Computers Merit Badge Christopher Strauss Frontier Trails District Troop 132
ComputersMerit Badge
Christopher Strauss
Frontier Trails District
Troop 132
Computers Merit Badge Webs
Course web for this class Computers Merit Badge Course Web
Computers Merit Badge Requirements Computers Merit Badge Proof of Completion Instructor's Course Outline Computers Merit Badge Take-home Worksheet
Resource Webs (listed on the Course Web) Many other web resources are available –
just search on computers or some other term in your favorite web search engine
History of Computers - Abacus
The first true calculating machine (before 400 BC) was the abacus
Napier’s Bones (circa 1617) The Scottish inventor
of logarithms went on to construct calculating rods (made from bone) that perform multiplication and division by simply adding and subtracting
Led to slide rules (1621 – Fr. Oughtred)
Charles Babbage’s “Difference Machine” and “Analytical Engine”
1822 and 1833 designs Prototype for modern
computers Four parts: Input device,
memory (store), processor (mill), and an output device
The difference machine was actually built recently at MIT.. and worked!!
Herman Hollerith’s Punch Cards
Developed to win a contest by the Census Bureau to improve census data processing after the 1880 census had taken seven years to tabulate. They were used successfully in the 1890 U. S. Census
The concept was not THAT new – in France in 1801, Joseph-Marie Jacquard invented an automatic loom using punched cards for the control of the patterns in the fabrics.
Herman Hollerith later formed the company that became IBM (International Business Machines Corporation).
Colossus Mark I (England), Harvard Mark I, ENIAC, EDVAC
World War II: computers were developed to break German and Japanese message codes and create firing tables
Technologies: central processors were made up of vacuum tubes
Beginning with the Harvard Mark I, they could be re-programmed by re-wiring with plugs like a switchboard, or with paper punch tape
De-bugging computers is born
9 September 1945 –Ensign Grace Murray Hopper (RADM, USN) removed the first “bug” from a electromagnetic relay in the Harvard Mark II where it had been smashed, halting the computer. She taped the moth to a page the log book.
Technological Breakthroughs
1947 - William Shockley, John Bardeen, and Walter Brattain invent the "transfer resistance" device, later to be known as the “transistor,” to replace vacuum tubes
1951 – Magnetic-core memory also replaces tubes, making real-time memory use practical
Remington Rand UNIVAC – 1951 - Delivered to the Census Bureau
First mass-produced computer (46 made)
The size of a one-car garage (14’ x 8’ x 8.5’)
5,200 vacuum tubes required a chilled water air conditioning system
Government, GE, insurance companies, DuPont (scientific)
1956 Concordance of the Bible (6 mos. vs. 30 yrs)
Integrated Circuit
1958 – Jack Kilby created the first “integrated circuit” at Texas Instruments to prove that resistors and capacitors could exist on the same piece of semiconductor material. His circuit consisted of a sliver of poisonous germanium with five components linked by wires. Germanium was soon replaced by silicon (1961).
Microprocessors
1971 - Federico Faggin, Ted Hoff, and others at Intel designed the 4004 microprocessor while building a custom chip for Busicom, a Japanese calculator maker. The 4004 had 2,250 transistors, handling data in four-bit chunks, and could perform 60,000 operations per second.
Electronic Hobby Computers evolve into Personal Computers!!
