1. DATA Unit 2 Topic 2

2. Different Types of Data ASCII code: ASCII - The American Standard Code for Information Interchange is a standard seven-bit code that was proposed by ANSI in 1963, and finalized in 1968. Originally a 7 bit code, extended to 8 bits. 7 bits does the characters, numbers and special symbols (128). The extra bit does another 128 special characters.

3. DEC HEX EBCDIC ASCII BINARY DEC HEX EBCDIC ASCII BINARY 9660-`0110 0000 11270 p0111 0000 9761/a0110 0001 11371 q0111 0001 9862 b0110 0010 11472 r0111 0010 9963 c0110 0011 11573 s0111 0011 10064 d0110 0100 11674 t0111 0100 10165 e0110 0101 11775 u0111 0101 10266 f0110 11876 v0111 0110 10367 g0110 0111 11977 w0111 10468 h0110 1000 12078 x0111 1000 10569 i0110 1001 12179`y0111 1001 1066A j0110 1010 1227A:z0111 1010 1076B,k0110 1011 1237B#{0111 1011 1086C%l0110 1100 1247C@|0111 1100 1096D_m0110 1101 1257D'}0111 1101 1106E>n0110 1110 1267E=~0111 1110 1116F?o0110 1111 1277F"DEL0111 1111

4. ASCII What happens in a Word Processor when a letter key is pressed on the keyboard? Example: a is pressed, a binary code of 0110 0001 is sent to the processor, and decoded as the letter a and shown on the screen. This is the same with numbers, i.e. 2 is pressed, a binary code of 0011 0001 is sent to the processor and decoded as the number 2. If numbers are to be used in a calculation then we will need a different software application as well as a different method of decoding.

5. Integer Numbers We use decimal numbers: 0,1,2,3,4,5,6,7,8,9,etc. There are other systems for counting and manipulating numbers. (Before 1969 this country counted money in the form of 12 pence to a shilling, 20 shillings to a £.) Computers use Binary, Octal, and Hexadecimal. The last two are different forms of Binary. Binary is the simplest form of counting and is computer friendly as it uses a simple switch – ON and OFF, or as we write it 0 and 1.

6. Binary A bit is either a 0 or a 1. A byte is a series of eight bits. ASCII uses eight bits (byte) to decode a keyboard character. Binary is usually displayed as a series of zero’s and one’s the length of a byte. We use a spreadsheet to calculate 7 + 5. When entering an equals into a cell the processor is ready for a calculation. 7 is converted into binary: 0000 0111. 5 is converted into binary: 0000 0101. Added together in binary = 0000 1100.

7. Conversion How to convert Decimal 113 into Binary. 113 / 2 = 56 remainder 1 (least significant bit) 56 / 2 = 28 remainder 0 28 / 2 = 14 remainder 0 14 / 2 = 7 remainder 0 7 / 2 = 3 remainder 1 3 / 2 = 1 remainder 1 1 / 2 = 0 remainder 1 (most significant bit). = 1110001 or commonly written as 0111 0001. Check: 1 x 2 0 = 1, + 1 x 2 4 = 16, + 1 x 2 5 = 32, + 1 x 2 6 = 64 Finally: 64 + 32 + 16 + 1 = 113.

8. Other Numbers Numbers more commonly come in the form of real numbers. These are numbers with a decimal point and are calculated differently to Integers. Sometimes there is still some rounding involved i.e. 1/3 rd can never be represented as a decimal, but with increasing decimal places the accuracy increases.

9. Graphics There are two types of graphics: –Bitmap – pixel based; –Vector – object-oriented based; Bitmap: The viewable area is divided into a grid – i.e. 600 x 800, or 1024 x 1024. This represents the amount of Pixels there are. Each pixel in a colour screen may contain a byte of information (one of 256 different colours). What is the amount of memory needed to show a picture at a screen resolution of 1024 x 1024?

12. Graphics Vector: Made up of geometric data, a line is defined by its end points, length, width, and colour, and displayed on the screen. The line can be magnified without distortion as it stays as a line in the computer memory, this gives the same accuracy of information. The bitmap image will distort (lose accuracy) as it is magnified as the pixel colour area is magnified. Vector images are smaller files as each pixel stores a byte of information.

15. Digital Sound Sound may be input using a microphone, a musical instrument, or a CD etc. Sound waves are analogue therefore they will need to be converted to digital for storage and playback through a computer. Sound is stored the same way as other information as binary digits. Computer hardware such as a sound card converts it so it can be read and stored. It is an analogue digital converter.

16. Digital Sound The quality and accuracy of the sound is determined by the sampling rate and the resolution of the sound card. Sampling Rate: how often the sound card takes a sample of the sound to store. The higher the rate the greater the accuracy. CD quality requires 44,000 samples per second. This is a frequency of 44kHz. Resolution: how accurate the amplitude of the sound can be measured. An 8 bit (1 Byte) sound card will allow 256 sound levels of amplitude, where a 16 Bit (2 Bytes) sound card will allow 65,536 sound levels of amplitude.

17. Output Format The different types of data already mentioned are displayed as outputs in various ways, i.e. print, screen, and sound. The make the information produced acceptable for its purpose the output format needs careful consideration. Rows of text, tables of lists, columns of numbers may only interest the specialist. Add image, slides, presentation techniques tailor the material to the intended audience from managers to the public. Suitable output format should be used, such as: Text, Numbers, Sound, Video, Graphics, Animation etc, using the most suitable software applications.

18. Output Media In what circumstances would the following output format be useful for? –A monitor screen; –A print out on paper; –A floppy disc or CD ROM; –An electronic signal – e-mail; –A projector; –A webcam.

19. Finally A computer print out of a list of information or a database report can contain too much information. Time may be taken up searching for the essential elements by managers. Careful thought by programmers may reduce the output by using search criteria for certain results, and save time. Remember this when you plan your database project for next year.