1.1 InfoRepr&Multimedia.data_representation Flashcards
What is the binary number system?
A base-two system using only the digits 0 and 1
What is a bit?
A binary digit, the smallest unit of data in computing.
What is one’s complement?
A method of representing negative numbers by inverting all bits in a binary number.
What is two’s complement?
A method of representing negative numbers by inverting all bits and adding 1 to the right-most position.
What is sign and magnitude representation?
A binary number system where the left-most bit indicates the sign (0 = positive, 1 = negative).
What is hexadecimal?
A base-16 number system using digits 0-9 and letters A-F.
What is a memory dump?
The contents of a computer’s memory output to a screen or printer.
What is binary-coded decimal (BCD)?
A system that represents each decimal digit using 4 bits.
What is ASCII?
A character encoding system for keyboard characters and control codes.
What is a character set?
A list of characters defined by computer hardware and software with a coding method for interpretation.
What is Unicode?
A universal character encoding system supporting all world languages (first 128 characters match ASCII).
How does one’s complement work?
Each binary digit is inverted (0 becomes 1, 1 becomes 0) to represent negative numbers.
How does two’s complement work?
Each binary digit is inverted, and 1 is added to the right-most bit.
Why is two’s complement preferred to one’s complement?
It simplifies binary addition and subtraction.
What are the weightings for an 8-bit two’s complement representation?
-128, 64, 32, 16, 8, 4, 2, 1
What is the smallest unit of memory in a computer?
A byte
What are common multiples of a byte?
16-bit, 32-bit, and other multiples of 8
How many bytes are in 1 KB (kilobyte) using the SI system?
1000
How many bytes are in 1 MB (megabyte) using the SI system?
1,000,000 bytes.
How many bytes are in 1 GB (gigabyte) using the SI system?
1,000,000,000 bytes
How many bytes are in 1 TB (terabyte) using the SI system?
1,000,000,000,000 bytes
How many bytes are in 1 PB (petabyte) using the SI system?
1,000,000,000,000,000 bytes
What is the IEC (International Electrotechnical Commission) binary system for memory measurement?
A system based on powers of 2 rather than 10
How many bytes are in 1 KiB (kibibyte) using the IEC system?
1,024 bytes (2¹⁰)
How many bytes are in 1 MiB (mebibyte) using the IEC system?
1,048,576 bytes (2²⁰)
How many bytes are in 1 GiB (gibibyte) using the IEC system?
1,073,741,824 bytes (2³⁰)
How many bytes are in 1 TiB (tebibyte) using the IEC system?
1,099,511,627,776 bytes (2⁴⁰)
How many bytes are in 1 PiB (pebibyte) using the IEC system?
1,125,899,906,842,624 bytes (2⁵⁰)
What system should be used to measure internal memory like RAM?
The IEC binary system
How many bytes are in 64 GiB of RAM?
64 × 2³⁰ = 68,719,476,736 bytes
Why is hexadecimal often used instead of binary?
It is easier to read and manage compared to long binary sequences.
What is a memory dump?
The process of outputting the contents of memory to a screen or printer.
Why is hexadecimal used in memory dumps?
It makes fault tracing and debugging easier for developers.
What is Binary-Coded Decimal (BCD)?
A number system where each denary digit is represented by a 4-bit binary equivalent.
Where is BCD commonly used?
In calculator and clock displays for easy conversion between computer output and denary.
Why is Binary-Coded Decimal (BCD) used for monetary values?
It ensures exact representation of decimal values, preventing significant errors in accounting.
How does BCD handle sums that produce non-denary digits?
By adding 0110 (denary 6) when necessary to maintain correct decimal representation.
What does ASCII stand for?
American Standard Code for Information Interchange.
When was ASCII originally set up and later updated?
Set up in 1963 and updated in 1986
How many bits are used in the standard ASCII code?
7-bit codes (0 to 127 in denary or 0 to 7F in hexadecimal)
What does the ASCII character set include?
Letters, numbers, standard keyboard characters, and 32 control codes
How does the ASCII code distinguish between uppercase and lowercase letters?
The sixth bit changes from 1 (lowercase) to 0 (uppercase), making conversion easy.
What is Extended ASCII, and why was it introduced?
It uses 8-bit codes (128 to 255 in denary or 80 to FF in hex) to support non-English characters and drawing symbols.
What is Unicode, and why was it developed?
A coding system designed to represent all languages globally, overcoming ASCII’s limitations.
How does Unicode differ from ASCII in terms of storage?
Unicode supports up to four bytes per character, while ASCII uses only one byte.
What are the five goals of Unicode Version 1.0 (1991)?
- Universal standard covering all languages and writing systems.
- More efficient than ASCII.
- Uniform 16-bit or 32-bit encoding.
- Unambiguous encoding for consistent character representation.
- Reserved code space for private character assignments.
How does Unicode benefit languages like Russian, Greek, and Japanese?
It allows these languages to be represented in a computer, supporting diverse writing systems.
