computer organisation Flashcards
explain the machine instruction cycle
thats when a computer fetches the instruction from its memory and then executes it
first step in the fetch-execute cycle is fetching the instruction.
the CPU fetches this from the main memory (RAM) and stores
it in the CPU temporary memory, called the registers.
second step is decoding the instruction - CPU has codes like policemen do for what to do with the data.
explain it more detailed(the fetch execute computer cycle)
- fetch:
PC -> MAR (the adress of the next instruction is copied onto the MAR from PC) -> RAM -> (data is fetched using the address from MAR and sent to the MDR) MDR -> CIR (the instruction is stored in the MDR which is the copied into the CIR) -> - decode & execute:
CU (the instructions are then sent to the CU which makes changes to the ALU, ALU then executes the instruction nd stores it in the accumulator if needed.) -> - store:
Accumulator (stores the results of the executed instruction)
from where to where is the address bus?
from MAR to Memory
from where to where is the data bus?
from ALU or memory to the Instruction decoder
what are the features of the memory in CPU
no permanent (only registers)
RAM features?
volatile
what is primary storage?
cache and RAM
whats the secondary storage?
hard drive
what is offline storage?
CD-RW (cede)
USB thumb drive
tape drive
whats the hierarchy of operating system?
under all software there are application (7 types but never mentioned which ones so I assumed that that wont be on the test) software and system software (operating system, utilities, drivers and libraries)
what are the functions of an operating system
provides a user interface
does memory management
does peripheral management
allows multi-tasking
provides security
present user interface
(OS provides) a link between the user and the computer hardware
some types of user interfaces:
- graphical User Interfaces (GUIs) that have menus and icons,
- command Line Interfaces (CLIs) where the user types in codes,
- natural Language Interface (NLIs) where the user speaks to the
interface
- menu Based Interface (MBIs) which gives the user a selection of
options.
I ADVICE YOU TO GOOGLE EACH AND MAKE A SCETCH OF IT
present memory management
keeping track of storage divices like HDD and controlling which application has access to which area of memory (RAM)
each location in memory can be read, modified, and written to by the OS, when the memory location is full the OS sends a confirmation message. similarly, the OS provides file management services by sorting out where data is stored on the disk drives and memory.
The OS allows users to organise files in folders as well as to copy and delete files.
examples are file manager or finder on mac and memory manager
present peripheral management
keyboard, mouse, monitor and printers are controlled through device drivers.
a device driver is a software program which allows hardware devices to be used by the OS. They act as translators between the devices and the computer system.
example would printing
present multitasking
the OS coordinates the working of different programs by allocating the CPU time between different programs based on time and priority of the software application.
each task running is given a slice of time, or a turn on the CPU.
each task has to wait its turn unless it
is given a higher priority by the OS in which case it gets more or longer time slices.
exmple - threads (111222333) getting intertwined so that theyre in an even order (123123123) in the scheduler and then cpu deals with them in that order (so tehyre all dealt with at the same time)
present security
usernames and passwords
examples
logining
recap. list functions of the os
provides a user interface
does memory management
does peripheral management
allows multi-tasking
provides security
outline the use of a range of applications software
what are the common application softwares
word processors (programm for storing and managing plain text)
spreadsheets (same but with tables)
database management systems (DBMS)
email clients (programme to manage email but not like website)
web browsers
computer aided design (CAD)
graphic processing software
what are the common features of applications
toolbars, menus, dialogue boxes and GUI components
give me an example of certain parts of the interface that are provided by libraries in the OS and certain parts that are specific to each application
the menu bar and buttons are standard, but
the specifics/pictures are up to the individual application
whats a bit
0 or 1
whats a byte
eight bits
whats a binary
two values possible
whats a denary
ten values possible
whats a hexadecimal
16 values possible
what are the four general ways that the data may be represented in
a string
a number
a character
hex (colour code)
difference between ascii and unicode
ascii (XXXX XXXX) only can represent 128 characters and unicode can like 143000 (XXXX XXXX XXXX XXXX)
