1. Computers & Operating Systems

2. Overview What's is a computer? Units of measurement Operating systems
Unix

3. Computer Hardware Central Processing Unit (CPU) Main Memory (RAM)
The heart and brains of a computer
The device that performs all calculations and data manipulation in a computer
Main Memory (RAM)
The place the CPU looks for instructions and data to process

4. Computer Hardware Mass Storage (hard drive) Input/Output Devices
Holds information not immediately needed by CPU
Holds massive amounts of data
Input/Output Devices
keyboard, mouse, monitor, printer
Devices used to move information into and out of the computer

5. Terminology - storage bit byte kilo- mega- Stands for Binary Digit.
Smallest unit of storage in a computer
A single 1 or 0
byte
8 bits
Used to store single characters. (Sort of)
ASCII characters
kilo-
Thousand
kilobyte ~ 1,000 bytes
Actually = 210 bytes (1,024)
mega-
Million
Megabyte ~ 1,000,000 bytes.
Actually = 220 bytes (1,048,576).
About 350 pages of text

6. Terminology - storage giga- tera- Billion
gigabyte ~ 1,000,000,000 bytes
Actually = 230 bytes (1,073,741,824)
About 360,000 pages of text
tera-
Trillion
terabyte ~ 1,000,000,000,000 bytes
Actually = 240 bytes (1,099,511,627,776)
About 366 million pages of text

7. Terminology - processing power
Clock speed
The rate at which a CPU performs its basic operations
CPU’s clock speed is measured in gigahertz (GHz)
Gigahertz ~ billion hertz (billion pulses per second).
2.4 GHz CPU has a clock speed of 2,400,000,000 pulses per second.
FLOPS
Floating point operations per second
MIPS
Millions of instructions per second

8. What is an operating system?
A computer program that
Supports interaction between each user and the computer system
Allocates computer resources, such as memory or CPU time, to other running programs
Controls peripheral devices (disk drive, monitor, etc.)
Common operating systems
Windows XP, Macintosh OS, & Linux

9. One user or many? Most PCs are single-user machines
1 keyboard, 1 monitor, intended for one person
They may run an OS capable of supporting multiple users, but not the hardware
Large computer systems are designed for multiple users
Still composed of the same 4 main components, but just made to work with many people at once
A more sophisticated OS is required

10. Multitasking & Timesharing
Unix is a multitasking operating system
It can do more than one thing at a time
Uses timesharing to accomplish this
Works on one task at a time for very short amounts of time and rapidly switches between them
Unix is also a multiuser operating system
Allow many people to use the computer simultaneously

11. Components of Unix Kernel Shell File System Utilities
The master control program of the computer.
Shell
The part of Unix that interprets user commands and passes them onto the kernel.
File System
Information stored on the computer.
Can be organized into directories.
Utilities
Unix commands

12. History of Unix
Designed to be portable — can be run on different computers
Began in 1969 at AT&T’s Bell Labs (a.k.a. Lucent Technologies)
Became a multi-user, multi-tasking Operating System
The original Unix was freely distributed and many different companies took it, modified it, added features and released their own versions

13. Versions of Unix
Over time, two main versions came to be the most popular.
BSD (Berkeley Software Distribution)
System V (AT&T Bell Labs)
Most other versions of Unix are based on one of these two versions.
Solaris (Sun Microsystems)
SCO (Santa Cruz Operation)
HP-UX (Hewlett-Packard Unix)

14. Linux Another version of Unix Created by Linus Torvalds
While a graduate student in Finland
Based on Minix by Andrew Tannenbaum
Distributed freely
Made to run on virtually all computer systems
Red Hat is the most popular commercial distribution

15. Logging In Why do it? User name, login ID, login, ID, etc. Password
Multi-user operating system
Needs to know who you are
User name, login ID, login, ID, etc.
Each one is unique
System administrators set up rules for user names
Password
Many systems have rules about acceptable passwords
Keep it secret, keep it safe

16. Logging in — How to do it From PC labs
Run a telnet program, such as PuTTY
You'll find it in the programs menu
Prompted for name and password

17. Unix interface Unix operates from a command prompt
(alphaR) 1:
Alphas use the EZ-Shell (created at UWM)
Exit the EZ-Shell with option 62
Various GUIs do exist for Unix

18. Xwindows Created at MIT General protocol for running a GUI on Unix
Handles the communication between the terminal and the server (main computer)
You also need a “windows manager” to handle how the windows will look on your computer

19. Once you log on Messages Set terminal type Shell prompt
Changing your password
passwd
Obtaining help
man [command name]

20. Logging out
How
Type “exit”
Type “logout”
Why?