Windows 7 - The Missing Manual

Overall I was somewhat disappointed by the decidedly non-technical approach this book took to the Windows 7 Operating System. I would have preferred to delve more deeply into Windows 7's inner workings. Nevertheless, it was clear and straightforward read and I will definitely use it as a resource in the future.
jw

Part 1: The Windows 7 Desktop

Chapter 1: Getting Started, Desktop and Start Menu

-          Aero; “experience” index, upgrade advisor, comprehensive list of staratup software known and instructions for turning each off (http://www.sysinfo.org/startupinfo.html), start -> default programs; jumplists; run command (Win + R); iexplore, explorer, write, wmplayer, defrag, control, calc, regedit, cleanmgr, universal naming convention for a shared folder //ComputerName/foldername

Chapter 2: Explorer, Windows and the Taskbar

-          Maximize window by double clicking the title bar, drag title bar up against top of window, Alt + Space opens the control menu for a window, MDI = multiple document interface, Alt + Esc sends an active window to the back; Aero snap and shake

-          Add shirt to Alt + Tab to lock the Alt key so Tab alone moves to the next window, this is now called windows flip; Alt + Tab (don’t hold Alt) jumps between last two open windows; Flip 3D: Win + Tab; moving through windows explorer Alt + -> moves you forward through history Alt <- moves you back

-          Address bar autocomplete: type letters hit Tab to scroll through matching options

-          Bring back menu bar: Alt  or F10; Task toolbars: Details pane (bottom), Preview Pane (right), Navigation Pane (left), Menu Panel/Task tool bar (top)

-          Explorer Window shortcuts: F6/Tab cycles highlight but skips search; F4 address bar with previous address list; Alt + D highlights address bar without list; Alt + <-/Backspace previously viewed window; Alt + -> move forward to last window; Alt + Double Click opens properties; Alt + ^ opens parent window, F11 toggles full screen mode; Shift + Ctrl + N makes a new folder; Shirt + Ctrl + E reveals folder path; Ctrl + scroll magnifies or shrinks icons; letter of file or folder + Up/Down walks through icons.

-          Libraries; metadata tags (can’t add tags or ratings to BMP, PNG, AVI, or MPG files)

-          Uni-window versus multi-window Explorer -> Organize -> Folder and Search Options -> Task bar keyboard shortcut: Win + T; Shift + Click on a taskbar item opens a new window for that program; Shift + Right Click a task bar item gives window management commands; Jumplists; action center; system tray keyboard shortcut: Win + B

Chapter 3: Searching and Organizing Your Files

-          Windows index search recognizes only the beginnings of words, not embedded strings; use two dots .. to specify a range

-          Kind: calendar, appointment, meeting, communication, contact or person, doc or document, folder, link, music or song, pic or picture, program, tv, video

-          “Folder:” in under or path (e.g., “in: documents notes”)

-          Search criteria correspond to explorer column headings

-          Wildcards at the beginning and middle of search only finds filenames not words inside files (* and ?)

-          Boolean logic: () works like AND, “” for exact phrase, OR, NOT

-          Explorer Window search Win + F or F3

-          Pressing shift while dragging from one disk to another moves the folder or file; using the right button click to drag gives you a list of options upon release

-          Deleting anything from another computer, removable drive or via command prompt bypasses the Recycle Bin

-          Pressing Shift when you delete a file bypasses the Recycle Bin

-          Drag + Alt or Drag + Ctrl + Shift creates a shortcut

-          Shortcut keys work only on shortcuts on the desktop or start menu and the combo must include Ctrl + Alt + other key

-          Free Macro program: Auto Hot Key

-          Password protected ZIPs: Secure ZIP Express (no longer password protectable through Windows)

-          ISO versus UDF: UDF live file system creates a multisession disk compatible with XP and beyond (but read as a single session disk below XP)

Chapter 4: Interior Decorating Windows

-          Multiple monitor toggle shortcut: Win + P

Chapter 5: Getting Help

-          Windows remote assistance,  requires peer name resolution protocol (http://bitly/91EBbJ)

-          Can be launched if both Windows 7 machines or both on Windows Live Messenger

-          Windows Answers, Microsoft Customer Support, Microsoft TechNet, Windows Web Site

Part 2: Windows 7 Software

Chapter 6: Programs, Documents and Gadgets

-          Drag and drop doesn’t involve the clipboard, so does not erase clipboard contents

-          By pressing Ctrl as you drag, it makes a copy rather than moving the highlighted contents

-          Speech recognition in Windows 7 getting to be pretty good

-          Toggle speech recognition on/off with Ctrl + Win

-          Show numbers, mousegrid, corrections in Alternates panel, advanced speech options

-          Gadgets = sidebar items minus the sidebar. Bring gadgets to the front with Win + G

-          Exhaustive list of all file extensions (http://www.whatis.com) , every file extension in the world

-          File association changes (1) in  explorers “Open With”, (2) start with the program and assign file types to the program in Set Default Programs, (3) Set the program by file type in Default Programs -> Associate a file or protocol with a program

-          Windows programs: (http://www.download.com  http://www.tucows.com  http://www.versiontracker.com)

-         Command line Win + R type command.com = 16-bit emulator DOS box http://www.dosbox.com

-         Compatibility mode

Chapter 7: The Freebie Apps

-         Windows 7 Upgrade advisor; command.com (ping, netstat, control, ipconfig, mkdir, copy) full list at http://bit.ly/bx0xo4

-          MathML (mathematical markup language) is understood by MS Word, Excel, PPT, OpenOffice. Math input panel allows for writing math expressions. MIP.

