this stands for Radio Frequency Identification Key
this can be used for unlocking car doors
the tag is the transponder and the reader transmits the signal
the signal activates the RFID transmitter (tag)
how it works:
antenna sends radio wave signal and the transponder receives the radio waves and induces an electrical current and sends the response to the reader via radio waves
no physical connection is needed
the tag must be near the reader
Sunday, 5 March 2017
Sunday, 12 February 2017
files in programming
to create a new file:
dim aLine as string
fileopen(1, "Diary2.txt", openmode.output)
console.writeline
aLine = console.readline
Printline(1,aLine)
fileclose(1)
to read a file:
dim NextLine as string
fileopen(1, "diary.txt" , openmode input)
console.writeline
do wile not EOF(1)
next line lineinput(1)
console.writeline(NextLine)
loop
fileclose(1)
to append a file (add onto a file)
dim aLine as string
fileopen(1, "Diary2.txt", openmode.append)
console.writeline
aLine = console.readline
Printline(1,aLine)
fileclose(1)
dim aLine as string
fileopen(1, "Diary2.txt", openmode.output)
console.writeline
aLine = console.readline
Printline(1,aLine)
fileclose(1)
to read a file:
dim NextLine as string
fileopen(1, "diary.txt" , openmode input)
console.writeline
do wile not EOF(1)
next line lineinput(1)
console.writeline(NextLine)
loop
fileclose(1)
to append a file (add onto a file)
dim aLine as string
fileopen(1, "Diary2.txt", openmode.append)
console.writeline
aLine = console.readline
Printline(1,aLine)
fileclose(1)
different translators
assembler
compiler
- translates assembly language program into machine code
compiler
- takes source code of a high level language and translates into object code
- looks at the entire source code to translate and optimize the instructions
- the compiler will produce object code that can be distributed to people who do not need the development environment to execute the code.
interpreter
- an interpreter analyses and executes source code line by line
- as each statement is analysed, the interpreter calls routines to carry out each instruction
software
software can be split into two different software's
application software
system software
system software covers 4 things
operating system:
manages the computer hardware
manages secondary storage
manages I/O devices
designed to act as an interface between user and computer.
manages the operation of the computer
links hardware application and uses virtual machine
library programs (DLL):
dynamic link library
carry out common tasks
critical for applications
will contain code, data resources
control dialogue boxes
mange memory display text and graphics
translator software:
compiler
assembler
interpreter
used by programmers to convert by one program to another
the CPU doesn't understand the programmers code, has to be translated into machine code of 1's and 0's
utility software:
to ensure the computer is running efficiently often supplied with the operating system
disk formatting tool
RAM- random access memory- volatile
ROM- read only memory- non-volatile
an operating system manages:
hardware to allocate processes
main memory
I/O devices
secondary storage
Virtual machines: the purpose is that the complexities of how tasks are done are hidden away from the user
application software
system software
system software covers 4 things
operating system:
manages the computer hardware
manages secondary storage
manages I/O devices
designed to act as an interface between user and computer.
manages the operation of the computer
links hardware application and uses virtual machine
library programs (DLL):
dynamic link library
carry out common tasks
critical for applications
will contain code, data resources
control dialogue boxes
mange memory display text and graphics
translator software:
compiler
assembler
interpreter
used by programmers to convert by one program to another
the CPU doesn't understand the programmers code, has to be translated into machine code of 1's and 0's
utility software:
to ensure the computer is running efficiently often supplied with the operating system
disk formatting tool
RAM- random access memory- volatile
ROM- read only memory- non-volatile
an operating system manages:
hardware to allocate processes
main memory
I/O devices
secondary storage
Virtual machines: the purpose is that the complexities of how tasks are done are hidden away from the user
Thursday, 19 January 2017
January Mock corrections
1a) a system stores integers in 16 buts. using binary representation, show the steps of subtracting 6 from 18, using two's compliment.
18= 0000000000010010
6= 0000000000000110
-6= 11111111111111001
1
1111111111111010
0000000000010010
12= 000000000000110
1b) A801= 1010100000000010
1.01010000000 0010
decimal value = -2.75
2a) smallest positive value
0.1000000 0001
3c) calculate the number of bytes
10 x 10 = 100
100 x 2 = 200
200 / 9 = 25 bytes
5b) if an image required 3000 colours - how many bits would be required for the colour depth?
