Computer systems Flashcards
State what is meant by a sign bit?
A sign bit is defined as the first digit of a binary number which indicates if the number is a positive number or a negative number
State what having a sign bit of 1 indicates about a number?
Having a sign bit of 1 indicates that negative number = true, meaning that the number will be negative.
State what is meant by having a sign bit of 0?
A number with a sign bit of 0 means that negative = false, this means that the number will be a positive number
Describe the twos complement convention to determine the range of values for a positive number?
0 to (2 to the power of the number of bits in the binary number) -1
Describe the twos complement convention to determine the range of values for a negative number?
We still have only the 2 to the power of number of bits in the binary number, values but this time they are split evenly across positive and negative numbers e.g and 8 bit negative number will have a range of -128 to 127
State the mantissa of this number 1.00000001 * 2^11110?
The mantissa is the main number meaning it will be the number in the left 100000001
State the exponent of the number 1.00100101 * 2^1110
The exponent is the number on the right meaning the exponent is the power (1110)
State the effect of increasing the available number of bits for the mantissa will have?
An increase in the available number of bits for the mantissa will increase the precision of the number
State the effect that increasing the available number of bits for the exponent would have?
An increase in the available number of bits for the mantissa means that you increase the range of the number
State the effect of a decrease in the available number of bits for the mantissa would have?
Decreasing the available number if bits for the mantissa would reduce the precision of the number
State the effect of a decrease in the number of bits available for the exponent?
A decreased number of bits for the exponent means that the range of the number will decrease
Describe how you determine the sign bit in floating point representation?
The sign bit will be a 0 if the number is positive and a 1 if the number is negative
Describe how you determine the mantissa in floating point representation?
To find the mantissa you remove the decimal point for the number and add on any aditional 0s at the end of the number.
Describe how you would determine the exponent in floating point representation?
In floating point representation we look at the number of places that the decimal point has moved
- If the decimal point has moved to the left then the exponent is positive
- If however the decimal point has moved to the right then the exponent is negative
Explain some of the similarities and differences between unicode and ASCII?
Both unicode and ASCII are methods of storing characters as binary values ASCII only stores 2^7 values and extended ASCII will store 2^8 however this is not enough values to include characters from other languages or emojis. Hence unicode uses 16 bits per character meaning that they have a 2^16 values that they could represent. The increased number of bits means that they can represent a larger number of characters useful for storing emojis or symbols for other languages of the world.
(Unicode has more bits and can therefore represent more characters)
State what is meant by a bit map?
A bitmap is defined as a grid of pixels
Explain what a bitmap does?
A bitmap is a grid of pixels where each individual pixel has a binary value that determines the colour of that given pixel. Bitmaps have a large file size as they must store each pixel in an image as a binary value with 24 bits per pixel.
State what is meant by a vector?
A vector consists of objects and attributes, Vectors are stored as separate objects. This means that they can be layered without overriding what is underneath and they do not leave unwanted gaps
State what is meant by an image being resolution independent?
An image that is resolution independent means that the image can be redrawn at any resolution.
Explain why vectors can be described as being resolution independent?
As they can re resized without causing pixelation as vectors are stored as individual objects meaning that they can be reshaped and resized without losing any quality.
State what the role of an address bus is?
The address bus is a bundle of wires that carries the identity of memory locations.
State the role of a data bus?
the data bus will retrieve data from the memory location that it is given and return this data to the CPU.
State the role of the control bus?
The job of the control bus is to indicate if the processor is reading from or writing to the main memory.
State the 4 components that make up the CPU?
- Cashe
- Registers
- ALU
- Control unit