-          Notep log files “.LOG” on first line – notepad automatically time/date stamps envery time the file is appended.

-          Snipping tools; ease of access Win + U

-          Windows Power Shell commandlets (cmdlets); Google powershell tutorial

Chapter 8: The Control Panel

-          God mode: jkontherun.com create empty folder GodMode{ED7BA470-8E54-465E-825C-99712043E01C}

-          System: Win + Break

Part 3: Windows 7 Online

Chapter 9: Hooking Up to the Internet

Chapter 10: Internet Security

-         Windows 7 security improvements: application isolation, service hardening, protect mode, address space layout randomization, network access protection, PatchGuard, Code integrity, parental controls, Microsoft security essentials (free antivirus), action center, windows firewall, internet security zones, windows defender, data execution prevention (DEP), smart screen filter, popup blocker, InPrivate browsing and filtering

-          Starting with Vista all ports arrive closed. Windows firewall with advanced security, how to guide available at: http://bit.ly/hxR0i

-         Phish tracking companies: Cyota, Internet Identity, MarkMonitor

-         InPrivate browsing: Shift + Ctrl + P

-         “Web Beacon” = 1 pixel graphic that gathers information about visitors’ browsing habits. InPrivate filtering blocks this. Must be turned on session by session. Shift + Ctrl + F

-         To get MAC (media access control) address press Win + R -> ipconfig/all

-         Parental controls: time limits, games, allow/block specific programs, family safety, filtering, activity reporting, contact management, requests

Chapter 11: Internet Explorer 8

-          Alt + D to get address bar and prepare for typing

-          Ctrl + Enter submits URL without www or .com

-          Ctrl + W close a tab

-          Close all tabs except front one: Ctrl + Alt + F4

-          Jump to a specific tab: Ctrl + #of Tab in order

-          Quick tabs: Ctrl Q

-          Compatibility view emulates IE6

-          RSS (rich site summary OR really simple syndication) http://www.reader.google.com  http://www.syndic8.com

-          Web slice (only IE8 can use them) is like an RSS feed but you don’t lose your place on the web because it sprouts from the favorites panel

-          F11 full screen browsing toggle

Chapter 12: Windows Live Mail

-          Images can serve as bugs that report back to the sender when a message has been viewed.

-          Mailing list = discussion group conducted via email

-          RSS feeds three ways to view: gadget, IE8, Windows Live Mail

-          Newsgroups (usenet) – search on groups tab on google

Chapter 13: Windows Live Services

-          Calendar, Events, Groups, Hotmail, People, Photos, SkyDrive, Spaces, Writer, Photogallery, Mail, Family Safety   http://home.live.com

Part 4: Pictures, Music and TV

Chapter 14: Windows Live Photo Gallery

-          Show video and images, syncs with Windows Live, INFERIOR TO PICASA, import, organize, tag, rate, edit, share

Chapter 15: Windows Media Player (v12)

-          Visualizations, skin, playback speed slider, autoplaylists, sharing music

-          Allmusic.com – massive DB of music

-          Format: WMA VBR maximizes quality and minimizes size

Chapter 16: Windows Media Center – transforms playback into a 10-foot away experience

Part 5: Hardware and Peripherals

Chapter 17: Print, Fax and Scan

-          Can create several icon s for same printer with different settings

Chapter 18: hardware

-          Windows upgrade advisor, device stage, device manager

Chapter 19: Laptops, Tablets and Touchscreens

-          Handwriting recognition, multitouch screen, flick versus gesture

Part 6: PC Health

Chapter 20: Maintenance and Speed Tweeks

-          Chkdsk, diskmgmt.msc

-          Speeding things up, superfetch, ready boost, shut off bells and whistles, windows update, move virtual memory to a separate drive, remove updates, resource monitor

Chapter 21: The Disk Chapter

-          Dynamic disks, disk quotas limit the usable space for each user, encrypting file service (EFS), bit locker, gpedit.msc

Chapter 22: Backups, System Restore and Troubleshooting

-          Reports, event viewer

Part 7: Networking and Homegroups

Chapter 23: Accounts and Logging On

-          Task manager: Ctrl + Shift + Esc

-          Secret administrator (w/o password) account comes to life on Windows 7 if started in Safe Mode and no real administrator account exists, “control user-passwords2”

Chapter 24: Setting up a Workgroup

Chapter 25: Network Domains

Chapter 26: Sharing Files on the Network

-          UNC Universal Naming Convention

Chapter 27: Windows by Remote Control

-          Host unattended, remote (one in use)

-          MMC (Microsoft management console)

Part 8: How Printers Work

Chapter 32: How Black-and-White Printing Works

How Printers Make Cookie Cutter Text

Bitmap or outline (postscript/truetype)

How the First Printers Created Text

How a Laser Printer Works

Write-black (Canon, HP) produce finer details versus write-white (Ricoh) which yield darker black areas.

