AS IT

Question	Answer
1.01 Data, information and knowldge	Data is raw numbers, letters, symbols, sounds or images without meaning. Information is data with context and meaning. When data items are given context and meaning, they become information. Data is given context by identifying what sort of data it is. This still does not make it information but is a step on the way to it becoming information. Knowledge is information to which human experience has been applied. Knowledge is basically what a person knows. Knowledge requires a person to understand what information is, based on their experience and knowledge base.
1.02 Sources of data	Static data is data that does not normally change. Static means 'still'. Static Data is either fixed or has to be changed manually by editing a document. Dynamic data is data that changes automatically without user intervention. Dynamic means 'moving'. It is data that updates as a result of source data changing. Dynamic data is updated automatically without user intervention. Direct data source is data that is collected for the purpose for which it will be used. Indirect data source is data that was collected for a different purpose (Secondary Data)
1.03 Quality of information	The quality of information is determined by a number of attributes. Accuracy: Data must be accurate in order to be considered of good quality. Relevance: Information must be relevant to its purpose. Age: Information must be up to data in order to be useful. Level of detail: There needs to be the right amount of information for it to be good quality. It's possible to have either too little or too much information provided. Completeness: All information that is required must be provided i order for it to be of good quality.
1.04 Coding, encoding and encrypting data	Coding is representing data by assigning a code to it for classification or identification. Encoding is storing data in a specific format. Encryption is the scrambling of data so it cannot be understood without a decryption key to make it unreadable if intercepted. SSL: Secure Sockets Layer TLS: Transport Layer Security HTTPS: Hypertext Transfer Protocol Secure
Advantages and disadvantages of coding data	There are a number of reasons for coding data. The advantages of coding data can be summarized as follows: 1. Presentation: Data can be presented in small spaces, such as on labels or when listing large amounts of data. 2. Storage: Less storage space is required because less characters are used to store the data.
3. Speed of Input: data can be input more quickly because only a few numbers or letters need to be input instead of whole words or phrases. 4. Processing: Processors can process data more quickly because they only have to process the coded data instead of the whole word or phrase.	5. Validation: It's possible to validate data by checking it is particular length or within a certain range or matching other rules. For example, an international vehicle registration code must be a maximum of three letters and not contain any numbers or symbols. 6. Confidentiality: Sometimes data can be coded so that it only makes sense to people who know what the codes mean.
7. Consistency: If the correct codes are used then data will be input consistently without spelling errors, making it easier to be searched or summarized.	The disadvantages of coding can be summarized as follows: 1. Limited codes: There may not be enough codes available to use, meaning that more letters or numbers need to be added. For example, with international vehicle registration codes, E is already used for Spain and so Egypt has to use ET and Ecuador has to use EC. Now that Egypt has taken ET, Ethiopia can't use it and so has to use ETH.
2. Interpretation: Codes may be difficult to interpret. For example, with international vehicle registration codes, somebody might look at ET and assume it is Ethiopia or look at S and assume it is Spain. It's even more difficult when considering international dialing codes that are represented by numbers.	3. Similarity: Some letters and numbers can be difficult to distinguish as O and 0 or Z and 2, especially if handwritten. With codes, it's difficult to guess what the value might be and so mistakes can occur. At least with words it's possible to guess what the badly written letter might be.
4. Efficiently: If a user inputting codes does not know what code to use . then they will not be able to enter the data efficiently. Instead they will have to look up the code. 5. Missing information: It's possible that some information gets lost during the process of coding. For example, if devices on a network are coded as L for laptop, P for printer, D for desktop computer and M for mobile phone, then information about whether or not the mobile phone or laptop is touch screen is lost.	Encoding data When data is encoded, it is stored in a specific format. Computers use binary digits which are 1's and 0's. One mean on and zero means off. A typical binary number would look like this: 11011010. Therefore, data needs to be encoded into a format which the computer understands. Codecs are programs that are used to encode data for images, audio and video. The codecs are also needed to read the data.
