Computer Systems Flashcards
(31 cards)
SVG
Scalable vector graphic
What is a vector graphic?
Vector graphics represent images using shape objects
What may vector graphic shape objects include?
rectangle
ellipse
line
polygon (e.g. pentagon, hexagon)
What attributes may be used to describe the vector graphic shape objects?
co-ordinates
fill colour
line colour
line thickness
x coordinate
y coordinate
What is a bitmapped graphic?
A bit-mapped graphic is stored as a 2D array of pixels
How are bitmapped graphics stored?
Each pixel is stored as a binary value
What is the resolution of a bitmapped graphic?
The resolution of a bit-mapped graphic is its total number of pixels
What is the bit depth of a bitmapped graphic
The bit depth of the image is the number of bits used to store each colour
What are registers and what is their role?
Registers are fast temporary storage locations on the processor
They store data, instructions or addresses being used by the CPU
What the ALU and what is its role?
Arithmetic and Logic Unit
-carries out calculations e.g. adding / subtracting numbers
-compares numbers e.g. 5 > 4
-performs logical operations using AND / OR / NOT
What is the purpose of the control unit?
-manages the flow of data around the computer
-uses a clock to synchronise events
-has a read line which tells memory that data is being read to the processor
-has a write line which tells memory that data is being written from the processor
-has a reset line to reset the contents of the registers
-has an interrupt line which is used to signal that there is an event needing attention
What does RAM stand for ?
Random Access Memory
What is RAM
-a block of storage locations connected to the processor by the data bus and address bus
Each memory location has its own unique address which is used by the address bus to read/write data to the correct place
-used to store data, programs and the operating system
-volatile meaning its contents are cleared when it has no power i.e. the computer is switched off
What are the roles of buses?
They transfer data between the processor and the memory
What is the role of the data bus?
-carries data from memory to be used by the processor
-carries data from the processor to be stored in memory
-is bi-directional because data can travel in both directions
What is the role of the address bus?
-tells memory which memory location is being read from
-tells memory which memory location is being written to
-is uni-directional because the address always goes from the processor to memory
Why are translators required for high level code?
Humans understand high level languages e.g. Python where as computers understand binary
What are the two types of translator?
Interpreter
Compiler
What is an interpreter?
An interpreter translates source code into machine code one line at a time
Advantages of using an interpreter?
Errors are flagged after each line has been interpreted making debugging easier
Disadvantages of using an interpreter.
-Slower because statements in a loop are translated repeatedly
-The interpreter must remain in memory to allow the program to run
What is a compiler?
A compiler translates the entire source code program to object code in one go
Advantages of using a compiler?
-A program only needs to be compiled once, and would only need compiled again if further changes have been made
-The compiler does not need to remain in memory once the program has been compiled, as the object code can run independently
Disadvantages of using a compiler?
Harder to debug because all of the errors are reported once the program has been compiled