How Color Printing Works

Thermal printer (vivid but slow); color laser printer (precise detail but expensive); dye sublimation/dye diffusion thermal transfer (D2T2); solid ink (virtually indistinguishable from color photos even at 300 dpi.

How Printed Colors are Created

Additive color (light); Subtractive color (pigment); color pixel print offset = dithering; ink drops are 1/10e6 of a drop of water

How a Color Ink Jet Printer Works

How a Photo Printer Works

Dye inks are slow to dry and fade in light but have a wide gamut. Pigments are dye based but better resist light and environmental degradation. Photo quality printers use more inks (CMYK + light red + light blue + gray or green).

Piezo electric nozzles (piezo is a crystalline substance that bends with electrical stimulation) give greater control over the size of the drops than an ink jet (small as 2 picoliters). Paper that best suits the ink is ceramic coated porous papers (absorbs ink quickly but ceramic coating leaves ink exposed); plastic coated swellable papers protectively encapsulate dye and pigment when ink seeps into fibers.

Dye sublimation printer print heads heat colored film (one each for CMYK) and sublimate color from film to paper for each color in the final product.

How a Color Laser Printer Works

Electrostatic charge, tandem color laser printer

How a Solid Ink Color Printer Works

Solid ink is melted into a reservoir in the print heads, each nozzle is piezo controlled to push ink drops onto an offset drum.

Part 7: How the Internet Works

ARPA net; interface message processor (IMP) incorporates TCP/IP; first message “L” from UCLA to SRI sent by Charlie Kline. High speed backbone built by NSF to connect 5 supercomputing centers, then agreed to share bandwidth to allow other nets to connect through the backbone. 1991 NSF lifted commercial restrictions on the internet. WWW – a section of the internet developed for graphics, sound and video rather than text. 1988 Robert Morris Jr. releases internet worm affecting 10% of the 60k hosts on the internet. 1992 Jean Armour Polly coins “surfing the net.”

Chapter 24: How Local Area Networks Work

How Packets Divvy Up Data

Carrier wave; information wave; packet equivalent to carrier signal and permits bundling, addressing, error correction, organization of data packets varies to match the type of data they contain, may be called frames, segments or blocks; header = delivery IP, sender IP, number of packets, sequence number; Payload (1-1.5K); Footer/Trailer = CRC. Each packet sent separately through the best available route, the receiving computer reassembles the payload.

How Networks are Laid Out

NOS; peer-to-peer network; dumb terminal; wide area network; virtual network; topologies: bus topology, token ring, star topology.

How Network Nodes Connect

Bayonet Neill-Concelman (BNC) coaxial cable twists in twisted pair wires cancel out electrical noise. Registered jack (RJ) as in RJ 45 or RJ ; fiber optic carries 1 Gbps; reflective cladding; Ethernet packet = preamble, destination address, source address, type, data, CRC.

How Phone and Power Lines Bring LANs Home

Phone line bandwidth = 1 Mbps; power line bandwidth = 350 Kbps; phone line networks cannot cross a PBX or connect to a different phone line in the same building; power lines make a network available throughout a building; possible for computer to control other devices on a power line network.

Chapter 25: How PCs Connect to the Internet

Terminal adaptors

How a Dial Up Modem Calls the Internet

Analog local loop (maximum 36 Kbps) to public switched telephone network (maximum 64 Kbps). ADC records pulse code modulations (maximum 33.6 kbps due to analog line noise). ISP returns data (56 Kbps) uses mu-law codec to translate data into symbols  (maximum 56.6 kbps –actually 53 due to power regulations). Analog local loop to DAC to data translation at computer.

How DSL Turbocharges a Phone Line

How Cable Modems Bring the Internet to Your PC

Chapter 26: How the Internet Moves Data

How Networks Talk with Each Other

Application layer; presentation layer; session layer; transport layer; network layer; data-link layer; physical layer.

How Information Travels the Internet

Network access point (NAP)

Chapter 27: How We Reach Each Other Through the Net

SMTP (simple mail transfer protocol), POP (post office protocol), Multipurpose Internet Mail Extensions (MIME); mail reflector

How Internet File Sharing Works

Traditional structure if internel is server concentric; more distributed structures are an alternative; true peer-to-peer is slower but difficult to police as software makes a computer a client and host at the same time.

