Operating Systems and Using Linux

1
Operating Systems and Using Linux

• Topics
• Review Number Systems.
• Go over Homework 1 Solution.
• CSHC Hours of Operations.
• What is an Operating System?

2
The Number System

• Position Number System
• The same digits have different meaning depending
  on their position in the numeral.
• The value of a digit depends on the digit itself
  of its position.
• Binary, decimal, hexadecimal are all position
  number system.

3
The Number System (cont)

• Example 4410
• 101 100
• 4 4
• ------------
• 4 x 10 4 4410

4
The Number System (cont)

• Binary Decimal Hexadecimal Binary
  Decimal Hexadecimal
• 0 0 0
  1010 10 A
• 1 1 1
  1011 11 B
• 10 2 2
  1100 12 C
• 11 3 3
  1101 13 D
• 100 4 4
  1110 14 E
• 101 5 5
  1111 15 F
• 110 6 6
• 111 7 7
• 1000 8 8
• 1001 9 9

5
Converting From Hexadecimal to Decimal

• Example Convert 1A5F16 to decimal.
• 1 A 5 F
• 163 162 161 160
• 4096 256 16 1
• Recall A16 1010 and F16 1510.
• 1 x 4096 A x 256 5 x 16 F x 1
• 1 x 4096 10 x 256 5 x 16 15 x 1
• 4096 2560 80 15
• 675110

6
Converting From Decimal to Hexadeciaml

• Perform successive divisions by 16, placing the
  remainder (0-9, A-F) in each of the positions
  from right to left.
• Continue until the quotient is zero.
• Example Convert 14310 to hex.
• 143 / 16 8 rem 1510 F16
• 8 / 16 0 rem 8
• Done answer 8F16
• To Check 8 x 16 15 128 15 14310

7
Example of Equivalent Numbers

• Binary 1 0 1 0 0 0 0 1 0 1 0 0 1 1 12
• Decimal 2064710
• Hexadecimal 50A716
• Notice that the number of digits needed is
  smaller as the base increases.

8
Homwork Solution 1

• Go over homework solution 1!

9
Operating Systems and Using Linux

• Topics
• What is an Operating System?

10
Computer Science Help Desk

• CSHC (Computer Science Help Center) is staffed
  by student tutors.
• Help with homework and projects.
• Text editors and Linux questions.
• ECS 332A Hours of Operations
• Monday Thursday 12 - 8 PM
• Friday 12 4 PM

11
What is an Operating System (OS)?

• A computer program
• Performs many operations, such as
• Allows you to communicate with the computer
  (tell it what to do)
• Controls access (login) to the computer
• Keeps track of all processes currently running
• At this point, your main concern is how to
  communicate with the computer using the OS.

12
How Do I Communicate With the Computer Using the
OS?

• You communicate using the particular OSs
• user interface.
• Graphical User Interface (GUI) - Windows
• Command-driven interface - DOS, UNIX,
• Linux
• We will be using the Linux operating system,
• which is very similar to UNIX.

13
How Do I Communicate With the Computer Using the
OS? (cont)

• When you log in to the Linux system here, a user
• prompt will be displayed
• linux1 _
• where is the number of the Linux server that
  you have connected to. You may use any of the
  Linux servers.
• The number in the brackets will change as you
  work. It is
• the number of the command that you are about
  to type.
• If this prompt is not on the screen at any time,
  you are not communicating with the OS.