Representing data Flashcards
How do you convert binary to base 10?
You lay out the byte under the values 128, 64, 32, 16, 8, 4, 2 & 1, and add up the values that are above a 1.
What are the first 5 data values?
byte, kilobyte, megabyte, gigabyte and terabyte.
How many of each value is in the next?
1024 (eg, 1024 megabytes in a kilobyte), except byte, which contains 8 bits.
What is the name of half a byte?
A ‘nibble’ - contains 4 bits.
How do you convert base 10 into binary?
You take away the values 128 to 1 until you have zero.
How do you add binary numbers?
Line them up one above the other. Where there is two zeros, write zero. Where there is a one, write one. Where there is two ones, write zero, carry one.
Say the table of nibbles (probably only a good idea to do this once)
0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111.
How do you convert a byte to hexadecimal?
Split the byte in two and select the correct symbols from the table.
What is the character set of a computer?
All of the characters that the computer can interpret.
What is the difference between ASCII and Unicode?
ASCII only uses 7 or 8 bits, where as Unicode uses 16, meaning that Unicode provides a much larger character set.
What is meta data?
The data stored at the begging of an image or sound file that tells the computer how create the sound or image (sample rate, resolution, height/with, colour depth etc)
What is the color depth?
The amount of bits assigned to each pixel. The more bits per pixel, the more possible colors. (1 bit = two colors, 8 bit = 256 colors etc.)
How do you work out the amount of colors a bit depth can represent?
2^n (eg 16 bit = 2^16 = 65,536 colors.)
What is the problem when storing sound files?
Sounds are analog waves, computers produce digital waves.
What is the sample rate?
The interval between each sample taken to construct the sound wave.
What effect does reducing the sample rate have?
It decreases the file size, but also depletes the quality of the sound.
What is the bit rate?
The amount of bit’s each sample is assigned. This means that the sample value is closer to the actual real life value.
What is bit rate measured in?
Bits per second (amount of data stored for each second of sound), more commonly seen as kbits per second.
What is the accumulator?
A small register in the CPU which contains the results of any current arithmetic calculation (Think back to the LMC)
How are instructions stored?
Each 1 byte instruction contains an Operator and an operand. The operator refers to a operation, such as add, divide, subtract, store, etc, and the Operand represents data. (10011011 - 1001 1011 - ADD 11)
How does the CPU execute an instruction?
It reads the Operator and manipulates whatever is in the accumulator accordingly.
How does the CPU tell the difference between an Operator and an Operand?
It can’t. It just deals with them as it expects them to be ordered (Operator, Operand, Operator, Operand etc).
