OCR GCSE Computer Science Paper One Revision

Flashcards generated from a lecture on OCR GCSE Computer Science Paper One.

What is the job of the CPU?

To carry out program instructions using data.

What is the ALU?

Arithmetic Logic Unit. It carries out the maths and logic needed to carry out instructions.

What is the role of the Control Unit in a CPU?

It coordinates the fetch-execute cycle and decodes instructions.

What is Cache memory?

A small, fast type of memory that holds frequently accessed items.

What are Registers?

Very small and very fast memory where the workings out of the CPU goes.

What does the Memory Address Register (MAR) do?

Stores the address of the location in memory being accessed.

What does the Memory Data Register (MDR) do?

Stores the actual data or instruction that has just been fetched or will be written to memory.

What is the purpose of the Program Counter?

Stores the address of the next instruction to be fetched from memory.

What is the function of the Accumulator?

Holds the results of ALU calculations.

What is Von Neumann architecture?

A CPU structure executing a fetch-execute cycle.

What are the three stages of the fetch-execute cycle?

Fetch, Decode, Execute

What is the clock speed of a CPU?

The rate at which the fetch-execute cycle is carried out, measured in gigahertz.

What is the benefit of having multiple cores in a CPU?

Multiple cores allow instructions to be executed at the same time.

What are Embedded systems?

Computers held inside other devices, typically with a single, specific purpose.

What does primary storage consist of?

RAM and ROM

What is secondary storage?

Storage where the vast majority of programs and data are stored long term. It is non-volatile.

What is virtual memory?

The operating system uses part of secondary storage as an extension of RAM when RAM is full.

What program does ROM contain?

Contains the program that runs as soon as you boot up your computer, which loads the operating system into RAM.

What are the three main types of secondary storage?

Magnetic, optical, and solid-state.

What is an example of magnetic storage?

A hard disk drive (HDD).

What is an example of optical storage?

A DVD.

What is an example of solid-state storage?

Solid State Drives (SSDs).

What is a bit?

A zero or a one.

What is a nibble?

Four bits.

What is a byte?

Eight bits.

What is a kilobyte?

A thousand bytes.

What do we use to represent characters in binary?

Character sets.

What are two big character sets?

ASCII and Unicode.

What is a pixel?

A block of colour.

What is the resolution of an image?

The number of pixels in an image.

What is metadata?

Data about data.

What is sample rate?

The number of samples taken per second of an audio signal.

What does compression do?

Reduces filesize.

What are two types of compression?

Lossy and lossless compression.

What are LANs and WANs?

LAN is a local area network over a small area, a WAN is a wide area network over a bigger area.

What happens in a client-server network?

A client requests something and the server responds.

What are the two types of network topologies?

Star and mesh.

What does a Wireless Access Point (WAP) do?

Provides a wireless signal.

What does a router do?

Forwards packets between networks.

What does a Network Interface Card (NIC) do?

Enables you to plug in things like Ethernet cables.

What is the cloud?

It's where we're holding computer files or some software, and we access it through the internet.

What are protocols?

A set of rules enabling devices to communicate.

What does TCP do?

It splits data into packets and also handles errors.

What are POP, IMAP, and SMTP?

POP and IMAP are for emails being received, whereas SMTP is for sending mail.

What is SQL injection?

The attacker tries to put in some SQL code into usually a user input form to try and interact with the database behind the scenes.

What is a brute force attack?

The attacker tries every combination of something like a password.

What is a denial of service attack (DoS attack)?

The attacker tries to deny service to legit users by flooding a device with lots and lots of new traffic, causing it to crash.

What are social engineering attacks?

Attacks that target humans, not the actual computer. They're trying to gain information or money from the poor person involved.

What is malware?

Malicious software.

What is penetration testing?

Where an organization will often pay somebody else to try and attack their system.

What does a firewall do?

Checks packets coming into and going out of the network.

What is encryption?

Where you scramble data so that only those with a key who are authorized can decrypt the data and understand the text.

What is the operating system?

Software which manages hardware and other programs on the computer.

What are GUIs?

Graphical User Interfaces.

What does defragmentation software do?

This only works on magnetic hard drives; you would not really use it on an SSD because it doesn't have the same weakness, which is where you've got the data stored on the disk affects how fast it is to access.

What is the Data Protection Act?

This is all about personal data and the responsibility of organizations to look after it.

What is the Computer Misuse Act?

This is the law which makes both of these things (hacking and malware) illegal.

What is the Copyright, Designs and Patents Act?

This is all about intellectual property, so ideas people have—things which are quite easy to steal unless you've got a law like this one.