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Operating Systems and Using Linux. Topics Review Number Systems. Go over Homework 1 Solution. CSHC Hours of Operations. What is an Operating System?. The Number System. Position Number System The same digits have different meaning depending on their position in the numeral.
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Operating Systems and Using Linux Topics • Review Number Systems. • Go over Homework 1 Solution. • CSHC Hours of Operations. • What is an Operating System?
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.
The Number System (con’t) • Example: 4410 • 101 100 • 4 4 • ------------ • 4 x 10 + 4 = 4410
The Number System (con’t) BinaryDecimalHexadecimalBinaryDecimalHexadecimal 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
Converting From Hexadecimal to Decimal • Example: Convert 1A5F16 to decimal. • 1A5F • 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
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
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.
Homwork Solution 1 Go over homework solution 1!
Operating Systems and Using Linux Topics • What is an Operating System?
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
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.
How Do I Communicate With the Computer Using the OS? • You communicate using the particular OS’s • 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.
How Do I Communicate With the Computer Using the OS? (con’t) • When you log in to the Linux system here, a user • prompt will be displayed: • linux#[1]% _ • 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.