12 bits
18= 0000000000010010
6= 0000000000000110
-6= 11111111111111001
1
1111111111111010
0000000000010010
12= 000000000000110
1b) A801= 1010100000000010
1.01010000000 0010
decimal value = -2.75
2a) smallest positive value
0.1000000 0001
3c) calculate the number of bytes
10 x 10 = 100
100 x 2 = 200
200 / 9 = 25 bytes
5b) if an image required 3000 colours - how many bits would be required for the colour depth?
12 bits
Sunday, 15 January 2017
logic gates
there are 6 different logic gates:
AND gate
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A
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B
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A.B
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0
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0
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0
|
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0
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1
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0
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1
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0
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0
|
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1
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1
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1
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The AND gate is an electronic
circuit that gives a high output (1)
only if all its inputs are high
OR gate
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A
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B
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A+B
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0
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0
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0
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0
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1
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1
|
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1
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0
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1
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1
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1
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1
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The OR gate is an electronic
circuit that gives a high output (1) if one
or more of its inputs are high.
NOT gate
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A
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 |
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1
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0
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0
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1
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The NOT gate is and electronic circuit that produces an
inverted version of the input at its output. It is also know as an inverter. If the input variable is A,
the inverted output is NOT A.
NAND
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A
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B
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 |
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0
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0
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1
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0
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1
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1
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1
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0
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1
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1
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1
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0
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This is a NOT-AND gate which is equal to an AND gate followed
by a not gate. The outputs of all NAND gates are high if any of the inputs are low
NOR gate
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A
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B
|
 |
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0
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0
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1
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0
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1
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1
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1
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0
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1
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1
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1
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0
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This is a NOT-OR gate which is equal to an OR gate followed
by a NOT gate. The outputs of all NOR gates are low if any of the inputs are high.
EXOR gate
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A
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B
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 A+B |
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0
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0
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0
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0
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1
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1
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1
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0
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1
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1
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1
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0
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the “Exclusive-OR”
gate is a circuit which will give a high output if either, but not both, of its two inputs are high.
Tuesday, 10 January 2017
Bubble sort algorithm
Bubble sort is a simple algorithm that compares based in which each pair of adjacent elements is compared. the values are then swapped when they are not in order. However this is not suitable for large sets of data as it is not a quick method for sorting.
Algorithm
for all elements of the list
if list(i) > list(i + 1)
swap(list(i) = list(i + 1))
end if
end for
return list
end bubble sort
Pseudo-code
repeat
swapped = false
for i = 1 to array - 1 do
if A(i) > A(i + 1) then
temp = A(i)
swap A(i) = A(i + 1)
A(i + 1) = temp
swapped = true
end if
Code
Module Module1
'Callum Westcott
'These are my variables
Dim swap As Boolean
Dim num(8) As Integer
Dim temp As Integer
Sub Main()
'these are the values for the array
num(1) = 20
num(2) = 72
num(3) = 69
num(4) = 88
num(5) = 42
num(6) = 169
num(7) = 101
num(8) = 99
'this do loop will make sure that all of the number will show in order
Do
swap = False
For index = 1 To 8 - 1
If num(index) > num(index + 1) Then
temp = num(index)
num(index) = num(index + 1)
num(index + 1) = temp
swap = True
End If
Next
Loop Until swap = False
'this will display the ordered array
For index = 1 To 8
Console.WriteLine(num(index))
Next
Console.ReadLine()
End Sub
End Module
Algorithm
for all elements of the list
if list(i) > list(i + 1)
swap(list(i) = list(i + 1))
end if
end for
return list
end bubble sort
Pseudo-code
repeat
swapped = false
for i = 1 to array - 1 do
if A(i) > A(i + 1) then
temp = A(i)
swap A(i) = A(i + 1)
A(i + 1) = temp
swapped = true
end if
Code
Module Module1
'Callum Westcott
'These are my variables
Dim swap As Boolean
Dim num(8) As Integer
Dim temp As Integer
Sub Main()
'these are the values for the array
num(1) = 20
num(2) = 72
num(3) = 69
num(4) = 88
num(5) = 42
num(6) = 169
num(7) = 101
num(8) = 99
'this do loop will make sure that all of the number will show in order
Do
swap = False
For index = 1 To 8 - 1
If num(index) > num(index + 1) Then
temp = num(index)
num(index) = num(index + 1)
num(index + 1) = temp
swap = True
End If
Next
Loop Until swap = False
'this will display the ordered array
For index = 1 To 8
Console.WriteLine(num(index))
Next
Console.ReadLine()
End Sub
End Module
Sunday, 4 December 2016
representing images, sound and other data
5a) a bitmap image has resolution 1000 x 400. Calculate the resolution in megapixels.