1975 - Electronics hobbyists buy the earliest personal computer MITS Altair 8800 (Intel 8080)
1976 - Consumer computers arrive after several companies begin large scale manufacturing 1976 - Apple Computer Apple II 1977 - Radio Shack TRS-80 Commodore PET Heath H8, H9 1981 – IBM PC
Types of Computers
Categories Special purpose (digital watch, emission control
computer, home security system) General purpose (Mainframes, Minis, PCs)
Sizes Supercomputers (beginning with the CRAY I in
1976!! - massively parallel processing) Mainframes (multi-user IBM, DEC, NCR, etc.) Minicomputers (multi-user DEC, Sun, file servers) Microcomputers (single-user personal computers) NEW – wearable computers now in development
Uses for Computers
For supercomputers… Weather forecasting, satellite tracking, research
For mainframe computers… Banking, library automation, flight scheduling, census
For minicomputers… Operate manufacturing plants, track orders and inventory,
multi-user applications, web, email, and database services
For microcomputers… Spreadsheets, word processing, graphics, games,
communications
Parts of a Computer Central Processing Unit (CPU) is the “brain,”
and is some brand of microprocessor chip Intel 4004 – 2,250 transistors; 8088 – 40,000; 80486 – 1
million; Pentium – 7 million; Pentium II – 30 million The CPU is normally mounted in a plug-in socket on
the motherboard, a circuit board tying everything in the computer together via an electronic “bus”
Co-processors are used to offload computing tasks from the CPU, such as mathematics and graphics
Random Access Memory (RAM) and Read-Only Memory (ROM) are also mounted here ROM is permanent, often re-writable (CMOS) RAM is transient unless permanently powered (Palm)
See PC Tech Guide for more details
Schematic Diagrams What's in that Box web Click-n-learn Guide to PC PC Tech Guide Dave's Guide
Input Devices (digitizers)
Keyboard (QUERTY, Dvorak, custom – an alphanumeric symbol digitizer)
Mouse and other Pointing devices Trackball, joystick, pressure-sensitive tablet,
touch screen – a location digitizer Sound digitizer (microphone, MIDI device) Scanner (an image digitizer) Sensor (temperature, light, moisture, smoke,
movement, or other environmental digitizer)
Magnetic Storage Sequential Access
Magnetic Tape Reel-to-reel or cassette Original microcomputer media,
now used for backups Random Access
Floppy Disk (8”, 5 ¼”, 3.25”, etc.) Magnetic powder coating on flexible disk in sleeve Drive contains an actuator and read-write head on arm
Hard Disk Magnetically coated metallic platters on high-speed spindle Drive actuator with many floating read-write heads on arms
For more information see How Hard Drives Work andPC Tech Guide (where this diagram came from ----- >)
OpticalStorage
CD-ROM (Compact-Disc Read-Only Memory) Write laser burns pits into the surface of the disk Read laser bounces light off the pitted surface WORM – Write Once Read Many, or CD-R Newest formats: CD-RW, DVD, DVD-RW
Capacity (newer media have higher capacities) Compare the CD-ROM surface (left) to the DVD surface (right) For more information see How CDs Work and PC Tech Guide
Medium Typical Capacity Equivalent Size
High-density disk 1.4 megabytes 720 typed pages
Hard Drive 80 megabytes 40,000 pages
CD-ROM 540 megabytes 270,000 pages
DVD-5 4.5 gigabytes Motion picture
Output Devices Printers (the first output device) and Plotters
Impact (daisywheel) and dot-matrix Thermal (early BW and color) Laser (highest quality, BW and color) Plotters (pens on moving arms like seismographs) Ink-jet (color plotters lead to printers, some also thermal)
Monitor Analog: CRT (cathode-ray tube) – the “monitor” Digital: LCD (liquid-crystal display) screens
Sound Card (digital to analog converter) Modem (modulator-demodulator; another digital to
analog signal converter)
Computer Software
Three main categories of programs Operating Systems
Control all of the computer’s basic operations Input, output, file, memory, and task management Text-based (UNIX, CP/M, MS-DOS) and graphical (GUI) (Xerox
Star, Macintosh, X-Windows, Microsoft Windows)
Application Programs
Perform specific jobs or tasks with the computer Database manager, spreadsheet, word processor, page layout,
graphics, CAD, animation, sound, communications
Programming Languages
A program used to develop and write other programs and applications
Programming Languages
Machine code (low-level code, object code) Specific to the microprocessor (Z80, 6502, 8088) An instruction set to move decimal data through the CPU Assembly language is a mnemonic symbol set for the CPU
