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Numbers and Hardware
AS Comp
Question | Answer |
---|---|
What is BCD? | Binary Coded Decimal - A value that is used to check against a database. The value holds no real value. |
What is 39 in binary? | 00100111 |
What is 39 in hexadecimal? | 27 |
What is 39 in octal? | 47 |
What is sign and magnitude? | Where you change the first digit into a sign to show that it is positive or negative. |
What is the problem with sign and magnitude? | That the first bit will have to be moved if the number is greater than 127 or less than -127. This is difficult for a computer to track. |
What is 00100111 add 01001001? | 01110000 |
What does the Program Counter do? | Contains the address of the next instruction for the processor. The counter is incremented to find the next instruction. This is altered when an interrupt comes in. |
What does the MAR do? | Memory Address Register - It is where the instruction from the PC is stored for use by the CPU. |
What does the MDR do? | Memory Data Register - It finds the instruction from the address in the MAR and holds the instruction that the MAR has the address for. |
What does the CIR do? | Current Instruction Register - Takes the instruction from the MDR. Then splits up the command and sends parts to be decoded. It also holds the address of the data used in the instruction. |
What is the ALU? | Arithmetic and Logistics Unit - it works out the numerical equations given to it by the CPU |
What is Cache RAM? | A highspeed RAM that acts as a buffer between the other units and processor. |
What is MICR? | Magnetic Ink Character Recognition - used on cheques so humans and computers can read it. |
What is OCR? | Optical Character Recognition - A scanner and program that reads characters and inputs them into data. |