How BitTorrent Spread the Wealth

BitTorrents sent randomly from many sources in a rarest-first scheme. Universe of peers and trackers exchanging and requesting bits is called a swarm. Tracker software slows down leeches and rewards seeders Trackerless trackers.

How Email Replaces Snail Mail

Attachments digitized using algorithms such as MIME, uuencode, BINHEX; DNS tells SMTP the best path for the message based on the domain of the addressee; routers determine pathway; gateways translate the data from one type of system to another.

How Chat Rooms Throw a Party

How Internet Messaging Lets You Pass Notes

Trillian

Chapter 28: How Wireless Sets PCs Free

How WiFi Spreads the Net Everywhere

Access point (AP) ; probe request; Institute of Electrical and Electronics Engineers (IEEE); WLAN; Routers deal with encrypted and addressed outer shell of messages and are destination points for content going to their WLAN; hot spots

How Cellphones Make a Call

System identification code (SID); control channel; mobile telephone switch office (MTSO); handoff; digital time division multiple access (TDMA); analog frequency division multiple access (FDMA); digital code division multiple access (CDMA); spread spectrum.

How Wireless Internet Keeps You Connected

Wireless application protocol (WAP); wireless markup language (WML); cards are translated to HTML at WAP gateway which extracts and encodes incoming data into byte code which is displayed in WML.

How Bluetooth Keeps Devices Connected

King Harold Bluetooth of Denmark, unifier of Scandinavia; link manager (LM); standby/sniffmode; page mode; inquiry mode; park mode; hold mode; 79 different hop frequencies.

How the iPhone Makes It All Slick

Gesture and multitouch; two types of touch sensors for screen: mutual capacitance and self capacitance.

Chapter 29: How the Net Provides Video and Audio on Demand

Streaming uses User Database Protocol (UDP) different from TCP in that UDP allows the connection to lose occasional packets.

How a PC Plays Streaming Audio

Click link to audio source -> Metafile -> Launch player -> player contacts server with connection speed -> server sends appropriate size file using UDP -> packets decompressed and decoded then sent to buffer -> when buffer is full audio file plays (and rebuffers if the buffer empties).

How a PC Displays Streaming Video

Captureboard converts analog to digital 30 fps using a codec algorithm, interframe compression, internet provider (IP) multicast – uses less bandwidth than UDP but requires a multicaster. PC receiving signals decompresses the video and split it into video and audio and these are sent to the video card and sound card respectively. Corrupted video can carry over to other frames; software compares new frames with others to detect errors and correct them.

Chapter 30: How the World Wide Web Works

How a Web Browser Opens Web Pages

Universal resource locator (URL); network solutions has the exclusive right to register domain names under agreement with NSF.

How a Web Browser Displays Pages

How Cookies Save Crumbs of Data

Cookie manager; cookie monster free program from ampsoft.net

How Google Knows Everything

Google bot crawls the web and sends full text from each page to Google’s indexing program and adds all links to its queue. Bot calculates the frequency of changes on each site and modifies the crawl rate to capture changes most effectively. Indexer stores text in a DB, each entry contains a list of pages where it appears. Google skips stop words, single digits or letters, and some punctuation marks. Index servers return a document based on relevance to a search including Page Rank where indexed terms appear if popular pages link to that page. Google’s doc servers summarize the page contents of the search results and pass them to the web servers that forward them to the searcher.

How eBay Sells Everything

Four geographically distinct mirrored data centers linked by SONET (synchronized optical network); searches are sent through search servers which send the search request to clusters of 50 db servers.

Chapter 31: How Internet Security Fights Off PC Invaders

Script kiddie.

How Computer Hackers Break Into Your PC

Hacking is methodical and incremental over the course of days or weeks; footprint analysis (publically available information); scan ports using available hacking software and map them and their relationships; a hacker uses these data to identify types of file transfer and email by sending random data to the ports often triggering a banner response that identifies the software using the port. This software is checked against online databases that list its vulnerabilities. Two ways to gain access: low tech is to trick employees into revealing their password, or use a brute force attack which uses a known username and a list of common passwords which ends either in (1) exhaustion of list, (2) lockout, or (3) access. Once access is gained, the hacker escalates privileges by looking for passwords of higher level users in the registry keys or email. Once access is achieved Trojans are uploaded to open a backdoor in the system to allow the hackers to access at will.

How Spyware Reports Everything You Do

Spyware, adware. Antivirus programs and firewalls cannot block spyware installed as a requested program so it is often bundled this way. Other spyware embeds itself in the registry where it is harder to find and more dangerous to remove. Spyware information could be stored in a cookie. Spyware opens a backchannel to send information found on your computer. Tricklers reinstall spy files as fast as they are deleted. Spybot Search and Destroy is a good spy assassin.