1000 x 400 = 400,000
B) Each pixel in the image is stored using 16 bits. Calculate the file size in bytes in bytes.
400,000 x 16 = 6,400,000
6,400,000 / 8= 800,000
6a) a bitmap image resolution 2000 x 5000 uses 400 distinct colours. Calculate the size of the file in megabytes /mebibytes
2000x x 5000 = 10,000,000
log(400) / log(2) = 9
10,000,000 x 9 = 90,000,000
90,000,000 / 8 / 1024 / 1024 = 10.7 MiB
B) the image's resolution is increased to 5000 x 5000. Calculate the increase in file size from part a in megabytes to one decimal place / mebibytes
16.1 Mib increase
C) calculate the change in file size from part b if the number if colours is increased to:
i 500
2.2 MiB
1000 x 400 = 400,000
B) Each pixel in the image is stored using 16 bits. Calculate the file size in bytes in bytes.
400,000 x 16 = 6,400,000
6,400,000 / 8= 800,000
6a) a bitmap image resolution 2000 x 5000 uses 400 distinct colours. Calculate the size of the file in megabytes /mebibytes
2000x x 5000 = 10,000,000
log(400) / log(2) = 9
10,000,000 x 9 = 90,000,000
90,000,000 / 8 / 1024 / 1024 = 10.7 MiB
B) the image's resolution is increased to 5000 x 5000. Calculate the increase in file size from part a in megabytes to one decimal place / mebibytes
16.1 Mib increase
C) calculate the change in file size from part b if the number if colours is increased to:
i 500
2.2 MiB
glossary
Glossary
Absolute Error - difference between true resultant value and nearest representable value
ADC (Analogue-to-digital converter) - to sample electrical equivalent of sound and convert sample into digital signal using two voltage levels
Algorithm - a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer.
ADC (Analogue-to-digital converter) - to sample electrical equivalent of sound and convert sample into digital signal using two voltage levels
Algorithm - a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer.
Analogue Data - data that varies in a continuous manner
Assignment - storing data into a variable, giving that data a memory location
Bitmap - defines a display space and the colour for each pixel or "bit" in the display space
Bits - the smallest unit of data in a computer, has a single binary value: 0 or 1
Bytes - 2nd smallest unit of data, 8 bits or 2 nibbles
Compression - process of reducing the number of bits required to represent data
Bitmap - defines a display space and the colour for each pixel or "bit" in the display space
Bits - the smallest unit of data in a computer, has a single binary value: 0 or 1
Bytes - 2nd smallest unit of data, 8 bits or 2 nibbles
Compression - process of reducing the number of bits required to represent data
DAC (Digital-to-analogue converter) - to playback recorded sound
Even Parity - a parity checking mode in which an extra bit, called a parity bit, is set to 1 if there is an even number of 'one' bits in a one-byte data item.
Hz (Hertz) - unit of frequency (used to measure wave frequencies, such as sound waves)
Even Parity - a parity checking mode in which an extra bit, called a parity bit, is set to 1 if there is an even number of 'one' bits in a one-byte data item.
Hz (Hertz) - unit of frequency (used to measure wave frequencies, such as sound waves)
Iteration - also known as looping; process where a set of instructions are repeated until a condition is met
Nyquists Theorem - "sound must be sampled twice its highest analogue frequency in order to extract all of the information from the bandwidth and accurately represent original acoustic energy"
Odd Parity - a parity checking mode in which an extra bit, called a parity bit, is set to 1 if there is an odd number of 'one' bits in a one-byte data item.
Overflow - where the value is too large to be represented using the available number of bits
Pixel - the smallest representable element of an image that can be individually processed
Precision - maximum number of significant digits that can be represented
Pseudocode - a notation resembling a simplified programming language, used in program design
PCM (Pulse-code modulation) - a method used to digitally represent sampled analog signals
Relative Error - absolute error divided by the true resultant value
Resolution - the number of pixels within an image, expressed in terms of horizontal x vertical axis
Odd Parity - a parity checking mode in which an extra bit, called a parity bit, is set to 1 if there is an odd number of 'one' bits in a one-byte data item.
