    • 46,102,659,072 bytes / 1,073,741,824 = 42.9 GB
  • Disks
    • What are tracks and sectors ?
        • Formatting prepares disk for use and marks bad sectors as unusable
    Image: © Shelly Cashman Vermaat 2004 Track is narrow recording band that forms full circle on disk
      • Sector stores up to 512 bytes of data
  • Disk Defragmenter
      • Reorganizes files and unused space on hard disk so programs run faster
    Image: © Shelly Cashman Vermaat 2004 file before defragmenting fragmented disk file after defragmenting
  • Hard Drives
    • RPM- Revolutions Per Minute
      • Examples: 7200 RPM, 5400 RPM, 4200 RPM
        • 10,000 RPM
    • Desktop hard drives usually faster RPM than laptop
  • Solid State Hard Drive
    • Data storage device that uses solid-state memory to store data
    • Emulates a hard disk drive
    • No moving parts, therefore less fragile and quieter
    • Solid State Drive - Wikipedia Link
    • Laptops
    • More $$$
  • Other Storage Devices?
    • CD / DVD
      • Optical drives
        • Laser light burns pits onto surface
        • Change in height) land to pit, pit to land) =1, land=0
        • Single track that spirals into the center
      • CD - 650 MB to 1 GB
      • DVD - 4.7 GB to 17 GB
    • Flash Drives
      • Flash Memory Data Storage Device
      • 64 MB to 64 GB
      • Connect thru USB port
    Image from www.haimei.com Image from www.digitalswirl.com
  • Flash Memory
    • Erasable, programmable ROM
    • EEPROM
    • Used for storage devices:
      • Digital cameras
      • Home video game consoles
    • Memory Stick, SmartMedia, CompactFlash
    • BIOS Chip
    • Howstuffworks.com link
  • Processing…
    • Fastest  Faster  Fast
  • Applications
    • Today’s applications are LARGE in size
    • Not practical to place all of an application in memory while processing
      • Multitasking
    • So – what is the solution???
  • Virtual Memory
    • Virtual Memory – using a portion of free hard drive space as memory.
    • Large enough to hold programs and data for all currently running applications
    • Use main memory as cache for files
      • Just as cache memory, itself, is temporary storage for CPU.
    • Pages – blocks of hard drive space used for programs and data
  • Virtual Memory
    • Virtual memory contains entire program and data for an application as it runs
    • RAM contains sections of the program and data recently used
    • Cache contains the most recent materials used in processing by the CPU
    • Programs and data moved on an ‘as-needed’ basis
  • Application Execution Progression…
    • Hard Drive
    • Virtual Memory on hard drive
    • RAM
    • Cache
    • CPU/registers
  • Virtual Memory Step 1. The operating system transfers the least recently used data and program instructions to disk because memory is needed for other functions. Step 2. The operating system transfers data and program instructions from disk to memory when they are needed.
      • Portion of free hard drive space that is used as RAM
    Image: © Shelly Cashman Vermaat 2004
  • How Much Memory??
    • Depends …
    • Enough to run desired programs and plan for the future
    • Applications increase in size with each new version that is released!
    • I would recommend at least :
    • 2 GB – 4 GB RAM to start
    • - more if you can afford it!
  • Thrashing
    • Constant movement of materials between disk and main memory
    • Why?? Memory too small
    • Solution: Increase RAM
  • Terms – Storage
    • Boot (Warm/Cold)
    • Disk Defragmentation
    • Flash Memory
    • Hard Disk
    • Page
    • Permanent Storage (secondary)
    • Platter
    • RAM (temporary)
    • Read/Write Head
    • ROM
    • RPM
    • Sector
    • Storage devices
      • Hard Drive, Solid State Drive, CD, DVD, Flash, etc.
    • Track
    • Thrashing
    • Virtual memory
  • HOW DOES THE INTERNET WORK? Spring 2010
  • What is the Internet?
    • The Internet involves millions of computers, connected in complex ways to a maze of local and regional networks
    • Network of Networks
    • Capital “I” in Internet
  • Origins of the Internet
    • 1969
    • Department of Defense established experimental network connecting 4 research computers
    • Called ARPANET
    • 1980s National Science Foundation involved
      • Only scientific, research and academic institutions (no commercial traffic)
  • Other Developments…
    • 1989 - E-mail connectivity thru CompuServe and MCI Mail (restrictions lifted)
    • 1991 – move towards private sector
      • Network Access Points (NAPs)
      • Now called Internet Exchange Points (IXPs)
    • Internet Service Providers (ISPs)
      • Companies that connect users to Internet
        • Verizon, AT&T, Comcast, AOL, NetZero, etc.
