Higher Computing - Computer Systems 2

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble.

   bit      decreased      elements      exponent      increased      mantissa      memory      pixel      Pixel      pixels      resolution      saved      vector   
In a computer that handles real numbers:

the data stored in the are the digits that make up the number and the data stored in the is the power of 2 that the mantissa needs to be raised, to equal the number in its original form before the point was moved.

If the number of bits allocated to the mantissa is then the degree of accuracy of the numbers handled by the computer is decreased.

If the number of bits allocated to the exponent is increased then the range of numbers that the computer can handle is .

If the number of bits allocated to the mantissa is decreased to allow an increase in the bit-allocation to the exponent, the range of numbers handled by the computer will be and their accuracy will be .

is the basic unit of a screen image. A screen image is made up of many , each of which is in the form of a dot and may be black, white or coloured.

Screen is determined by the number of making up a screen image. The size of each and the space between each pixel can vary. Reducing each of these factors means that more make up the screen image, individual are less obvious, and the image is more refined.

A bit-map is the representation of a screen image in the computer's memory. Each is represented by a single in a black and white image, and by a byte or more in a coloured image. The larger the number of on the screen the bigger the bit-map in must be.

In bit-mapped graphics the whole screen is always , pixel by pixel, regardless of whether there are large areas left blank on the screen.

In graphics, each component of a graphic is identified by its , that is its shape, size, its starting point, lengths and colours of its lines, etc.

In amending graphics, the computer can identify from user input what elements of the graphical component have to change but the basic component remains.

Graphics and design artists prefer to work with bit-mapped rather than graphics because they prefer to work at pixel level to show subtle changes in their graphics. For this they need to use bit-mapped graphics. It is not possible to work at pixel level in graphics. For example, a shape can be filled with only one colour or a grading of colour is provided by the computer.