1. Unix is important because any Unix computer can connect with any other Unix 
computer. 

2. Unix is a multiuser, multitasking, timesharing system.

3. The main computer that contains the CPU and memory and storage modules is 
called the HOST.

4. To work with Unix, you use a TERMINAL.
	¥ display screen
	¥ keyboard
	¥ possibly a mouse

5. Host-Terminal Relationship (See Table 1).  When connecting by 
Telephone, a modem is used at each end, permitting PCs and
Macintoshes to emulate a terminal (character or graphical).  

6. Pressing a key on the keyboard sends a signal to the host.
       ---> The host sends a signal back to the terminal
       ---> The terminal displays (echoes) what you typed
       ---> The position on screen where the next key will show is
            marked by a cursor, usually a blinking _ or box.

7. A Terminal Server is a special computer that acts as a switch
    to other computers.  (See following Page)

8. A Network refers to two or more computers connected
    together.  When computers are directly connected by cable, 
    this becomes a local area network (LAN), Otherwise it is
    called a wide area network (WAN)  (See next following Page)

9. Major Wide area networks are connected to form part of the 
    World-Wide Internet (Network of Networks)

10. Table of Host Connectivity Methods:  (Terminal Emulation is
	achieved on other computers or other hosts via Software.)  
	Destination in all cases is to the Host.

	Source				Protocol
	------			 	--------
	Terminal                        Wireless Modem:
                                          or
	Terminal			Telephone and Modem 
                                          and: 
	Terminal Emulation		TCP/IP (via SLIP or PPP)  or
	 (e.g. Telnet, Terminal)	Novell (via Cable Connection)  or
					TCP/IP (via Cable Connection)
	
	X-Terminal			X-Window System
	
	Console				Direct Connection

11. Terminal Servers. This is a special Computer Host that permits
	connection from a Terminal to any of the Hosts on the network.  
	It acts as a software switchbox.  It can be found on
	local area networks (LANs).


12. Campus Network Backbone Connections. This refers a variety
	of Local area networks all connected to the Campus Backbone 
	(Usually High Speed Transmission line).  It looks like:

	 LAN			  LAN			Telephone Line
	  |			   |			Interface (Modem Bank)
	  |			   |				|
	  |			   |				|
------------------------------------------------------------------------------
			Campus Bankbone (T1 or T3 Transmission)
------------------------------------------------------------------------------
	  |			   |				|
	  |			   |				|
	Gateway			Terminal		       LAN
	To Out-			Server		
	Side
	(Internet)

13. Discuss how you are connected to the Host Computer.

Questions? Robert Katz: rkatz@ned.highline.edu
Last Update June 17, 2003