    • Communication coordinated through national and international organizations (standards)
  • Connect to Internet
    • Ways to connect
      • Dial-up
      • Broadband
        • DSL (Digital Subscriber Service)
        • Cable Modem
        • Fiber-Optic Internet (Verizon)
        • Satellite (via a dish)
    • ISP – Internet Service Provider
      • Find one at www.thelist.com
      • Individual users enter ISP through a POP (point of presence)
        • Access Point to Internet
        • Physical location that houses servers, routers, switches, etc.
        • Bank of modems
      • ISPs maintain multiple POPs for geographic area they serve
  • Who Owns the Internet?
    • No one company or country can be considered as owner of Internet
      • Ownership shared among various entities
    • Coordination:
      • Internet Society (ISOC)
      • Internet Engineering Task Force (IETF)
      • Internet Architecture Board (IAB)
      • World Wide Web Consortium (W3C)
    • In the US –
      • ICANN – Internet names and port numbers
  • ICANN
  • Difference Between Internet and Web?
    • World Wide Web is just one of the services deployed on the Internet
      • Subnetwork
      • Linked documents, use of HTML
      • Early 1990s – First browser (graphics with text)
        • Mosaic -> Netscape
    • Other services deployed on the Internet include:
      • E-mail, FTP, IM, P2P, Telnet, etc.
  • What is Internet2?
  • Internet Address
  • Find a Web Page?
  • IP Address
  • Computers
    • Static IP address
      • Specified manually and entered into network tables
      • Permanent address
      • Mostly for file servers
    • Dynamic IP address
      • Dynamic Host Configuration Protocol (DHCP)
      • Ask network for an IP address when you turn it on (from a pool of available addresses)
        • IP address changes each time computer is used
        • Mostly for Clients (users)
          • My IP address at home 71.181.178.???
  • Web Browsers
    • Internet Explorer, Mozilla FireFox, Netscape Navigator, Opera, Apple Safari
    • System of communicating Web documents
      • Hypertext Transfer Protocol (HTTP)
        • Protocol used to transfer Web pages
    • Formatting instructions called:
      • HTML (Hypertext Markup Language )
  • HTML Tags
    • <html> </html> Begin/End of document
    • <b> </b> Bold
    • <p> </p> Paragraph
    • <title> </title> Title – top of window
    • <table> </table> Use in tabular form
    • <ol> </ol> Ordered List
    • <br> Break (new line)
    • <img src=“mypicture.gif”> Image
  • JavaScript – for Interactivity
    • Allows for local processing (on your machine) instead of on server ( server-side processing )
    • Browser handles some processing chores before transmitting to server
    • Client-Side Processing
      • Buttons, Check boxes, drop-down lists
      • Error-checking
    • Advantage
      • Faster response to user interaction
    • Disadvantage
      • Opens user to possible risks (exploit weakness in browser)
  • JavaScript Example <html> <head> <script type=&quot;text/javascript&quot;> function show_confirm() { var r=confirm(&quot;Press a button&quot;); if (r==true) { document.write(&quot;You pressed OK!&quot;); } else { document.write(&quot;You pressed Cancel!&quot;); } } </script> </head> <body> <input type=&quot;button&quot; onclick=&quot;show_confirm()&quot; value=&quot;Show a confirm box&quot; /> </body> </html>
  • Terms – Internet
      • ABILENE (Internet2)
      • ARPANET (Dept of Defense)
      • Cable-modem
      • Client-side processing
      • Dial-up
      • DSL
      • Domain name
      • DHCP
      • Domain Name Server
      • Dynamic IP address
      • Fiber-Optic
      • HTML
      • HTTP
      • ICANN (2009)
      • ISP
      • IP Number / IP Address
      • Internet2
      • JavaScript
      • MAC address
      • MAGPI
      • Mosaic / Netscape
      • National Science Foundation
      • POP
      • Satellite
      • Server-side processing
      • Static IP address
      • Top-level domain
      • WEB BROWSER
      • World Wide Web Consortium