Information Representation

Question 1

How do we convert from decimal to binary?

Answer 1

Keep dividing the decimal number by 2 and record the remainder.
97/2=48 - 1
48/2=24 - 0
24/2=12 - 0
12/2=6 -0
6/2=3 - 0
3/2=1 - 1
1/2= 0 - 1
Thus 97 in binary is 1100001.

Question 2

Read about Octals and hexadecimal.

Question 3

What is the Unicode?

Answer 3

The international encoding standard.

Question 4

What is sampling?

Answer 4

The representation of analog data by taking samples of the wave values over small time intervals.

Question 5

What are the two primary ways that a file (a discrete unit of data) is labeled to contextualize the data?

Answer 5

1. Through the file extension.
2. For any specialized type of data, a computer system must first be created to store all of the information in binary. New file types and data contexts are continually created every day.

Question 6

Explain what a variable is.

Answer 6

A variable is a container for information. It has three important defining factors: a name, a type, and a memory location.

Question 7

What are integers?

Answer 7

An integer is a unit number (whole number).

Question 8

Name some numerical data types used in Java.

Answer 8

Byte: integer from -128 to 127 (8 bits)
Int: integer from -2,147,483,648 to 2,147,483,647 (32 bits)
Float (smallest value): 1.4E-45 to 1.4E-45 to 3.4E38 (32 bits)
Float (largest value): 3.4028235E38 (32 bits)
Double (smallest value): 4.9E-324 to 49E-324 to 1.7E308 (64 bits)
Double (largest value): 1.7976931348623157E308 (64 bits)

Question 9

Name some non-numeric data types used in Java.

Answer 9

Char (a character): letter, number or symbol (16 bits)
Boolean: represents “true or false” (1 bit)
String: a sequence of character information (varies in size)
Array: an ordered sequence of a primitive data type (varies in size)

Question 10

Why is it important to use descriptive variable names?

Answer 10

To make the code more readable.

Question 11

What is an early method to protect files in storage from corruption?

Answer 11

Checksum. It is calculated and appended to the file when it is saved. When the file is opened, the calculation is run again to see if it matches the number stored in the file.

Question 12

What is parity?

Answer 12

An early error-checking method. For every seven bits, an eighth parity bit was added for error checking. The parity bit is sent first in a group of eight bits, and its value must make the total number of ones in the byte odd.

Question 13

What is CRC?

Answer 13

Cyclic Redundancy Check. A block of data is processed through a mathematical algorithm and a result is appended to the data. CRC is a “hashing” algorithm which always returns a value of consistent lenght.

Question 14

What is TCP/IP?

Answer 14

1. TCP/IP divides data into pieces to be sent over a network into segments or datagrams. When each segment arrives at the destination computer it is checked against the checksum value; if the values don’t match, a retransmit request is sent to the source computer.
2. TCP/IP also checks for transmission errors on other levels. The recipient machine sends an ACK for each sequence number—if one of the numbers is not acknowledged after a certain period of time, the source computer will retransmit.
3. TCP/IP will also detect broken routes over the network and re-route to new ones. It is fault-tolerant.