5. Step 1.The user presses the capital letter D (shift+D key) on the keyboard. Step 4.After processing, the binary code for the capital letter D is converted to an image, and displayed on the output device. How is a letter converted to binary form and back? Step 2.An electronic signal for the capital letter D is sent to the system unit. Step 3.The signal for the capital letter D is converted to its ASCII binary code (01000100) and is stored in memory for processing.
6. BIT BIT stands for Binary Digit It is the smallest size of computer data storage It can either store a binary “0” or a “1” 0 1 OR Therefore a BIT can have 2 different values or combinations.
7. Byte – a group of 8 bits. Therefore, a byte can represent up to 28=256 values. The values can range from 0 to 255 or from -128 to 127. The fundamental data unit of a computer. ? ? ? ? ? ? ? ?
8. Data Representation 2 Presentation Unit 2 Slide 8 BYTE The 256 possible combinations are shown below:
9. Data Representation 9 Bytes as unsigned integers Base 2 number using positional notation 0 0 1 0 0 0 1 1 128 64 32 16 8 4 2 1 most significant bit least significant bit Value is 32 + 2 + 1 = 3310
10. CHARACTER 8 bits = 1 byte = 1 character (like ‘A’) One byte represent one character such as A, 7, 9 and @ For example the 01000110 represented a letter “F” 0 1 0 0 0 1 1 0 = F
15. CLOCK SPEED MEASUREMENT “SPEED” means how fast it can process data Every processor contains a system clock. The system clock control the speed of all operations within a computer. The clock speed unit is measured in Hertz. A Hertz is one cycle per second.