Karteikarten
digital tech
Karten in diesem Stapel (16)
- 1UNIT 1CHAPTER 1 DIGITAL DATA
- 2REPRESENTING DATAData consists of raw facts.
When data is processed if gives us information. - 3STORING DATAComputers store data in digital format also known as binary. 0/1. When 8 bits are stored together they are known as byte. 2 bytes-16 bits. A nibble is 4 bits so 2 nibbles is 1 byte. Storage is measured in bytes. 1024 bytes-1KB. w1024 KB-1MG. 1024MG-1GB. 1024GB-1TB. Characters are known as ASCII. Every character has a pattern in binary.
- 4DATA TYPESData has to be stored in the most appropriate way. Data must be defined as a certain type before it is processed..Integer numbers can be positive for negative no decimal or fractional parts. Real numbers include whole numbers can have decimal and fractional parts and can be positive or negative.
- 5REPRESENTING IMAGESPixel is the smallest unit of a digital image and can have its own colour. Put together they create an image. Number of pixels on a screen depends on size of screen and graphics card used. Each pixel is stored as binary digits.
- 6BITMAP AND VECTOR-BASED GRAPHICSBitmap graphics are made up of a grid of pixels. using a phone to take a photograph or scan a picture you create a bitmap image. The more pixels the better the resolution-more storage space. Vector images are not made up of pixels but store the components. Very good quality and can be stored in smaller sizes.
- 7REPRESENTING SOUNDSample rate- Number of audio sound samples captured every second. Measured in Hertz. More samples taken the more accurate from the original sound. Bit Depth- Is the number of bits used to store each sound. Higher quality needs a higher bit depth. Bit rate-data measured in bits usually in kb per second.
- 8ANALOGUE TO DIGITAL CONVERSIONAnalogue signal is described as a various signal. Before a computer can processed analogue sounds it needs to be converted into digital (binary). Samples a sound wave at regular time intervals. Sound samples low-loss of quality. Sampling per second should be increased for better quality this is measured in hertz.
- 9DATA PORTABILITYCan transfer data from one computer to another or from one software application to another. Don't have to re-enter data. Different types of data needs to be stored using particular formats to ensure data is portable between different software applications or different computer systems.
- 10DATA COMPRESSIONUsed to convert digital data to as small a size as possible while still having good quality contained in the file. Data that has been compressed takes less time to upload and download. There are 2 main types of depression lossy and lossless.
- 11LOSSY COMPRESSIONReduces the file size by removing some of the data for example reducing the numbers of colours used in an image. Can result in a small loss of quality. Once a file has been compressed using this method data is permanently lost. JPEG is an example of this.
- 12LOSSLESS COMPRESSIONMaintains the quality of the file so no data is lost. Winzip software is an example of this. You do this by ZIPPING up the file so it can be sent over the internet. The file can be recreated UNZIPPED exactly as it was before it was compressed.
- 13UNIT 1CHAPTER 2 SOFTWARE
- 14SYSTEM SOFTWAREOfter described as the interface between computer hardware and user application programs. Application software enables the computer to do a particular task. Types of system software include the operating systems and utility programs. This is an essential piece of software Microsoft windows is a common one.
- 15MODES OF PROCESSINGReal-time processing data is processed immediately after its input. Output generated is processed quickly which influences the next input. Examples-airline/concert booking tickets. This is essential to avoid disasters.
- 16BATCH PROCESSING
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- GCSE IT Karteikarten am digital tech, erstellt von sophie naysmith am 13/03/2018.
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- sophie naysmith
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