Computer Science Basics

Questions and Answers

What is an advantage of a compact database?

Faster data modification

Increased data redundancy

Increased null values

Simpler queries (correct)

What is a benefit of a cleaner database structure?

It makes it harder to extend the database

It makes the database more prone to errors

It slows down searching and sorting

You can learn more about the relational database by looking at its schema (correct)

Why was Unicode created?

To replace ASCII

To only support English characters

To limit the range of characters

To provide a standardized way to represent text in any language (correct)

What is a characteristic of UTF-8 encoding in Unicode?

It uses variable-length encoding Signup and view all the answers

What is an advantage of narrower tables in a database?

Searching, sorting, and creating indexes can be faster Signup and view all the answers

What is a systematic error?

A consistent difference between observed and true values Signup and view all the answers

Why is Unicode necessary in today's computing environment?

To provide a standardized way to represent text in virtually any language Signup and view all the answers

What is an advantage of extending a database without impacting existing data?

It allows for flexibility and scalability Signup and view all the answers

What is the term 'bit' a contraction of?

Binary information digit Signup and view all the answers

What is the relationship between a byte and a nibble?

1 byte is equal to 2 nibbles Signup and view all the answers

Why are binary and decimal systems called positional numbering systems?

Because each position is weighted by a power of the radix Signup and view all the answers

How many bits are used to represent a double-precision number under the IEEE-754 floating-point standard?

64 bits Signup and view all the answers

What is the main purpose of a Hamming code?

To detect and correct errors Signup and view all the answers

What is the significance of Hamming distance in error detection?

It determines the minimum number of bit positions that two code words differ Signup and view all the answers

What is the purpose of normalization in a database?

To minimize data redundancy Signup and view all the answers

What is the rule for the significand in a floating-point number?

The first digit must be 1 Signup and view all the answers

Study Notes

Binary Information and Data Representation

A bit is a contraction of "Binary Information Digit" or "Binary Digit".
8 bits equal 1 byte, 2 nibbles (a nibble being a group of 4 bits), and a word is a continuous group of bytes of any size.

Positional Numbering Systems

Binary and decimal are called positional numbering systems because each position is weighted by a power of the radix (base).

IEEE-754 Floating-Point Standard

A double-precision number under the IEEE-754 floating-point standard uses 64 bits, divided into 11 bits for the exponent and 52 bits for the significand, to represent 3 parts.

Hamming Code

A Hamming code is an adaptation of the concept of parity, used in situations where random errors are likely to occur, to increase error detection and correction capabilities.
Hamming distance is the number of bit positions that two code words differ, and it is important for error detection.
The minimum Hamming distance is the smallest distance found among all pairs of code words in the code, which determines error detection and correction capabilities.

Normalization

Normalization is the process of organizing a database to reduce redundancy and improve data integrity, or the rule that the first digit of the significand must be 1.
Normalization is necessary to:
Minimize data redundancy (duplicate data)
Minimize null values
Result in a more compact database (due to less data redundancy/null values)
Minimize/avoid data modification issues
Simplify queries
Make the database structure cleaner and easier to understand
Allow for easier extension of the database without impacting existing data
Make searching, sorting, and creating indexes faster

Unicode Characters

Unicode characters require different numbers of bits depending on the encoding used, with UTF-8 being the most commonly used encoding, which uses variable-length encoding.
In UTF-8, a Unicode character can require anywhere from 8 to 32 bits.
Unicode was created to address the limitations of traditional character encoding systems like ASCII, which only supported a limited range of characters.
Unicode provides a standardized way to represent text in virtually any language, allowing for universal text processing and communication across different platforms and systems.

Systematic Error Detection

Systematic error is a consistent or proportional difference between the observed and true values of something (e.g., a miscalibrated scale consistently registers weights as higher than they actually are).