Data Representation
Table of Contents
- Easy Level Magic Review Questions – igcse computer science
- Medium Level Magic Review Questions
- Hard Level Magic Review Question
Easy Level Magic Review Questions – igcse computer science
Explain how hexadecimal is used in memory dumps?
– Hex notation is often used when developing new software or trying to debug programs.
– Contents of computer memory can hold the key to solve many problems.
– When the memory contents are output of a printer or monitor, this is called hex dumps.
– Easier to work with 5C3F rather than 0101110000111111, for example.
– In a hex dump, each byte (8-bits) is represented as a two-digit hexadecimal number.
– Hex dumps are commonly organized into rows of 8 or 16 bytes, sometimes separated by whitespaces.
To divide a number, what is the effect on the binary shift?
– The binary shift moves all the digits in the binary number along to the right.
– Fills gaps after the shift with 0.
What is data?
– Information coded in format ready for processing.
– Raw fact and figures.
– Can be in form of numbers, symbols or alphanumeric characters.
What does ASCII and Unicode have in common?
– Both represent each character using binary number.
What is analogue data?
– Data sent or received continuously.
– Varies over a wide range.
– Continuous data that our senses process daily like sound, light, waves, impulses on skin.
What is digital data?
– Data that consists of recognizable binary digits.
– Represented in values of 1 and 0.
– Computer can process this data.
Explain file formats?
– Method we choose to store different data on a computer.
– Certain file formats are designed for a particular type of data like text, images or multimedia.
– Ex: .doc, .rtf, .csv, .xls, .mp3, .wav, .bmp, .jpg, etc.
Medium Level Magic Review Questions
What is Unicode?
– Uses 16 bits so have possible to 65 536 characters.
Useful Tip for Exam Calculation Question
- Explain the memory size ladder?
- 1. 1 Nibble – 4 bits
- 2. 1 Byte – 8 bits
- 3. 1 Kilobyte – 1024 bytes
- 4. 1 Megabyte – 1024 kB
- 5. 1 Gigabyte – 1024 MB
- 6. 1 Terabyte – 1024 GB
What is ASCII?
– American Standard Code for Information Interchange.
– Uses 8 bits so have possible 256 characters.
Explain how hexadecimal is used in MAC addresses?
– Uses 12 hex number to identify each device in a network.
To multiply a number, what happend to the binary shift?
– It moves all the digits in the binary number along to the left and fill the gaps after the shift with 0.
Explain the two parts that make up a typical MAC address?
– The first half of the MAC address is the identity number of the manufacturer of the device (NN-NN-NN). – The second half is the serial number for the device (DD-DD-DD). – For example (00-1C-B3-4F-25-FE) is the MAC address produced by the Apple cooperation and 4F25FE is the serial number.
Explain MAC addresses?
– Media Access Control
– Unique number that identifies actual device connected to the internet or network.
– Embedded in hardware when product is made in factory.
– User cannot change it.
– On a computer, MAC address is a unique code built in the NIC.
– No two computers have the same MAC address.
– Made up of 48 bits of data, written at 12 hex characters.
What is the effect of dividing by different numbers on the binary shift?
– to divide by two, all digits shift one place to the right
– to divide by four, all digits shift two places to the right
– to divide by eight, all digits shift three places to the right
– and so on
Explain the effect of different numbers on the binary shift?
– to multiply by two, all digits shift one place to the left
– to multiply by four, all digits shift two places to the left
– to multiply by eight, all digits shift three places to the left
– and so on
What is algorithm?
– Step by step set of instructions.
Explain denary number system?
– System of numbers with base of 10.
– Each unit increases by the power of 10.
– Also known as decimal or base 10.
– Standard number system used globally.
– Uses ten digits (0 1 2 3 4 5 6 7 8 9) to represent all numbers.
What is shifting?
– The process where binary numbers are multiplied and divided.
Explain data compression?
– It is when the bit structure is manipulated in such a way that data in file becomes smaller in size.
– Uses compression algorithm to manipulate the data.
– Two types = lossy and lossless.
Explain processor register?
– A local sotage space on a processor that holds data being processed by the processor.
– Occupy first postition in memory hierachy.
– Provides fast storage space and access to data.
– Can only store address of memory location instead of real data itself.
What is debug?
– Finding and fixing problem and errors in a program.
Hard Level Magic Review Question
Explain hexadecimal?
– Base 16 system.
– Used to simplify how binary is represented.
– A hex digit can be represented by any of the 16 digits: 0 1 2 3 4 5 6 7 8 9 A B C D E F.
– Each hex digit represents 4 bit binary sequence.
Explain binary number system?
– System of numbers with a base of 2.
– Each unit increases by the power of 2.
– Represent numeric values using two unique digits (0 and 1).
– Used by computing devices to represent electronic circuit voltage state. 0 is voltage input off and 1 is voltage input on.
– Known as base 2 number system.
Explain how hexadecimal is used in Web addresses?
– URL encoding converts characters into format that can be sent over the internet.
– So it uses ASCII character set.
– URLs often contain characters outside the ASCII set, so it must be converted using valid ASCII format.
– URL replace any unsafe ASCII characters with % followed by two hex digits.
– URL replace space with %20.
Explain how hexadecimal is used in HTML?
– HTML uses hexadecimal as a notation for colour.
– Hex colour notations are six digits long.
– Each hex notaton represent a different colour.
What are the reasons for MAC address to change to use LAA?
– Some software used on mainframe system needs all MAC address of devices to fall into strict format.
– It is sometimes needed to bypass a MAC adress filter on router or firewall.
– To pass certain restrictions, we need to emulate unrestricted MAC adresses.
Explain the different types of MAC address?
UAA
– Universally Administered MAC adress.
– Set by manufacturer or factory.
LAA
– Locally Administered MAC adress.
– Easier to be indetified by network personnel as it conforms to network or site’s naming convention.
Explain hardware register?
– Specific to different types of hardware.
– Used to convey a signal.
Common Exam Style Questions
- Explain lossless compression?
- – Method of compression that loses no data in the process.
- – Rewrite the data in the file in a much more efficient way.
- – Since no data is lost, the rewritten file will be larger than those compressed with lossy compression.
- Explain lossy compression?
- – Attempt to remove any repetitive or unimportant information.
- – Used to reduce the data size for storage, handling, and transmitting content.
- Explain registers?
- – Small piece of memory where values can be held.
- – Not part of primary or secondary storage.
- – Have very fast read and write rate of data.
- – Have faster read and write rate of data that primary or secondary storage.
- – Different type of register include processor and hardware register.
- – Can hold an instruction, storage address, any kind of data.
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