How Internet Firewalls Keep Out Hackers

A firewall is hardware or software; manager sets the rules to filter out unwanted intrusions, shut nonessential ports, and possibly block all inbound traffic except mail or specifically requested data. Packet filtering compares outbound addresses to a blocked list. Proxy server outside the firewall takes the hit if a dangerous transmission makes it past the filters. Stateful inspection compares key parts of each packet to a DB of known safe data, packets that fail are overwritten by subsequent packets. Firewall sends an alert and updates a security log with the type of attack, IP of orgin, and records of packets with intrusive code.

How Computer Viruses Invade Your Computer

When virus code is run it typically performs four actions: replication (boot record viruses run before the OS is loaded, program viruses insert copies of themselves following program headers); event watching (whenever a specific state exists the virus delivers its payload, without the trigger it just replicates); camouflage (nonfunctioning section of fake code that change each time it replicates or falsify header information so the program file appears to be the correct length); delivery. Memory-resident virus.

How Viruses Travel in Your Mail

Three types of mail viruses: attachment virus (must be double clicked, e.g., Loveletter, Melissa, Anna Kournikova); HTML virus (merely previewing activates the virus, e.g., Kakworm, BubbleBoy, Haptime); MIME virus (uses an OE/IE security hole and fills the email header until the buffer overflows into stack memory where the virus is executed instead of legitimate code – can run even if not seen, e.g., Nimba)

Email viruses replicate by getting names and email addresses then sending themselves out, perhaps with haphazard attachments.

How Antivirus Software Fights Back

AV software inspects master boot records, program files, macro code. Signature scanners inspect for code that matches a table of known viruses. Heuristic detectors look for time/date targeted events, routines to search for .com or .exe files and disk writes that bypass the OS. Memory-resident antivirus software install programs in RAM that operate in the background to identify behavior associated with viruses.

How Spammers Find You

Automated spiders that compile addresses from mailto: links and usenet newsgroups and chat rooms. Directory Harvest Attack sends generated email addresses to a mail server and log s any that do not produce an SMTP 550 error message.

How Antispam Software Sniffs Out Phony Email

Blacklists; junkmail filtering; content filtering; Baysian filters; whitelists; peer-to-peer shared white and black lists; spammerwocky

How Prime Numbers Protect Prime Secrets

Encryption uses two prime numbers as a private key; the product of the two primes are the public key. 128 bit encryption – no known way to factor a number larger than 80 digits. Digital signatures created by computing a message digest or hash value which is encrypted using a private key.

Part 6: Games and Multimedia

Chapter 20: How Multimedia Sound Works

How Sound Cards Work
How MIDI and FM Synthesis Work

• FM synthesis not as realistic as a MIDI wavetable

How Digital Sound Tricks Your Ear

• AC3=Dolby Digital 5.1 5 speakers + subwoofer, 6 channel sound (5 @ 3Hz-20kHz, 1 @3Hz-120Hz low frequency effects channel)

MP3 and Digital Audio Compression

• Just Noticable Difference (JND)

How 3D Audio Works

• Interaural intensity differences, interaural time difference, pinnae positional clues

How iPods Dish Out Media To Go

Chapter 21: How Multimedia Video Works
How the Digital Camcorder Captures Future Memories
How A Digital Camera Squeezes Video Down to Size

• MPEG Motion Pictures Expert Group
• Standard TV 4:3 720w x 576h, 30 fps

How TiVO Unites TVs and Computers

Chapter 22: How Game Hardware Puts You in the Action
How Video Cards Break the Game Barrier

• ATI crossfire
• NVidia GPU Scalable link interface
• Scissors rendering and supertiling
• Shaders, double anti-aliasing

How a Joystick Puts You at the Controls

• Potentiometer

Part 6: Games and Multimedia

Chapter 20: How Multimedia Sound Works

How Sound Cards Work

How MIDI and FM Synthesis Work: FM synthesis not as realistic sound production as a MIDI wave table

How Digital Sound Tricks Your Ear: AC3=Dolby Digital 5.1 – 6 channel sound (5 speakers @ 3Hz-20KHz; 1 non-directional subwoofer [low frequency effect channel] @ 3Hz-120Hz)

MP3 and Digital Audio Compression: Just Noticeable Difference (JND)

How 3D Audio Works: Interaural intensity difference, interaural time difference, pinnae positional clues

How iPods Dish Out Media to Go

Chapter 21: How Multimedia Video Works

How the Digital Camcorder Captures Future Memories

How a Digital Camera Squeezes Video Down to Size: MPEG=Motion Picture Expert Group; Standard TV, 4:3 aspect ratio, 720w x 576 h, 30 fps.

How TIVO Unites TVs and Computers

Chapter 22: How Game Hardware Puts You in the Action

How Video Cards Break the Game Barrier: ATI “CrossFire” vs. NVIDIA GPU scalable link interface; scissors rendering, supertiling, shaders, double anti-aliasing.

