Internet Class -- background info (updated 11/10/02)

What do people use the net for?
access to info -- library catalogs, govt docs/records, IRS
		alternative to papers, radio, TV, books, magazines
sharing data -- scholarly collaboration, political activism
accessing remote computers -- downloading software, shareware
exchanging messages -- email, forums, chat groups
effective communication -- phone tag, long distance costs
What is a network?
communication among 2 or more computers
	sharing printers 
	how computers are wired for networks
	corporate nets, ATMs, credit cards, phone system 
What does it mean to be online?
use a computer to hook into a network
What is the Internet?
	informal collection of networks worldwide
	DOD, ARPAnet, NSF, supercomputers
What are Internet service providers?
	companies that provide access to the Internet
	Cruzio, AOL, phone companies, 
What does it cost?
	$16-25/month unlimited hours
What is a modem? -- allows you to use a phone line to connect to a computer
	Macintosh @ Srnet->modem->phone system->modem @ Cruzio->computer
	baud rates, busy signals, brands, prices, fax
What are bits and bytes?
bit is switch (on = 1, off = 0)
8 bits = 1 byte
1 byte can represent all characters (letters, punctuation, etc.)
56Kbps modem can only achieve 44,000Kbps
44kbps = 44,000 bits/sec = 5500 bytes/sec (k = 1,000)
page = apprx 2500 (50x50) chars (bytes)
.5 second to send a page
screen = 640 x 480 bits = 307,200 bits (pixels)
7 seconds to send screen (picture)
Protocols -- standards for interoperability among computers
	e.g., Netscape operates the same on Macs, PCs, Unix
TCP/IP -- basic piece of the net, but transparent to user
	TCP/IP creates, sends, receives, and verifies packets
PPP -- makes home computer look like computer on service provider network
		PPP acct from Internet Service Provider (ISP) 
		PPP software from ISP, Apple, Netscape
Telnet -- net access to remote computers
Why is working at Louden different than at home?
	using direct connection (DSL) not a modem
	512k bits/sec, not 56kbits/sec
	always connected
	just like the business world