1. The System Unit What is the motherboard?  Also called the system board  Main circuit board in the system unit  Contains many electronic components

2. Central Processing Unit What are the components of the central processing unit (CPU )? CPU Arithmetic/ Logic Unit (ALU) Control Unit

3. Central Processing Unit A student enters a math problem into the memory of the computer Step 1: The control unit fetches the math problem from memory Step 2: The control unit decodes the math problem and sends it to the ALU Step 3: The ALU executes the math problem Step 4: The results of the math problem are stored in memory The result in memory displays on the screen of the monitor What is a machine cycle?  Together the four operations of the CPU comprise a machine cycle

4. Central Processing Unit How is the speed of the CPU measured?  According to how many millions of instructions per second (MIPS) it can process

5. Data Representation What is the binary system? Binary Digit (bit) Electronic Charge Electronic State  A number system that has just two unique digits, 0 and 1 A single digit is called a bit (binary digit) A bit is the smallest unit of data the computer can represent By itself a bit is not very informative  The two digits represent the two off and on states

6. Data Representation What is a byte? 8-bit byte for the number 3 8-bit byte for the number 5 8-bit byte for the capital letter T  Eight bits are grouped together to form a byte  0s and 1s in each byte are used to represent individual characters such as letters of the alphabet, numbers, and punctuation

7. Data Representation  American Standard Code for Information Interchange (ASCII)

8. Memory Bytes are the basic storage unit in memory Each byte is stored at a specific location in memory called an address How are bytes stored?  Each address has a unique identifying number, like the seats on an airplane seat C22seat B22seat A22  Each address can hold only a single byte  Each address can be full or empty

9. Memory How is memory measured?  Size of memory is measured by the number of bytes available Kilobyte - 1,024 bytes Megabyte - one million bytes

10. Storage (hard disk) RAM Step 3: When you quit Word, RAM may be used to store another program or data. The program is removed from the screen and the operating system’s user interface redisplays. Step 1: When your computer is running, certain operating system files are in RAM. Shown here is the operating system’s user interface. Step 2: When you start a word processing program such as Word, the program loads into RAM from a hard disk. As you create a document, it is in RAM and displays on your screen. Step 4: When you start a spreadsheet program such as Excel, the program loads into RAM from a hard disk. As you create a spreadsheet, it is in RAM and displays on your screen. Memory How are applications transferred in and out of RAM? Step 5: When you quit Excel, RAM may be used to store another program or data. Excel is removed from your screen and the operating system’s user interface redisplays.

11. Mobile Computers  An IrDA port allows the handheld computer to communicate wirelessly with other computers or devices  Handheld computers also can rest in a cradle, so you can transfer data to your desktop computer How is data transferred from a handheld computer? IrDA port cradle

12. Goal: To function even if part of the network were disabled or destroyed Became functional in September 1969 Goal: To allow scientists at different locations to share information and work together on military and scientific projects History of the Internet How did the Internet originate? ARPANET Networking project by Pentagon’s Advanced Research Projects Agency (ARPA) p. 2.3 Next

13. History of the Internet What is a host node? Also called a host Any computer that directly connects to a network Often stores and transfers data and messages Provides network connections for other computers Four original nodes on ARPANET University of California at Los Angeles University of California at Santa Barbara University of Utah Stanford Research Institute p. 2.4 Next

14. Technology Trailblazer Tim Berners-Lee Created the World Wide Web  Director of the World Wide Web Consortium (W3C) at MIT Click to view Web Link then click Tim Berners-Lee p. 2.4 Next

15. How might data travel the Internet using a telephone line connection? Step 1 Step 2 Step 1 Step 2 Step 3 Step 1 Step 2 Step 3 Step 4 Regional ISP Step 1 Step 2 Step 3 Step 4 Step 5 Regional ISP National ISP Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Regional ISP National ISP Internet backbone Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Regional ISP Local ISP National ISP Internet backbone How the Internet Works Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Regional ISP Local ISP National ISP Internet backbone 1: You initiate an action to request data from the Internet. 2: A modem converts the digital signals from the computer into analog signals, which are understood by telephone lines. 3: Data (request) travels through telephone lines to a local ISP. 4: Data may pass through one or more routers before reaching its final destination. 5: The regional ISP uses lines, leased from a telephone company, to send data to a national ISP. 6: The national ISP routes data across the country to another national ISP. 7: Data moves from a national ISP to a local ISP and then to a destination server. 8: The server retrieves the requested data and sends it back through the Internet backbone to your computer. p. 2.7 Fig. 2-3 Next

16. How the Internet Works What is an Internet protocol (IP) address? Number that uniquely identifies each computer or device connected to the Internet Four groups of numbers, each separated by a period Number in each group is between 0 and 255 IP address199.95.72.10 first part identifies network last part identifies specific computer p. 2.8 Fig. 2-4 Next

17. How the Internet Works What is a domain name? Text version of an IP address Components are separated by periods Each domain name represents one or more IP addresses IP address199.95.72.10 Domain name www.scsite.com p. 2.8 Fig. 2-4 Next

18. How the Internet Works What is a top-level domain (TLD) abbreviation? Identifies the type of organization associated with the domain Sometimes called dot com when TLD is com p. 2.8 Fig. 2-5 Next

19. The World Wide Web What are the parts of a URL? protocoldomain namepath http://www.nationalgeographic.com/travel/index.html