High-level languages Source code
COBOL, FORTRAN, BASIC, Pascal, Ada, C, VB Object oriented (modular) languages – C++, Java
Translated by a compiler into object code before run-time …or translated by an interpreter into object code at run-
time (MUCH slower – Basic, scripting languages like Perl, JavaScript, VBScript, HTML, XML)
Programming Language Use COBOL (COmmon Business Oriented Language) for business
data processing FORTRAN (FORmula TRANslator) for scientific and engineering
problems BASIC (Beginner’s All-Purpose Symbolic instruction Code) for
educational and personal computing (NOTE: Visual Basic is now widely used in business office automation to build client-server applications and integrate them with office applications)
Pascal for educational and general-purpose (led to Ada, now widely used in government and defense contracts)
C, C++ and Java for cross-platform portable, object oriented (reusable modules) application and game development
Perl, JavaScript, VBScript, and MANY other scripting languages, all interpreted, for system administration, web pages, data work
Data Storage: Text & Numbers Computers use binary numbers (1’s and 0’s) to store data. One
digit is a bit; four are a nibble, eight are a byte. Integers (whole numbers) can be stored directly in binary bytes. 0 = 00000000 3 = 00000011 1 = 00000001 4 = 00000100 2 = 00000010 5 = 00000101
A byte can be translated into a decimal number by adding up the decimal values indicated by “1’s” in the binary number 128 64 32 16 8 4 2 1 decimal values 0 0 0 0 0 0 0 0 binary places (8-bit) 0 0 1 0 1 0 1 0 binary equals 42 decimal (32+8+2)
Additional translation schemes have been developed to match character sets to decimal and binary, such as ASCII & EBCDIC
Data Storage: Text & Numbers
Text and numeric characters are stored as ASCII (American Standard Code for Information Interchange ) values, consisting of 128 different decimal codes. Extended ASCII goes to 256 codes.
ASCII translates each letter and number into a binary byte (8 bits) that the computer understands.
"1" is ASCII decimal “49” and binary 00110001 "A" is ASCII decimal “65” and binary 01000001 “&” is ASCII decimal “38” and binary 00100110 “z” is ASCII decimal “122” and binary 01111010
ASCII Translation
ASCII Decimal ASCII Binary Alphanumeric
2 1000010 B
18 1001111 O
26 1011001 Y
20 1010011 S
3 1000011 C
18 1001111 O
22 1010101 U
21 1010100 T
20 1010011 S
Data Storage: Pictures Computer pictures are stored as millions of colored dots
called “pixels” (picture elements) that have to be translated to an analog signal for an analog CRT monitor to display them (LCD panels are already digital so no translation is required).
Each black & white pixel is either on or off; each color pixel is three dots, Red, Green, and Blue (RGB) that combine to create a color. Color pixel combinations range from 256 possible colors to over 16.8 million colors (real, or true color).
The more pixels a picture has, the better it looks (it has a higher resolution). Each pixel has an associated color and location on the screen expressed in binary terms.
When stored, each pixel’s information is saved to disk separately. In a true color (32 bit) pixel, 4 bytes are used to store the color information for each dot in the pixel. For a 1600x1200-pixel display this is 8-million bytes of video memory, stored as one 8mb disk file! (bit-depth in How Computer Monitors Work) For more detailed information see How Graphics Cards Work
A pixel
Color Displays
Red Green Blue
Purple Yellow
Color Displays
Black White
Intensity - Millions of colors
Red=
Blue=
Green= 255
255
255 128
128
128 10
168
64
CRT DisplayLCD Display
CRT Dot Trio Aperture Grill Slotted Mask Enhanced Dot Pitch
LCD
Data Storage: Sound Normal sound is made up of waves or vibrations.
Each sound wave has a wavelength (how far between the waves) and amplitude (how high the wave is).
A mixed, analog waveform signal comes in to the sound card from a source (microphone) and is processed in real-time by an analog-to-digital converter (ADC) circuit chip to create a binary (digital) output of 1s and 0s. This is done at a specified interval or “sampling frequency” (i.e., 1/10th of a second).
The digital output from the ADC is further processed and compressed by the digital sound processor (DSP), and the output from the DSP is sent to the computer's CPU via the sound card connections and the data bus on the motherboard.
Digital sound data is processed by the CPU and sent to the hard-disk controller to be recorded on the hard-disk drive as a wav file.
