Download Introduction to Unix

Introduction to Unix
Chapter 1
Computer Hardware
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Central Processing Unit (CPU)
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The heart and brains of a computer
The device that performs all calculations and data
manipulation in a computer
Main Memory (RAM)
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The place the CPU looks for instructions and
data to process
Computer Hardware
Mass Storage (hard drive)
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Holds information not immediately needed by CPU
Holds massive amounts of data
Input/Output Devices
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keyboard, mouse, monitor, printer
Devices used to move information into and out of
the computer
Terminology - storage
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bit
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Stands for Binary Digit.
Smallest unit of storage
in a computer
A single 1 or 0
byte
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8 bits
Used to store single
characters. (Sort of)
ASCII characters
kilo–
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Thousand
kilobyte ~ 1,000 bytes
Actually = 210 bytes
(1,024)
mega–
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Million
Megabyte ~ 1,000,000
bytes.
Actually = 220 bytes
(1,048,576).
About 350 pages of text
Terminology - storage

giga–
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Billion
gigabyte ~
1,000,000,000 bytes
Actually = 230 bytes
(1,073,741,824)
About 360,000 pages of
text
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tera–
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Trillion
terabyte ~
1,000,000,000,000 bytes
Actually = 240 bytes
(1,099,511,627,776)
About 366 million pages
of text
Terminology - processing power
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Clock speed
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FLOPS
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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.
Floating point operations per second
MIPS
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Millions of instructions per second
What is an operating system?
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A computer program that
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Supports interaction between each user and the
computer system
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Allocates computer resources, such as memory or
CPU time, to other running programs
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Controls peripheral devices (disk drive, monitor, etc.)
Common operating systems
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Windows XP, Macintosh OS, & Linux
One user or many?
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Most PCs are single-user machines
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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
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Still composed of the same 4 main components,
but just made to work with many people at once
A more sophisticated OS is required
Multitasking & Timesharing
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Unix is a multitasking operating system
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Uses timesharing to accomplish this
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It can do more than one thing at a time
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
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Allow many people to use the computer simultaneously
Components of Unix
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Kernel
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Shell
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The part of Unix that interprets user commands and passes
them onto the kernel.
File System
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The master control program of the computer.
Information stored on the computer.
Can be organized into directories.
Utilities
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Unix commands
History of Unix
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Designed to be portable — can be run on different
computers
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Began in 1969 at AT&T’s Bell Labs (a.k.a. Lucent
Technologies)
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Became a multi-user, multi-tasking Operating
System
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The original Unix was freely distributed and many
different companies took it, modified it, added
features and released their own versions
Versions of Unix
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Over time, two main versions came to be the most
popular.
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BSD (Berkeley Software Distribution)
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System V (AT&T Bell Labs)
Most other versions of Unix are based on one of
these two versions.
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Solaris (Sun Microsystems)
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SCO (Santa Cruz Operation)
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HP-UX (Hewlett-Packard Unix)
Linux
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Another version of Unix
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Created by Linus Torvalds
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While a graduate student in Finland
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Based on Minix by Andrew Tannenbaum
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Distributed freely
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Made to run on virtually all computer systems
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Red Hat is the most popular commercial distribution
Logging In
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Why do it?
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Multi-user operating system
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Needs to know who you are
User name, login ID, login, ID, etc.
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Each one is unique
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System administrators set up rules for user names
Password
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Many systems have rules about acceptable passwords
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Keep it secret, keep it safe
Logging in — How to do it
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From PC labs
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Run a telnet program, such as PuTTY
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You'll find it in the programs menu
Prompted for name and password
Unix interface
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Unix operates from a command prompt
(alphaR) 1:
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Alphas use the EZ-Shell (created at UWM)
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Exit the EZ-Shell with option 62
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Various GUIs do exist for Unix
Xwindows
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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
Once you log on
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Messages
Set terminal type
Shell prompt
Changing your password
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passwd
Obtaining help
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man [command name]
Logging out
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How
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Type “exit”
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Type “logout”
Why?