Christmas assessment 2017 Flashcards
state five different scheduling algorithms
- first come first served
- round robin
- shortest job first
- shortest remaining time
- multilevel feed back queues
what is the propose of scheduling?
- to make the most efficient use of the processor
- to be fair to all applications
- to provide a reasonable response time
- prevent processes from failing to run/deadlock/starvation.
what is paging?
- splitting parts of a program into equal sized pieces
- uses physical divisions
what is segmentation?
-splitting parts of a program into unequal sized pieces
what are the similaritys of paging and segmentation?
- both are ways of splitting up memory
- both use virtual memory to swap parts of programs
- allows programs that are larger than memory to run
- allows programs to be stored in memory non contiguosly
explain the fetch-decode-execute cycle.
fetch- the next instruction is fetched from main memory
decode- the instructions are translated/ split into opcode and operand
execute- the opcode is carried out on the operand
what are the registers that are used in the Von Neumann architecture?
- program counter
- memory address register
- memory data register
- current instruction register
- accumulator
- index register
- interrupt register
- memory buffer register
features of cisc
- cisc is more complex
- cisc has a longer instruction set
- cisc had many address modes
- cisc may have more registers
- cisc takes many cycles to complete one instruction
- cisc has a varable number of bytes
features of risc
- risc is simpler
- risc has a shorter instruction set
- risc request more ram
- risc takes one machine cycle to complete one instruction
- risc has a fixed number of bytes
what are the three basic programming constructs?
iteration- FOR, WHILE, REPEAT UNTIL
selection- IF,SWITCH,CASE,SELECT
sequence- line 1, line 2, line 3
what is abstraction?
abstraction is the process of separating ideas from reality this is a means of hiding detail and only using relevant information it is a representation of reality showing important features and excluding irreverent ones
how can programmers use re-usable components?
software is modular for example objects and functions. modules can be transplanted into new software or can be shared through the use of program libraries
explain two advantages of re-using components.
modules are already tested so programs are more reliable.
less development time as programs can be shorter and modules can be shared.
what is an identifier?
a name or symbol given to a variable/subroutine.
what is +?
a concatenation operator