How a Joystick Puts You at the Controls: potentiometer

How Force Feedback Joysticks Work

How Game Controllers Put Play at Your Fingertips

Chapter 23: How Games Create 3D Worlds

How Computers Plot a 3D World: PC games pinpoint 47 billion dots per second; tessellation, redraw 15-20 times per second, z-sorting, z-buffering, hidden view

How 3D Graphics Get Dressed: texture maps, texels, MIP Mapping (multim in parum), perspective correction, alpha blending, stippling

How Shaders Control the World: shape, color, shading (value), bilinear filtering, trilinear filtering, Gouraud shading, ray tracing, vertex shading (including displacement), particle shaders (fire effect)

How Games Create New Worlds: MMORPG

Part 5: Input/Output Devices continued…

Chapter 15: How Scanners Capture Words and Images

Photodiodes were created in the 1970s.

How Computers See: 

B used for p-type Si, Ph used for n-type Si.

CMOS photodiode array has an amplifier for each diode.

How a Flatbead Scanner Works

Chapter 16: How Computers Use Power

How the Power Supply Works: emi filter scrubs power, transistors increase frequency, transformers step down voltage to 3.3/5V (CPU, DIMM, PCI, GPU, etc.) and 12V (disk drives), diodes rectify the power to DC, input and output capacitors store electricity, heat sink and fan cool hot components, power is filtered before use.

How a UPS Keeps Your Computer Going

How Surge Protectors Work: power sag, power surge, toroidal choke coil, electrical noise, shunt mode, metal-oxide varistor (MOV)

Chapter 17: How Serial Ports Triumph

Analog and Digital Converters

How Bandwidth Moves Your Data: cache data, reduced latency, prefetch data, carrier waves, modulator waves, bandwidth

How Parallel Ports Work: 2.5 Mbps transfer rate

How Serial Ports Work: 100 Kbps transfer rate

How the Universal Serial Bus Works: high speed (D+) = 12 Mbps, slower (D-) = 1.5 Mbps, USB2(?) = 480 Mbps. Data priorities: isochronous/RT (highest), interrupt transfers (second), bulk transfers (when time permits)

How Serial ATA Overtakes EIDE: EIDE was never explained?! Discussion about SCSI and SATA

Chapter 18: How a Computer Displays Works

Important concepts: Ben Day dots, Pixel = Picture Element

How a CRT Paints the Screen: surface conduction electron emitter display (SED) is called out as the front-running technology.

How an LCD Screen Works

How Plasma Displays Glow

How Digital Light Processing Works

Chapter 19: How Digital Photography Works

How Digital Cameras Capture Light

How Autofocus Lenses Work

How Auto Exposure Works

Part 5: Input/Output Devices

Distance plays a role in modern electrical devices. EM noise is also an important consideration leading to sometimes twice as many wires as necessary to transmit a signal because the extra wires are used to dampen noise. Since the 1970s Xerox PARC has been studying how people communication information.

Chapter 14: How Data Gets Into Your PC

Although the mouse never replaced the keyboard, the pointer (mouse, eraserhead, trackpad, trackball) supplements it almost universally.

Keyboard and Scan Codes

Pressing a key changes current and a microprocessor detects the change: increased when the key is pressed, decreased when it is released. The scan for changes repeats several hundred times per second, but only acts on signals that are confirmed in 2+ concurrent scans. The microprocessor generates a number called a scan code associated with the key’s circuit. Each key has two codes: one for depressed, one for released. These data are stored in the keyboard buffer and loaded into a port where they are read by BIOS which sends code to delete them from the buffer once they have been received. Two bytes track when shift or special toggle keys have been depressed, so that the code that follows can be augmented to reflect the combination of keys strokes. There are two ways to construct a keyboard: capacitance (springy, clicky keys) or hard contact (rubber dome collapses to allow contact between two metal plates).

How Mice Obey Your Every Gesture

The rolling of the mouse ball moves two rollers that are positioned at 90 degrees relative to one another to capture movement on the X and Y axis. Rollers are attached to an encoder which has a series metal contact points that records distance based on the number of contact points recorded. Signals are sent to the PC through the “tail” (cable) and the cursor moves accordingly onscreen. The click buttons send information about the button clicked and the number of clicks.

The optical mouse uses an LED or laser to light the surface on which the mouse is placed.  A small camera inside the mouse scans the surface at 100 fps and sends the results to the DSP which calculates movement based on the change in the relative position of identifiable structures.

How a Touchpad Works

How a Pointing Stick Works

How Speech Recognition Works

Part 4: Data Storage continued...

Chapter 13: How PCs Use Light to Remember Data

Magnetic recording will eventually be supplanted by optical data storage. CDs and DVDs use optical technology that yields tremendous increases in storage capacity over magnetic media due to the ability to focus a laser beam to a point smaller than a pinpoint. DVD or digital versatile discs use a two level storage system that hold 8.6 GB of data versus the 700 MB of a CDROM. This again pales in comparison to the storage capacity of Blu-Ray (23-27 GB per layer) and HD-DVD (15 GB per layer), both technologies can hold multiple layers of data. Holograms can expand the capacity of PC storage into the scale of terabytes.

