syllabus p1

Question 1

give one similarity and two differences between ascii and unicode character set

Answer 1

similarity -they both represent each character using unique code

difference1-unicode can go up to 32 bits per character whereas ASCII is 7 or 8 bits. unicode can represent a wider range of characters then ASCII.

difference2-different languages are represented using unicode whereas ASCII is only for one language

Question 2

state what is meant by sampling rate

Answer 2

the number of samples taken per unit time

Question 3

explain the effect of increasing the sampling resolution on the sound file

Answer 3

increase number of bits per sample which means that the file size increases

Question 4

firewall

Answer 4

accept or rejects incoming and outgoing packets based on criteria

Question 5

pharming

Answer 5

redirects a user to a fake website

Question 6

anti virus software

Answer 6

scans files on the hard drive for malicious software

Question 7

encryption

Answer 7

converts to an alternative form

Question 8

the database is normalized and is in third normal form(3NF)
describe the characteristics of a database that is in third normal form(3NF)

Answer 8

no repeating group of attributes
no partial key dependencies
no non-key dependencies

Question 9

state what is meant by tuple. give an example of tuple

Answer 9

tuple-a single row in a table
example - a horizontal row on that given table

Question 10

.state what is meant by the stored program concept in the von neuman model of a computer system.

Answer 10

instructions and date are stored in the same memory space

Question 11

state the role of the following registers
– program counter (pc)
– index register(iX)
–status register(SR)

Answer 11

–pc stores the address of the next instruction to be fetched
–IX to store a value that is added to an address to give another address
–SR to store flags which are set by events

Question 12

which system bus is used in these cpu components
–system clock
–memory address register(MAR)

Answer 12

– control bus
–address bus

Question 13

describe the purpose of the control unit (cu) in a (cpu)

Answer 13

– to manage the execution of instructions in sequence
–to control the communication between the components of the CPU

Question 14

describe the purpose of an interrupt in a computer system

Answer 14

to send a signal from a device or process
seeking the attention of the processor

Question 15

identify two causes of a software interrupt

Answer 15

1)unable to execute program due to missing file
2)division by zero error

Question 16

state two benefits to a programmer of using dynamic link library (DLL)files

Answer 16

1)no need to recompile the main program when changes are made to DLL because changes to DLL file code are done independently of the main program

2)executable file size is smaller because the executable does not contain all library routines

Question 17

describe the ways in which memory management organizes and allocates random access memory

Answer 17

dynamic allocation of RAM to programs
prevents two programs occupying same area of RAM at the same time

Question 18

describe one appropriate method of compressing a text file

Answer 18

lossless compression using run length encoding ,whereby repeated sequences of characters are replaced by a single copy of the character and a counter of the number of characters

Question 19

explain the reason why increasing the amount of cache memory can improve the performance of a cpu

Answer 19

cache stores frequently used instructions , more cache means more instructions can be transferred faster

Question 20

state the name of the pheripheral device port that provides a physical connecter in the computer for each of there pheripheral devices
–3D PRINTER
–MONITOR

Answer 20

–usb port
—hdmi port

Question 21

describe how carrier sense multiple access/collision detection(CSMA/CD) is used in a bus network

Answer 21

–before transmitting , a device checks if the channel is busy and date will be sent when the channel is free
– since there is usually more than one computer connected to same transmission medium , two workstations can start transmit at the same time causing a collision
–if collision is detected , the workstations send a jamming signal and abort transmission
–each of them will wait for a random amount of time before attempting to resend

Question 22

explain why these televisions are embedded systems

Answer 22

the embedded system is built into the tv
combination of hardware and software designed for specific function

Question 23

describe one benefit of using EEPROMS in an embedded system

Answer 23

can be erased and reprogrammed several times
this is so that firmware can be updated