Overflow - where the value is too large to be represented using the available number of bits
Pixel - the smallest representable element of an image that can be individually processed
Precision - maximum number of significant digits that can be represented
Pseudocode - a notation resembling a simplified programming language, used in program design
PCM (Pulse-code modulation) - a method used to digitally represent sampled analog signals
Relative Error - absolute error divided by the true resultant value
Resolution - the number of pixels within an image, expressed in terms of horizontal x vertical axis
Selection - also called decision; program takes course of action depending on the answer e.g. if statement.
Sequence - where an action or event leads to the next ordered action in a predetermined order
Underflow - where the value is too small to be represented using the available number of bits
Vector - co-ordinate based image that does not have a reduction in clarity when zoom is increased or decreased
Bubble Sort- a simple algorithm that compares based off each pair.
Sunday, 20 November 2016
Arrays
when storing a single number you would have declare one integer (Short) variable
to store 3 numbers you would need three variables
an array is a data structure that stores many items using a single variable
a single variable stores one single data item
an array is like lots of boxes held together
Dim numbers(4) as integer
Dim sNames(5) as string
the number in the brakets indicated the size of the array. We always start from zero
Exam marks(0) = console.readline
Exam marks(1) = console.readline
Exam marks(2) = console.readline
Exam marks(3) = console.readline
Exam marks(4) = console.readline
for Index = 0 to 4
console.writeline(ExamMarks(Index))
Next Index
the above section of code will print out every time in the array
array processings makes use of for loops
how to enter into an array
for Index = 0 to 4
console.writeline("Enter exam mark numbers" & Index)
ExamMarks(Index) = console.readline
Next Index
to store 3 numbers you would need three variables
an array is a data structure that stores many items using a single variable
a single variable stores one single data item
an array is like lots of boxes held together
Dim numbers(4) as integer
Dim sNames(5) as string
the number in the brakets indicated the size of the array. We always start from zero
Exam marks(0) = console.readline
Exam marks(1) = console.readline
Exam marks(2) = console.readline
Exam marks(3) = console.readline
Exam marks(4) = console.readline
for Index = 0 to 4
console.writeline(ExamMarks(Index))
Next Index
the above section of code will print out every time in the array
array processings makes use of for loops
how to enter into an array
for Index = 0 to 4
console.writeline("Enter exam mark numbers" & Index)
ExamMarks(Index) = console.readline
Next Index
Representing sound in a computer
analogue data that varies in a continuous matter
analogue-to-digital converter (ADC): to sample electrical equivalent of sound and convert sample into digital signal using two voltage level
to playback recorded sound, use of digital to analogue can vector (DAC)
PCM: form of an analogue signal is produced by an ADC
PAM: pulse aptitude modulation
formula to calculate file size:
file size = sample rate(Hz) x length of recording (seconds) x sampling resolution (Bits)
example
44,000 Hz x 60 seconds x 16 bits = 42,240,000 bits = 5,280,000 bytes
or 5.28 MB or 5.03 MiB
Nyquist's theorem
sound must be sampled at least twice its highest analogue frequency in order to extract all of information from the bandwidth and accurately represent original acoustic energy.
analogue-to-digital converter (ADC): to sample electrical equivalent of sound and convert sample into digital signal using two voltage level
to playback recorded sound, use of digital to analogue can vector (DAC)
PCM: form of an analogue signal is produced by an ADC
PAM: pulse aptitude modulation
formula to calculate file size:
file size = sample rate(Hz) x length of recording (seconds) x sampling resolution (Bits)
example
44,000 Hz x 60 seconds x 16 bits = 42,240,000 bits = 5,280,000 bytes
or 5.28 MB or 5.03 MiB
Nyquist's theorem
sound must be sampled at least twice its highest analogue frequency in order to extract all of information from the bandwidth and accurately represent original acoustic energy.
