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44 Cards in this Set
- Front
- Back
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CPU(Computer Processing Unit)
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Executes programs using the fetch decode execute cycle.
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Memory
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Stores program operations and data while a program is being executed. There are several types of memory, including: registers, cache, RAM and virtual memory. |
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Storage
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Stores programs and files long term, even when they are not in use. Devices such as hard drives, USB memory sticks or SD cards are used to store files such as photos, music and software applications long term. |
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Four key factors about CPU that affect its performance are:
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.Cores .Clock speed .Cache size .Processor type
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The Motherboard
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A circuit board that connects the CPU to the memory and all the other hardware. The CPU sits on the motherboard (also called the logic board). |
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Buses
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Circuits on the motherboard that connect the CPU to other components. There are many buses on the motherboard. A bus moves instructions and data around the system. The speed of a bus is measured in megahertz (MHz). The faster the bus, the faster data is communicated. The speed of the motherboard is defined by the bus speed. |
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The FSB(front-side bus) contains two types of bus:
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* The address bus only sends data in one direction - from the CPU to RAM. * Data bus - This sends data to the memory or receives data from the memory. * Data can flow both ways along the data bus. |
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RAM
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The main place for storing instructions and data whilst a program is being executed. It is also called main memory. Program data is copied into RAM before the CPU can run the program. |
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RAM
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Usually measured in gigabytes (GB). The more gigabytes of RAM a computer has, the more programs and operations it can handle at the same time. |
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Virtual memory
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A section of volatile memory created temporarily on the storage drive. It is created when a computer is running many processes at once and RAM is running low. |
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ROM (Read Only Memory)
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A flash memory chip that contains a small amount of non-volatile memory. Non-volatile means that its contents cannot be changed and it retains its memory after the computer is turned off. |
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Algorithms
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They're designed to solve problems. Programming languages are used to implement algorithms. They create the programs (software) that communicate instructions to a computer. |
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Types of programming language
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Input data from a device such as a keyboard output data to a device such as a screen process calculations like addition and subtraction. Process decisions based on certain conditions being met. Process repetition for a certain number of times, or while a condition is met, or until a condition is met.
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Process virtual machine
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A programming environment that allows a program written for one type of machine to run on other types of machine without any changes being necessary. For example, the Java Virtual Machine allows Java bytecode produced on a Microsoft Windows OS to run on a Unix OS without any changes. |
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System virtual machine
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A software application run by the host operating system of a computer which emulates a second operating system. This permits the installation and execution of software applications on the virtual machine (VM) as if they were being installed and run on a separate computer. |
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IDE (Integrated Development Environment)
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An application used to create software. An IDE can often support different languages. IDEs have a number of different tools and functions that assist a developer in the creation of software. |
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Auto-completion (or code completion)
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This is designed to save time while writing code. As you start to type the first part of a function, it suggests or completes the function and any arguments or variables.
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Bracket matching
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This is used for languages that use pairs of brackets to mark out blocks of code. It allows the code to be read and understood more quickly. If you forget to close a bracket while writing, coloured sections may help you to detect missing brackets. |
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Syntax checks
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This recognises incorrect use of syntax and highlights any errors.
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Translator
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This compiles or interprets the code.
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Auto documentation
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This explains the function and purpose of the code, eg by noting the modules and variables used, and its expected behaviour, and collates this into a text file that can be used by other developers to understand how and why the code was created.
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Libraries
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These provide functions that are not included in the core part of the programming language. These functions can be imported and used at the start of the program code. For example, in python the Turtle Graphics library provides access to some simple drawing and graphics tools. |
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Build automation
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These tools save time by automatically doing the processes that would otherwise be done by hand. These could include testing or compiling. These tools are extremely useful when a program has many thousands of lines of code. They improve the quality of the software, minimising bad software builds as well as saving time and money. |
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Debugger
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A program within the IDE that is used to detect errors. If the debugger detects errors, it may suggest what the type of error is and what line it is on. |
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Errors
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There are different types of errors, or bugs, which can prevent computer programs from working in the way they should. Three of the key error types are runtime, syntax and semantic. |
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Runtime errors
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Errors which will cause the program or computer to crash even if there appears to be nothing wrong with the program code. Running out of memory will often cause a runtime error. This could be because instructions have been written in the wrong order. |
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Syntax errors
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Syntax errors are mistakes in the way that the code is written. Translators can only execute a program if it is syntactically correct. Common syntax errors include spelling mistakes, incorrect use of punctuation and the use of capital letters. |
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Semantic errors/Logical errors
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Where the program works but produces different results from what you designed or expected. A program with semantic errors will execute without any errors being reported.
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Debugging
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The process of working through the program in a systematic way to eliminate any flaws or glitches. A debugger program is usually included within the IDE. |
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Stepping
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A method of debugging which executes the code one line at a time to check for errors. A debugger can also use breakpoints, points in the code where the program can be stopped to see what is happening and check for errors. A breakpoint can be created by the programmer to halt the program after a certain number of lines of code. |
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Network
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A network is created when more than one device is connected together. A network can be a small collection of computers connected within a building (eg a school, business or home) or it can be a wide collection of computers connected around the world. |
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LAN (Local Area Network)
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A network of computers within the same building, such as a school, home or business. A LAN is not necessarily connected to the internet. |
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WAN (Wide Area Network)
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Created when LANs are connected. This requires media such as broadband cables, and can connect up organisations based in different geographical places. The internet is a WAN. |
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VPN (Virtual Private Network)
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Usually hosted securely on another network, such as the internet, to provide connectivity. VPNs are often used when working on secure information held by a company or school.
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WPAN (Wireless Personal Area Network)
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Allows an individual to connect devices (such as a smartphone) to a desktop machine, or to form a Bluetooth connection with devices in a car. A wired personal network is called a PAN (personal area network). |
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Topologies
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There are different ways of setting up a LAN, each with different benefits in terms of network speed and cost. Three of the main topologies include bus, star and ring. |
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Bus Network
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All the workstation, servers and printers are joined to one cable - 'the bus'. At each end of the cable a terminator is fitted to stop signals reflecting back down the bus. |
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Ring Network
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Each device (eg workstation, server, printer) is connected in a ring so each one is connected to two other devices. Each data packet on the network travels in one direction. Each device receives each packet in turn until the destination device receives it. |
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Star Network
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Each device on the network has its own cable that connects to a switch or hub. This is the most popular way of setting up a LAN. You may find a star network in a small network of five or six computers where speed is a priority. |
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Wired Connections
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Computers can be connected through Ethernet cables which connect to the Ethernet port. Connecting hardware such as a router has Ethernet ports.
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Wireless Connections
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Computers can make a wireless connection if they have a wireless NIC. A wireless router provides a connection with the physical network. A computer device needs to be within range of the router to get access. A wireless connection uses radio signals to send data across networks. The wireless adapter converts the data into a radio signal and the wireless receiver decodes it so that the computer can understand it. |
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Networking Hardware
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Computers need networking hardware in order to connect to each other. Routers, Hubs, switches and bridges are all pieces of networking equipment that can perform slightly different tasks. A router can often incorporate hubs, switches and wireless access within the same hardware. |
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Routers
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Form a LAN by connecting devices within a building. It also makes it possible to connect different networks together. Homes and businesses use a router to connect to the internet. A router can often incorporate a modem within the hardware. |
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Modems
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Enables a computer to connect to the internet over a telephone line. A modem converts digital signals from a computer to analogue signals that are then sent down the telephone line. A modem on the other end converts the analogue signal back to a digital signal which another computer can understand. |