1.05 Checking the accuracy of data	Validation is the process of checking data matches acceptable rules. Verification is ensuring data entered into the system matches the original source. Proof reading is the checking of information manually. Presence check: A presence check is used to ensure that data is entered. If data is entered, then it is accepted. If data is not entered, then the user will be presented with am error message asking them to enter data.
Range check: A range check ensures that data is within a defined range. The following symbols are used are used when comparing with a boundary: > greater than < less than >= greater than or equal to <= less than or equal to	Type check: A type check ensures that data must be of a defined data type. Length check: A length check ensures data is of a defined length or within a range of lengths. Format check: A format check ensures data matches a defined format. It is sometimes known as a picture check and the data has to follow a pattern. Lookup check: A lookup check tests to see of data exists in a list. Check digit: A check digit is a number (or letter) that is added to the end of an identification number being input.
Verification Verification is the process of checking that the data entered into the computer system matches the original source. Visual Checking: A method of verification can be for the user to visually check that the data entered matches the original source. Double data entry: Another method of verification is to input data into the computer system twice.	The need for both validation and verification By using both validation and verification, the chances of entering incorrect data are reduced. If that data is incorrect passes a validation check, then the verification check is likely to spot the error.
Proof Reading What is Proof Reading?	Proof reading is the process of checking information. For example, when a book is written it is checked for spelling errors, grammar errors, formatting and accuracy. When proof reading a document, it is best to have a proof reader who is different from the original author of the document, as they will be able to check the work objectively and identify errors. However, it is possible for the original author to proof read their own document, but they may not notice some of their own errors. When data is input, it is usually proof read by the person inputting the data.
2.01 Hardware	Hardware is a physical component of a computer system. Hardware is categorized into input, output and storage devices. Device is a hardware component of a computer system consisting of electronic system. Output devices are devices used to communicate data or information from a computer system. Storage devices are devices used to store data onto a storage medium.
Input devices are devices that allows data to be entered into a computer system. Storage medium is the medium on which data is stored.	Volatile is when data is lost when there is no power. Non-volatile is when data remains where there is no power.
Internal Hardware Devices 1. Central Processing Unit - The central processing unit (CPU) is the brain of a computer. It is part of the computer that carries out calculations, executes instructions and processes data. It includes the arithmetic logic unit (ALU) and control unit (CU).	2. Motherboard - The motherboard is a printed circuit board (PCB) which connects the main components of a computer. 3. Random access memory (RAM) is memory that is used to store currently active programs and data. The more RAM that is available to the computer, the more data and programs can be used at the same time. RAM is volatile.
4. Read-only memory - Read-only memory (ROM) is memory that, once it has been written to, can no longer be changed. It is permanent and it is non-volatile, which means that when there is no power to the computer, the contents of the ROM will be retained. Tip: In a computer, there is usually some ROM that stores the instructions to boot (start) the computer.	5. Graphics card - it is a printed circuit board that connects to one of the motherboard's expansion slots. Its purpose is to generate the signals needed to display the output image from the computer. 6. Sound card - the purpose of a sound card is to generate the signals needed to output sound from the computer to a speaker or set of speakers.
7. Hard disk drive - A hard disk drive (HDD) is the most common form of secondary storage for the computer due to its relatively low cost per MB (megabyte). The hard disk drive consists of two main parts: the device that is the electronics which store the data, and the disk that is the medium onto which the data is stored.	8. Solid state drive - A solid state drive (SSD) is another secondary storage device that is non-volatile. However, there are no moving parts and the data is stored onto flash memory. SSD's are also non-magnetic and so are not susceptible to damage from too close, strong magnetic fields.
External Hardware Devices 1. Cloud - Cloud computing is a term that refers to anything where computing services are hosted over the internet and not in the same physical location as the computer being used. Examples of cloud storage for personal use include: >OneDrive >Google Drive >Dropbox >Box	2. Monitor 3. Keyboard - A keyboard consists of a number of buttons which are used to input text or control parts of an interface. 4. Mouse - a mouse is a pointing device which allows objects to be selected and manipulated on the screen.

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	Created by Kaylee Whorms about 7 years ago