Data Compression
some data files are quite large high resolution or music sampled data high frequency result in several megabytes of data.
compression- process pf reducing the number of bits required to represent data
lossless: often used where the graphic might be changed by another person or where the image contains layers of graphics that need to be kept separate from each other.
no data loss
it is high quality
lossy: offers a higher compression on rotation
run length encoding: a method of compressing data by eliminating repeated data
dictionary based: compression technique is used whem compressing text files
compression- process pf reducing the number of bits required to represent data
lossless: often used where the graphic might be changed by another person or where the image contains layers of graphics that need to be kept separate from each other.
no data loss
it is high quality
lossy: offers a higher compression on rotation
run length encoding: a method of compressing data by eliminating repeated data
dictionary based: compression technique is used whem compressing text files
For loops
For Loops
for loops are used when you know exactly how many times the code must be repeated
this is an example of for loops working, it shows all the values from one number to another.
Sunday, 6 November 2016
Bit Mapped Graphics
pixel: the smallest addressable area of an image
resolution: the number of pixels per unit of measurement
the resolution of an image or VDU screen is expressed as the number of pixels per column
E.g 1024 x 768 = 817,152
Bit mapped graphics
the colour of each pixel is stored as a binary pattern in video memory in a monochrome screen (two colours) Just 1 bit will be needed for each pixel.
0 for white and 1 for black
if 2 bits are used for each pixel then four colours can be stored, for example :
00 - white
01 - blue
10 - red
11 - black
Colour Depth
the colour depth is the number of bits used to re-pressure a single pixel.
if 8 colours was waned then 3 bits would be needed
2 to the power of 3 = 8
2 to the power of 4 = 16
2 to the power of 8 = 256
Bytes required per pixel?
if 16 colours are wanted then we would use 4 bits per pixel
in bytes this would be 1/2 a byte
if 256 colours are wanted then we would use 8 bits per pixel
there would be 1 byte allocated to each pixel
formula for bits in a pixel, if you have N bits, you can store 2^N different colour codes.
Vector
co-ordinates of images are stored as mathematical data.
points are described by relative distance from the origin
objects can be scaled and grouped together by its features
resolution: the number of pixels per unit of measurement
the resolution of an image or VDU screen is expressed as the number of pixels per column
E.g 1024 x 768 = 817,152
Bit mapped graphics
the colour of each pixel is stored as a binary pattern in video memory in a monochrome screen (two colours) Just 1 bit will be needed for each pixel.
0 for white and 1 for black
if 2 bits are used for each pixel then four colours can be stored, for example :
00 - white
01 - blue
10 - red
11 - black
Colour Depth
the colour depth is the number of bits used to re-pressure a single pixel.
if 8 colours was waned then 3 bits would be needed
2 to the power of 3 = 8
2 to the power of 4 = 16
2 to the power of 8 = 256
Bytes required per pixel?
if 16 colours are wanted then we would use 4 bits per pixel
in bytes this would be 1/2 a byte
if 256 colours are wanted then we would use 8 bits per pixel
there would be 1 byte allocated to each pixel
formula for bits in a pixel, if you have N bits, you can store 2^N different colour codes.
Vector
co-ordinates of images are stored as mathematical data.
points are described by relative distance from the origin
objects can be scaled and grouped together by its features
Tuesday, 1 November 2016
Bits, Bytes and nibble
Nibble = 4 bits
2x nibble = 1 byte (8 bits)
Kb = Kilobit = 1000 bits = 125 bytes
Mb = Megabit = 1000 Kb
KB = Kilobyte = 10^3 = 1,000
MB = Megabyte = 10^6 = 1,000,000
GB = Gigabyte = 10^9 = 1,000,000,000
TB = Terabyte = 10^12 = 1000 GB
Ki = Kibibyte = 2^10 = 1024 bytes
Mi = Mebibyte = 2^20 = 1,048,576
Gi = Gibibyte = 2^30 = 1024 Mi
Ti = Tebibyte = 2^40 = 1024 Gi
2x nibble = 1 byte (8 bits)
Kb = Kilobit = 1000 bits = 125 bytes
Mb = Megabit = 1000 Kb
KB = Kilobyte = 10^3 = 1,000
MB = Megabyte = 10^6 = 1,000,000
GB = Gigabyte = 10^9 = 1,000,000,000
TB = Terabyte = 10^12 = 1000 GB
Ki = Kibibyte = 2^10 = 1024 bytes
Mi = Mebibyte = 2^20 = 1,048,576
Gi = Gibibyte = 2^30 = 1024 Mi
Ti = Tebibyte = 2^40 = 1024 Gi
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