How a CD-ROM Drive Works

• A motor constantly varies the spin rate of the CDROM so that the portion of the disc immediately below the detector is always spinning at the same speed (constant linear velocity). This solves the issue of angular velocity that requires magnetic media to have larger sectors on the outside of the disc than at the inside.
• The CDROM sectors are arranged in a spiral that is divided into equal-sized sectors arranged in a single track.
• The laser penetrates the plastic protective layer and reads the surface of the disc by recognizing lands (flat areas) and pits (depressions in the surface area) which record the 1s and 0s.
• Light that strikes a pit is scattered, but light that strikes a land is reflected back at the detector and through the use of a prism is directed to a light-sensing diode that generates a small voltage. By matching the voltage spikes against a timing circuit a stream of 1s and 0s are generated.

How a Recordable CD-ROM (CD-R) Works

• The disc is build from a thick substrate of polycarbonate plastic, a layer of dye (usually green), a gold layer, lacquer protective layer, and a scratch-resistant polymer layer (sometimes topped with a silk-screened label).
• The laser’s write head follows a spiral groove cut into the plastic layer called an atip (absolute timing in pregroove). The frequency of the waves varies continuously and by reading the frequency of the waves, the CD drive can calculate where the head is located in relation to the surface of the disc. The drive uses the atip information to control the speed of the motor turning the disc.
• The software uses to make a CD recording sends the data in a specific format which automatically corrects errors and creates a table of contents. The drive records information by sending a high-powered pulse of the laser beam at 780nm wavelength.
• The dye layer is designed to absorb light at that specific frequency which creates a mark in one of three ways: the dye may be bleached, the polycarbonate layer may be distorted, or the dye layer might form a bubble. The resulting distortion (stripe) along the spiral track.
• The lengths of the stripes vary as do the spaces which encodes a specially compressed data stream and error checking. The change in the dye is permanent, making it a WORM medium.

How a Double-Layer DVD Works

• The DVD is built with polycarbonate plastic, then L0 the first of two data layers, then a layer of clear plastic separates L0 from L1 which is a second layer for holding data, L1 is capped with another polycarbonate layer thicker than the first (this bottom layer gives the entire disc stability).
• Two major differences from writing and reading CD-Rs:
• The DVD drive uses a red laser with a shorter wavelength than the IR laser used with CDs to read and write discs. Shorter wavelength = narrower beam = smaller lands and pit = tighter spiral. This alone creates the difference in storage capacity 700MB versus 4.7 GB
• The second layer of reflective metal or dye doubles the capacity of a DVD to 8.5 GB. The same laser is used to write or read the second layer by changing the focal length of the  laser to pass harmlessly through L0 to strike L1.
• The potential capacity of a DVD can again be doubled by applying the same materials to the reverse side of a DVD thereby doubling the capacity to 17 GB. However, these are rare and likely to become rarer with the introduction of HD-DVD and Blu-Ray technologies.
• The spiral tracks of data recorded on a double layer DVD coil in different directions. Starting on the center of the disc the laser head follows the first spiral track to the outer edge of the disc and then continues into the second spiral moving back in toward the center. This design prevents delays in the flow of data.

How DVDs Play the Blues

• Blu-Ray and HD-DVD, two competing and incompatible designs use an ultra-thin blue laser beam but Blu-Ray holds 26GB while HD-DVD holds 15GB.
• The common DVD uses a red laser at 650nm, a small difference that allows for seven times more data storage. The coils of the tracks are 0.7 microns apart and the lands and pits are smaller. (CD is 790nm and coils are 1.6 micron apart).
• HD-DVD and Blu-Ray uses a blue-purple laser that is 405nm wide, with coils of tracks that are 0.3-0.4 microns apart (about ¼ the distance that separates common circuit traces in microprocessors)
• Blu-Ray has a thinner protective plastic coating 0.1mm thick which allows for a smaller distance between track coils (0.32 microns), and hence a greater storage capacity.
• HD-DVD uses 12:8 demodulation which converts each group of 12 optical bits into 8 data bits. It also users a thicker protective layer (0.6mm) that provides more protection but forces the drive to use wider lands and pits. The resulting distance between track coils is 0.4 microns. Together this accounts for the difference in storage capacity.

Part 4: Data Storage continued...

Chapter 11: How Disk Drives Save Information

The capacity, size and performance of disk drives have changed dramatically since their introduction as standard equipment on the first IBM XT in the 1980s.

