system software

Question 1

why operating system should be used

Answer 1

– hardware is unusable without an operating system
– acts as an interface and controls communication between user and hardware.
– provides software platform

Question 2

what are the two types of user interface

Answer 2

command line interface and graphical user interface

Question 3

what is command line interface and describe the purpose of it

Answer 3

– user types in instructions to open or launch a program .
– user is in direct communication with the computer system
– usually a number of instructions are needed to be typed in to open or launch a program

Question 4

what is graphical user interface and describe the purpose of it

Answer 4

– user interacts with the computer system by using icons
– user does not need to know where applications resides within computer
– user launches application by the use of pointer
– windows is the example of G.U.I

Question 5

what are the key management tasks carried out by the operating system

Answer 5

– memory management
– process management
– provision of user interface
– security management task
– file management
– printer management
– interrupt handling
– input output management

Question 5

purpose of memory management

Answer 5

– allocates memory to process
– ensure fair usage of memory
– organize memory by making us of virtual memory
– keeps process separate
– to release memory when a process stop

Question 6

purpose of process management

Answer 6

– manage scheduling of process
– allows multitasking
– handles priorities
– enables process to share information
– prevents interference between the processes
– manages which resource the process- requires

Question 7

purpose of provision of user interface

Answer 7

– allows a user to communicate with hardware by making navigation around the system easier
– provides facilities for user to input data
– provides facilities to show output results to user
– eg:-CLE and GUI

Question 8

purpose of management task

Answer 8

– sets up user account
– access rights
– checks username and passwords
– automatic back-up
– system restore

Question 9

purpose of file management

Answer 9

– storage space divided into file allocation unit
– space allocated for particular files
– maintain directory structure
– specifics logical method of file storage
– provides file naming convention
– controls file access
– specific tasks that can be performed on a file, eg open, delete , copy

Question 10

purpose of printer management

Answer 10

– installs printer driver
– sends data to the printer
– handles error message
– sends commands to the printer

Question 11

purpose of interrupt handling

Answer 11

– identifies priorities to the interrupt
– saves data on power outage
– loads appropriate interrupt service routine

Question 12

purpose input output management

Answer 12

– installation of appropriate drivers
– control access to data being sent
– control access to hardware
– manages communication between devices

Question 13

what is utility software

Answer 13

utility software analyze and maintain a computer system and make it functional

Question 14

name utility softwares

Answer 14

– harddisk formatter
– harddisk defragmenter
– disc content analysis / disk repair
–virus checker
–backup software
– file compression utility

Question 15

purpose of harddisk formatter

Answer 15

– makes existing data inaccessible.
– partition the disk into logical drivers
–prepare the disk for initial use
– might search for error
– sets up specified file system.

Question 16

purpose of harddisk defragmenter

Answer 16

– re-organize the disk
– moves split file so they are contiguous
– creates a large area of contiguous free space

Question 17

purpose of disc content analysis/disk repair

Answer 17

– check for any error
– resolves any errors on the disk
– retrieves files from damaged disk
– marks bad sector of the disk

Question 18

purpose of virus checker

Answer 18

– scans files on a computer for malicious code
– scans files when they enter the system like when memory stick is inserted
– sets up a schedule for virus checking
– delete virus
– regularly updates virus definition

Question 19

purpose backup software

Answer 19

– creates a copy of the content of the disk can be set up to automatically backup
– allows user to decide what is backed up
– allows off site backup
– may encrypt backed up files
– restores the data if necessary

Question 20

purpose of file compression utility

Answer 20

– compress and decompress files
– infrequently used files are compressed
– saves space in harddisk.

Question 21

what is meant by a library routine

Answer 21

– pre existing or pre complied code
– can be linked to other programs
– to perform common complex task

Question 22

benefits of library routine

Answer 22

– less code needs to be written so saves time
– pre tested so reduces testing time
– can be written in different programming languages that enables you to use special features of that language
– can be complex algorithms and no need to work out how to write them
– simplifies the program since just the name of the function is included

Question 23

drawbacks of library

Answer 23

– compatibility issues; may not work with other code
– not guaranteed through testing ; may contain unknown unexpected bags
– the code may not meet exact needs: may give unexpected result

Question 24

what is dynamic link library

Answer 24

– a collection of self- contained shared library program
– that are already compiled
– linked to main program during execution
– library program code is separated from .exe file
– library file only loaded into memory when required at run-time
– a DLL file can be made available to several application at the same time
– if a change is made in DLL code then all of the program that uses DLL will get changed

Question 25

benefits of dynamic link library

Answer 25

– the executable file is smaller
– DLL file only loaded into memory when required at runtime
– changes to DLL code are done independently of the main program so there is no need to recompile the main program
– a single DLL file can be made available to several application saving space space in memory

Question 26

drawbacks of dynamic link library

Answer 26

– the executable code is not self- contained
– the DLL file needed to be included at run time
– appropriate linking software must be available at run time to import the DLL file
– the DLL file should be present or else error
– unexpected changes to DLL could mean the program stop working as expected
– malicious changes to DLL file could install a virus on user’s computer

Question 27

name the language translators

Answer 27

– assembler
– complier
– interpreter

Question 28

describe the purpose of the assembler

Answer 28

programs written in assembly language are translated into machine code by an assembler program. each instruction in the source code consists of an opcode and an operand. the software translates low level language into machine code for the processor to execute. the source code uses instructions from the processors instruction set

Question 29

describe the purpose and the role of compiler

Answer 29

compiler translates high level language into machine code for the processor to execute. compiler creates an executable file . no need to give access to source code go make it more difficult for the user to modify the code

Question 30

benefits of the compiler

Answer 30

– produces an executable file
– user does not have access to source code
– it will probably be faster to run the executable file
– code does not have to complied each time it is executes
– does not need the complier to be present at run- time.

Question 31

drawbacks of compiler

Answer 31

– the source code must be re-compiled every time the programmer changes the program
– find error is difficult as error messages are gives a the end
– the source code must be 100% correct for executable file to be produced

Question 32

describe the purpose and role of interpreter

Answer 32

– interpreter translates high level language into machine code for the processor to execute line by line
– the interpreter reads each statement and checks it before running it
– the interpreter halts when it encounters an error
– the interpreter analysis and checks each line before executing it

Question 33

benefits of interpreter

Answer 33

– errors can be corrected as they occur
– can run a partially complete program when developing
– the effect of any change made to the code can be seen immediately

Question 34

drawbacks of interpreter

Answer 34

– no executable file is produced
– user has access to source code
– need to translate the source code again and again so consumes times
– interpreter should be present at the time of execution

Question 35

differences between compiler and interpreter

Answer 35

*compilers create an executable file
– interpreter does not creates executable file

*the compiled program can be independently distributed

-interpreter executes each statement immediately after decoding
*compilers checks the whole program for errors

• the interpreter software must be present in main memory every time the program is executed
• the compiled program does not require compiler

– cross complication is possible (compile on one hardware to run on another)

Question 36

what are the features of an IDE

Answer 36

– pretty printing
– automatic indentation
– syntax checking
– highlights any undeclared variables
– type checking

Question 37

what are the features provides by an IDE that assist in “initial error detection”

Answer 37

– dynamic syntax checking
– type checking
– identification of unused variable

Question 38

debugging tools that IDE can provide

Answer 38

– breakpoint: run the code to set point to find errors
– report window: errors are displayed in a separate window in IDE
– single stepping : execute the code line by line
– variable watch : checks the content of variable at specific points