Playback is a reversal of this process, using a a digital-to-analog converter (DAC) circuit chip to play back the binary sound file. For more detailed information see How Sound Cards Work
Storing Sound Sound waves are sampled at a constant rate (sample rate) Amplitude (height) of the wave is stored. The higher the sample rate the better the sound The higher the sample rate the more data is stored
Wavelength
ampl
itud
e
sample rate
Analog to Digital
CD Audio DVD Audio
Sampling Rate 44.1 kHz 192 kHz
Samples per second 44,100 192,000
Sampling Accuracy 16-bit 24-bit
Number of possible Output Levels
65,536 16,777,216
Communications Computers communicate if they are electronically connected,
have the appropriate software, and have common protocols or rules for negotiating their communication. Computers are digital, as are networks, but phones and wireless
communications move data primarily as analog sound waves. Modems translate digital information to analog sound for
transmission along telephone lines, and back to digital at the other end. They must synchronize speeds, block sizes, and correct errors during communications. Early modems were 300 baud (bits per second, or about 36
characters per second) 33.6 KBPS modems move over 4000 bytes per second.
Analog telephone lines are generally limited to modem speeds of 33.6 KBPS; new 56K modems and 64K to 128K ISDN connections make use some of the digital aspects of modern telephone lines.
DSL uses high frequency compression to achieve 1.5 mbps down; Cable Modems can deliver 30-40 mbps of _shared_ bandwidth
Networking Many computers make digital connections to a local area
network (LAN) or wide area network (WAN) via telephone lines (twisted pair), coaxial cable, fiber optic cables, radio, or wireless communications. Networks make it possible for large numbers of computers to
communicate with each other, and to share resources such as files, applications, and devices.
Networks manage digital traffic by moving data as packets, with elaborate protocols for ordering or prioritizing them, checking errors, and filtering.
Local area networks can be configured as star networks, bus networks, or token-ring networks
Networks can be connected to WANs or to the Internet via modem, ISDN, cable modem, satellite, and other devices
For more detailed information see How Ethernet Works
Network Configurations
Bus Network connected to a Star Network
Electronic Mail (Email) Email allows users to send and receive electronic messages
over any type of network or modem connection using a store and forward methodology. Messages are uploaded to the local mail server, passed to the
recipient’s account on that server, or forwarded to an external mail server over a number of “hops” via intermediate servers.
Messages are downloaded by the recipient’s mail client from their mail server when the messages arrive, or when the recipient opens an active connection to that server from their client.
Depending on the type of mail service, messages may remain on the host mail server or be downloaded to the local computer.
Improved bandwidth for networks and the Internet has made instant messaging and real-time chat a viable form of electronic communication, and is making voice-over-IP practical as well.
For more detailed information see How Email Works
SMTPConnections
SMTPConnections
SMTPConnections
SMTPConnections
Web Mail Server(HotMail, Yahoo,
AOL, etc.)
POP3 Server(your ISP)
IMAP Server(UNT EagleMail)
Proprietary data-based Mail Server(Exchange, GroupWise)
EmailClient
(Outlook)
WebBrowser
(IE orNetscape)
IMAP Client(Outlook Express)
POP3 Client(Netscape, OE)
* Proprietary servers usually store email messages and attachments in a real database of some form
* POP, IMAP, and some Web Email servers store email messages and text-encoded attachments as text files in most cases
* Email moves between
servers over SMTP
* The user reads their email by using some sort of client software to connect to the mail server
Computers at Work The computer industry is HUGE with many
opportunities in sales, development, manufacturing, training, implementation, support, and consulting Electrical engineers, electronics technicians, repairmen Application designers, developers, support staff, instructors,
consultants, technical writers, and editors Graphics designers, special effects, art and film technicians,
medical technicians, geosystems analysts, and any other job where the individual primarily processes computer-based information
System administrators, network administrators, database administrators, security analysts, communications specialists, and outsourcing service providers
Jobs related to the use of robotics in manufacturing
Copyrights & Software Piracy Software publishers have always taken pains to protect their
intellectual property. Most software is covered by copyright, meaning that it cannot be
copied without special permission from the author Often there will be a specific statement that you can make a backup
Most commercial software packages have elaborate licensing agreements, much more like leasing than buying
Shareware, freeware, banner ware, ad ware, and open-source software are all variations on the licensing of software
Public-domain software is not copyrighted, and is free to be copied and used
Copying software outside the limits of the licensing agreement is a crime; the Software Publishers Association (now called SIIA) has an extensive anti-piracy program and web site.