| MP3 | What is a compressed audio format? |
| Recording the pixel colour and then the number of consecutive pixels of that colour instead of just recording each individual one | What is Run Length Encoding? |
| By recording a word's ID/location within a dictionary instead of the actual word itself, that way only the very small ID needs to be stored which saves space | How does dictionary based compression work? |
| non-encrypted - plaintext
encrypted - ciphertext | In encryption, what are the names for encrypted and non-encrypted text? |
| Vernam cipher | What is the name of the only encryption method said to be unbreakable? |
| - equal to or longer in characters than the plaintext
- truly random
- used only once | What are the 3 requirements for a one-time pad/key? |
| 00001111
00110011
01010101 | When creating a truth table, what is the sequence of binary inputs for each column? |
| Adds the contents of the memory address to the accumulator | What does the ADD code do? (LMC) |
| Subtract the contents of the memory address from the accumulator | What does the SUB code do? (LMC) |
| Store the value in the accumulator in the memory address given | What does the STA code do? (LMC) |
| Load the accumulator in the memory address given | What does LDA do? (LMC) |
| Branch - use the address given as the address of the next instruction | What does BRA do? (don't say hold up tiddies) |
| Branch to the address given if the accumulator is zero | What does BRZ do? (LMC) |
| Branch to the address given if the accumulator is zero or positive | What does BRP do? (LMC) |
| Input into the accumulator | Wgat dies INP do? (LMC) |
| Output contents of accumulator | What does OUT do? (LMC) |
| Stops the execution of the program (halt) | What does HLT do? |
| Used to indicate a ocation that contains data | What does DAT do? (LMC) |
| Atomicity, Consistency, Isolation, Durability | What does ACID stand for? |
| - A single logical operation on data
- booking a movie ticket | In the context of databases, what is a transaction and give one example? |
| - A transaction is either processed in it's entirety or not at all
- Even in the case of a hard disk crash or power cut, the transaction won't be processed incompletely | What is Atomicity? |
| Ensures that no transaction can violate any of the defined validation rules for maintaining the intergrity of the database | What does Consistency ensure? (ACID) |
| In a system where more than one transaction is being processed simultaneously, they won't affect each other | What is Isolation? (ACID) |
| Ensures that once a transaction has been commited, it will remain so, even in a power cut | What is durability? (ACID) |
| Record Locking | What is a technique used to avoid updates being lost in a database from multiple users editing at the same time? |
| Preventing all other access to a document while one user has it open | What is record locking? |
| Deadlock - when both users are locked out | What is a potential issue with record locking? |
| 8 bits | How many bits in a byte? |
| A single character of text | What can be stored in one byte? |
| kilobyte is 1000 bytes, kibibyte is 1024 bytes | What is a kilobyte and what is a kibibyte? |
| 065 | What is the ASCII code for A? |
| 097 | What is the ASCII code for a? |
| the one where most significant bit is a sign bit | Which one is sign and magnitude? |
| Sacrifices accuracy for range | What's the problem with fixed point binary? |
| Moving the binary point of a floating point number to provide the maximum level of precision | What is the point of normalisation? (binary) |
| When a number is too small to be represented in the allocated number of bits | In binary, what is underflow? |
| When the result of a calculation is too large to be held in the number of bits allocated | In binary, what is overflow? |
| Increases range but reduces the precision | In floating point, what effect does moving the decimal point right have on the number's range and precision? |
| 0.5, 0.25, 0.125, 0.0625 | What are the first 4 decimals after the point in floating point binary? |
| 0 is positive, 1 is negative | In floating point binary, which sign bit is + and which is - (0 and 1) |
| After the sign bit (eg. 01101001 = 0.1101001) | Where is the implied decimal point in a floating point notation? |
| Right | In floating point, which way do you move the decimal point for a positive exponent? |
| Do two's complement on the mantissa and then continue normally (REMEMBER TO ADD THE '-' SIGN TO THE ANSWER!!) | In floating point, what do you do if the mantissa is negative? |
| To maximise precision | In the context of binary, what is the purpose of normalisation? |
| - Move the decimal so that the digit after it is significant (not 0)
- Change the exponent as well to compensate | In floating point, how do you normalise? |
| Right (the one on the smaller end) | In binary, which side (right or left) is the least significant bit on? |
| Left (the larger end) | In binary, which side is the most significant bit on? (right or left) |
| All the bits move right or left | What is a logical shift? |
| The sign bit stays the same in an arithmetic shift | What's the difference with an arithmetic shift compared to a logical shift? |
| Divides by 2 | What effect does shifting a binary number one to the RIGHT have on it's value? |
| Multiplies by 2 | What effect does shifting a binary number one to the LEFT have on it's value? |
| Set selected bits to 1 without affecting the other bits | What is the use of an OR mask? |
| an AND mask | Which mask can be used to set particular bits to 0? |
