I. Operating System Basics (6a)

A. User Interface – GUI – menus, buttons, scrollbars, windows, etc

B. Running Programs

1. system calls – save to disk, read file, print document, allocate RAM, etc

2. sharing information – clipboard, Windows OLE

3. multitasking – load multiple programs in memory

C. Managing files – list of contents, folders, hierarchical file system

D. Managing hardware – OS is intermediate between programs and hardware

1. processing interrupts – requests to use memory or devices

2. drivers – allow programs to use the hardware

3. networking – allows programs to work with other computers on the network

4. utility software – defragment, file compression, backups, disk management, screen saver

II. PC Operating Systems (6b)

A. Unix – oldest OS,1970s, multiuser (and multiple applications open at same time), multiprocessor, popular for servers/hosts

B. DOS – 1970s, early consumer PCs, reliable, stable, one application/user/processor, 16-bit, hardware difficult to install, command line interface

C. MacOS – mid 1980s, first true GUI, Plug and Play, networking, multitasking, data sharing, but only ran on Macintosh hardware

D. Windows 3.x – late 1980s, Microsoft’s solution to MacOS, originally just an operating environment (ran on top of DOS), unstable, no Plug and Play support

E. OS/2 Warp – late 1980s, true OS with networking, multitasking, multiuser, multiprocessor GUI, never caught on with consumers

F. Windows NT – 1993, supposed to replace DOS/Win 3.x but was too bloated to run on most PCs, repositioned as high-end server OS

G. Windows 9X – 1995, successor to DOS, 32-bit multitasking, compatible with DOS and Win 3.X software, but no real advances over other OSs, unstable

H. Linux – focus between 1995-1998, new version of UNIX, freeware, community effort

I. Windows 2000 – different versions for multiprocessor support, based on 98 and NT

J. Windows XP – home edition, IrComm – cell phone internet

K. Windows .NET – server-based OS family, specific ones for email, internet security, databases, e-commerce, etc.

L. Embedded OS – Palm OS, Windows CE, Pocket PC OS

III. Networking Basics (7a)

A. Network – a set of technologies that can be used to connect computers together

B. Uses

1. simultaneous access (read only vs. read/write) of data and programs

2. share peripheral devices (printers)

3. communication – email, tele/video conferencing

4. backup – store data on shared storage device

C. Structure

1. local area network (LAN)

a) packet – data broken into small pieces – header, payload

b) protocol – TCP/IP (Internet), IPX/SPC, NetBEUI

c) hub – connection point

d) bridge – inspects header and forwards data

e) router – inspects header and determines route

f) gateway – connects two networks and translates information

2. CAN/MAN/WAN – larger scale, more diversified

3. node – individual computer on a network

4. client/server network

5. peer-to-peer – support distributed computing (network processing power)

D. Topology

1. Bus

2. Star – uses a hub

3. Ring – computers connected to each other

4. mesh – all computers connected to all others (more reliable)

5. wireless

E. Media

1. Twisted pair – two braided wires

2. Coax – one central wire, one wire mesh

3. Fiber optic – thin strand of glass

4. wireless – radio or infrared signal

IV. Networking the Home, the Office, and the Globe

A. Modem – digital to analog, speed in bits per second (56K)

B. Half-duplex vs. Full duplex (data sent one way at a time vs. data sent in both directions at the same time)

C. ISDN (128Kbps), T1 (1.544 Mbps), T3 (44.736 Mbps)

D. DSL, ATM, Cable (ideal 27 Mbps)

E. Internet connection sharing – connect internet to home LAN

V. Internet (8a/b)

A. How it works

1. TCP/IP – protocol for internet, a set of rules to control the way data is formatted and transmitted, allows wide variety of computers to communicate

2. backbone – the foundational set of connections tying together local/regional networks

3. address schemes – IP (4 numbers 0 to 255), DNS (maps names to IP)

4. domain = ibm.com, top-level = .com/.net, subdomain = boston.ibm.com

B. Major features

1. WWW – web pages, URL – type://address/path/

2. e-mail – address is username@domain (POP, SMTP)

3. news – newsgroups (NNTP)

4. telnet – remote access to computer

5. ftp – file transfer from remote server

6. internet relay chat (IRC) – chat rooms, channels

7. P2P – file sharing, IM

C. Firewall – controlled access to networks, can use filters, application/circuit blocks, proxy servers

D. Intranets – mostly corporate spinoffs of the internet (think private internet)

E. Extranet – allowing access to an intranet over the internet through user ID/password

F. E-Commerce – main issue is security – look for https in address or for the padlock symbol in browser (encryption enables secure transmission based on secret keys)