How a Floppy Drive Stores a Little  

• ·         When a 3.5” disk is pushed into the drive levers pull back the shutter to expose the cookie
• ·         Two read/write heads move until the barely touch the cookie on either side and generate magnetic pulses to change the polarity of metallic particles in the disk’s coating, a motor spins a shaft which rotate the disk from the hub while a stepper motor positions the head.
• ·         The drive’s circuit board receives signals that control the head, if a write command is received an LED/sensor combination check to make sure the write protect tab is not open (meaning the disk is protected) before commencing the write

How a Hard Drive Stores a Lot

• ·         A sealed metal housing protects the drive from dust which could cause a crash due to tolerances less than the thickness of a human hair between the read/write heads and the disk.
• ·         Commands are received from BIOS through the disk controller which converts generic commands into ones that are specific to that drive.
• ·         A spindle spins as many as eight coated platters.
• ·         When reading or writing the OS first checks a file allocation table or master file table to determine the physical location(s) of the desired file or to find an available cluster for writing and passes this information on to the drive’s built-in disk controller which in turn instructs the head actuator on how to move the read/write arms to align the heads to the correct cluster. If writing it records the location of the file’s clusters in the FAT or MFT.
• ·         Typically there is a gap of only 2/10e6 inch between the heads and the disk surface.

How a Mirrored Drive Array Protects Files

• ·         RAID – redundant array of independent (or inexpensive) drives can speed performance and provide second-to-second protection against disk crash depending on how the array is configured.
• ·         When data integrity is more important than speed and there are only two hard drives, the best solution is a mirrored disk drive (or RAID 1). The RAID controller replaces an ordinary disk controller with software to handle arrays, writes every file to two or more drives simultaneously. In case of a read error caused by surface defect or crash, the controller reads the intact version of the file from an undamaged drive.
• ·         To read a file from a mirrored array, the controller reads alternate file clusters from each of the drives and pieces them together for delivery. This makes reads faster proportionate the the number of drives in the array (2 = 1/2, 3 = 1/3 the read time).

How Striped Drive Array Boosts Performance

• ·         For faster reads and writes a RAID is set up as a striped array (RAID 0) of two or more hard disks. The RAID controller divided files into several pieces and writes different sections to different drives at the same time. To read the controller simultaneously pulls each part of the file from the different drives on which it’s stored then pieces the parts of the file together in correct order when it writes them to RAM.
• ·         In a striped array with parity (RAID 4), the controller writes striped data to all but one of the drives which is used for error checking.  The controller’s array software performs a Boolean XOR operation on the data written to the drives and writes the result (a parity bit) to the remaining drive. An XOR operation results in a 0 bit whenever two like bits are compared and a 1 bit whenever two dissimilar bits are compared. If more than three drives are in the array, the first two are XORed and the result is XORed with the next drive, etc., until all the data drives have been XORed and the final result is written to the parity drive.  Later, if one of the files is damaged or a drive crashes, the controller can deduce whether the missing bits are 1s or 0s. This reverse XOR can also be used to repair minor media defect damage on the fly.

Chapter 12: How Little Things Make Drives Faster and Bigger

Scientific progress is incremental, most advances are made by plodding toward incremental gains rather than by momentous discoveries. Computer speed has always been limited by computer storage speed.

How Small Changes in Drives Get Big Results

• ·         The ZIP drive increased data volume and access speed over floppy storage, but allowed for portability.
• ·         A smaller head allowed 2118 tracks per inch, compared to 135 tracks per inch on a floppy disk.
• ·         Additional storage capacity came from coating the cookie with the same magnetic particles as a S-VHS video tape which have a higher energy level and therefore not as easily magnetized. So the magnetic field from the write head affects a smaller surface area.
• ·         Change from radial sectors (which waste storage space on the outer tracks) to zone recording (also used for hard drives) so that the same recording density is used throughout the disk.
• ·         Perpendicular recording

o   The superparamagnetic effect limited storage capacity because proximity caused charges to interfere with one another.

o   Iron core redesigned to ride close to the disk’s surface and force a stronger magnetic field through a smaller area leaving particles magnetized perpendicular to the path of the magnet.

How File Compression Makes Files Smaller

• ·         Makes files smaller by eliminating redundancies in the file (lossless compression)
• ·         Uses some variation of LZ (Lempel and Ziv) adaptive dictionary-based algorithm, which examines the file for recurring patterns of data which are written to a dictionary stored as part of the compressed file. The compressed file is stores as a reduced version with pointers indicating where the omitted dictionary sections can be found. Adaptive means that the algorithm constantly looks for more efficient data patterns and changes entries on the fly.
• ·         The type of file determines how much compression takes place, length is also a determinant in degree to which a file can be compressed. On average files can be compressed 50%, but some can be compressed to only 20% of their original size.
• ·         Graphics files often use lossy compression which reduces file size by discarding data such as small variations in color. These files can never be returned to their original state from the compressed version. Utility programs can further compress files, they tend to emphasize storage over speed.

How Disk Defragmentation Works

• ·         Data is written to new disks in contiguous clusters. However as files are deleted, available clusters may not be adjacent. Defragmenting reorders data so that data from a file is in a contiguous set of clusters. Defragmentation helps to speed the read and write actions by reducing the amount of time moving from track to track passing over unrelated sectors.
• ·         Defragging or disk optimization is a software operation that moves the scattered parts of files so that they are contiguous on the disk by first moving out fragmented block to make space and then moving the file data back into the contiguous cluster group. Windows Vista automatically defrags drives when they are idle.