syllabus p1 Flashcards
give one similarity and two differences between ascii and unicode character set
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
state what is meant by sampling rate
the number of samples taken per unit time
explain the effect of increasing the sampling resolution on the sound file
increase number of bits per sample which means that the file size increases
firewall
accept or rejects incoming and outgoing packets based on criteria
pharming
redirects a user to a fake website
anti virus software
scans files on the hard drive for malicious software
encryption
converts to an alternative form
the database is normalized and is in third normal form(3NF)
describe the characteristics of a database that is in third normal form(3NF)
no repeating group of attributes
no partial key dependencies
no non-key dependencies
state what is meant by tuple. give an example of tuple
tuple-a single row in a table
example - a horizontal row on that given table
.state what is meant by the stored program concept in the von neuman model of a computer system.
instructions and date are stored in the same memory space
state the role of the following registers
– program counter (pc)
– index register(iX)
–status register(SR)
–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
which system bus is used in these cpu components
–system clock
–memory address register(MAR)
– control bus
–address bus
describe the purpose of the control unit (cu) in a (cpu)
– to manage the execution of instructions in sequence
–to control the communication between the components of the CPU
describe the purpose of an interrupt in a computer system
to send a signal from a device or process
seeking the attention of the processor
identify two causes of a software interrupt
1)unable to execute program due to missing file
2)division by zero error
state two benefits to a programmer of using dynamic link library (DLL)files
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
describe the ways in which memory management organizes and allocates random access memory
dynamic allocation of RAM to programs
prevents two programs occupying same area of RAM at the same time
describe one appropriate method of compressing a text file
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
explain the reason why increasing the amount of cache memory can improve the performance of a cpu
cache stores frequently used instructions , more cache means more instructions can be transferred faster
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
–usb port
—hdmi port
describe how carrier sense multiple access/collision detection(CSMA/CD) is used in a bus network
–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
explain why these televisions are embedded systems
the embedded system is built into the tv
combination of hardware and software designed for specific function
describe one benefit of using EEPROMS in an embedded system
can be erased and reprogrammed several times
this is so that firmware can be updated
