Relevant Computer Info

The Computer Consists of: Hardware –The CPU and motherboard (and bus) –Storage Devices (hard disk, memory, …) –Input Devices (keyboard, mouse, …) –Output Devices (monitor, printer, …) Software –Operating System (integrates and controls the HW while providing a user interface) –Application Software

How Computers Handle Data They work with 1’s and 0’s (binary digit or bit) A byte is 8 bits grouped together. A byte can represent a character (letter, #,..) –e.g. The letter A is A Kilobyte is (Kb) is 1024 bytes A Megabyte (MB) is 1024 Kilobytes A Gigabyte (GB) is 1024 Megabytes

Files Text file –Contain ASCII text (see Fig. 1.1 for table) –ASCII = American Standard Code for Information Interchange; a set of 128 characters Binary file –Contains data or program instructions in a computer-readable format that is unreadable to humans. Files can be compressed to make them smaller

Computer Can Communicate Means on Communication –Modems –Wireless –Network Interface Card (NIC) Network –Where 2 or more computers share information and resources –LAN (Local Area Networks): < 1 mile –Internet Software

The Internet A global system of networked computers connecting users and data. Growing quickly (33K new users/day) As of 8/96 – 72,600,000 users globally As of 3/97 – 177 countries on the net Every 3 months, the number of Web sites doubles Internet History (p. 37)

How the Internet Works TCP/IP (Transmission Control Protocol/ Internet Protocol) determines how computers connect, send, and receive information TCP/IP allows a variety of types of computers to communicate TCP converts a message into packets IP addresses and routes packets from the sender machine to the destination machine using.. –A dynamic route is selected at the time of transmission based on current network conditions.

The Internet & Addresses Each computer needs a unique ID Domain Name Service (DNS) address is people-friendly as in: cnn.com or eas.asu.edu IP addresses are computer-friendly (numerical) as in: –4 bytes (each byte is # 0-255) separated by.’s –Assigned by Network Information Center* –Can be permanent or temporary (like when you dial-up to ASU with your modem)

DNS Addresses Decomposed Each DNS address consists of a host name followed by a domain name Each domain name has the institutional site name and the top-level domain name. DNS address Host Name Domain Name eas.asu.edu eas asu.edu nsl.yahoo.com nsl yahoo.com Domain Name Inst. Site Name TLD Name asu.edu asu edu yahoo.com yahoo com