Author: Mr Stratton

Computing teacher and a PT at Coltness High School.

N5 – Technical implementation (storage)

Comparison of local versus cloud storage  
Since the contents of RAM is lost when power is disconnected it needs to be stored, so it can be used latter.

Local storage is used to store the information on the computer, such as a hard drive or flash drive.

Cloud storage, stores the information on the Internet where it can downloaded and used later.
Comparison of built-in versus portable storage  
Built in storage is fixed inside the computer and cannot be removed. This is normally a Hard Drive or Solid State Drive.

Portable storage can be moved between computer systems, to allow data to be transferred. E.g. Optical Disc, portable hard drive or flash drive.
Comparison of different interface types and their data transfer speeds including:  
Firewire  
This is a wired interface that can connect a device to the computer at speeds of up to 800Mbps. This is often used for portable hard drives or digital video cameras. Devices can be daisy chained together so that up to 63 peripherals can be connected.
USB  
Universal Serial Bus is a wired interface that can connect a device to a computer at speeds of up to 7.2Gbps. A USB hub is used to connect many devices together up to 127 devices can be connected together. Many different devices can be connected via USB including Keyboards, flash drives and mobile phones.
Bandwidth  
Bandwidth is the amount the data that can transferred in a fixed amount of time. This is often expressed in bits per second (bps). A high bandwidth connection is often referred to as broadband.
Description of different types of storage devices and their media in terms of functionality, speed and capacity (in appropriate units) including:  
magnetic  
Hard disk drives are an example of magnetic storage. These random access devices are used to store large amounts of data, 10TB disks are available. Although they can be portable, they are quite fragile and need to be handled with care.
optical  
CDs, DVDs & Blu-Ray are example of optical storage. The information is stored on a disc and read using a laser. The discs are portable but the drives themselves are very sensitive to vibration and can only be used in fixed location. Optical discs can store up to 50GB on one disc.
rewritable, read-only  
Optical discs are available in many configuration and are often suffixed with;

-ROM – Can only be read and not written to.

-R – Is a recordable disc which can be written to once and read many times

-RW – ReWritable discs can be written to many times
solid state  
A solid-state drives have the fastest access and transfer times of any storage device. SSDs are portable in the form of flash drives and are very robust. They are however quite expensive and cannot currently store as much as a hard drive.
Description and exemplification of the appropriate type of storage required for a specific information system including: type of device, capacity & interface type  
Server Based
Servers require fast, cheap storage with a large capacity. As a result, Hard Disk Drives are used. This allows the most amount of storage with the cheapest cost.
Backup
Optical Discs are often used to backup information. As these discs, can be stored securely in a different place from the computer.
On the move
Solid State Flash Drives are very portable with a large storage capacity. These are robust and not susceptible to damage from vibration.

N5 – Technical Implementation (hardware requirements)

Description and exemplification of the appropriate type of hardware required for a specific information system including:
input and output devices
A device which is used to enter information in to a computer system is called a input device. E.g. Keyboard, microphone, mouse, etc.

A device which the processor can send data to or display data on is an output device. E.g. Speakers, monitor, printer, projector, etc.

Some devices are both input and output devices. Touch screen, rumble controller.
processor type and speed (Hz)
Some processors are better suited to certain tasks. So a processor that uses less power might be better suited for a mobile phone or laptop.

In general, the faster the processor the more power it requires, so mobile processors often run a slow speed to desktop processors.
memory (RAM, ROM)
The more memory a computer has the more things it can do at the same time.

More memory requires more power, so mobile computers often have less RAM and ROM than desktop computers.
memory capacity (RAM)
Computer memory is measure in GB. Often computers don’t have the maximum amount of memory installed, this is often due to the costs involved.

N5 – Low-level operations and computer architecture

Explanation of the need to translate high-level program code to binary (machine code).  
Computers can only understand binary code, therefore all human readable programming codes have to be translated into binary. Binary code which contains machine specific instructions is called machine code. A machine code file will only work on the computer type it was created for. Therefore one program does not work on different systems (X Box and Play Station)
Comparison of interpreters and compilers.  
Interpreters – These are resident in the computer’s memory when the program is executed. These translate the source code (program) one line at a time into machine code, this can make them appear slow. Syntax errors are often highlighted as they are made.

Compilers – These translate the source code into machine code, this machine code can then be saved and executed without further need for the compiler. Making the program appear to execute faster than the interpreted version. Syntax errors are only apparent at run time.
Description and exemplification of the use of binary to represent positive integers.  
Binary is a base 2 numbering systems where every digit can have two values ( 0 / 1 )

This is because computers can only represent information using electricity which is either on (1) or off (0)
Conversion from Binary to decimal and vice-versa.  
To convert a decimal number to a binary number, we need to start at 1 and double it.

128 64 32 16 8 4 2 1
0 0 1 0 1 0 1 0

So the number above is 42 ( 32+8+2)
Description of floating point representation of real numbers using the terms mantissa and exponent.  
Binary can only store a whole number so to store a real number we use floating point notation. MxBe. The Base is 2 for binary.

The Mantissa stores the number itself and therefore controlling the accuracy.

The Exponent store the magnitude of the number and therefore controls the range.

Mantissa Range Exponent Accuracy (MARE)
Description of ASCII code (7-bit) used to represent characters.  
American Standard Code for Information Interchange.

Every letter is given a number (A = 65) this is then stored as binary. This allows us to store 128 different symbols and commands, this allows for messages and documents to be read by different computer systems. The 1st 32 numbers are reserved for non-printing characters, such as TAB and RETURN.
Description of the vector graphics method of graphic representation.  
Vector Graphics store pictures as a series of objects and their attributes.

To draw a red circle we would need a circle object and then describe it with attributes.

<circle cx=”50″ cy=”50″ r=”40″ stroke=”black” stroke-width=”3″ fill=”red” />

This is very useful for storing non-photographic work as it can be scaled up without losing quality.
Description of the bit-mapped method of graphics representation.  
Bitmap graphics store images as a grid of pixels (Picture Elements). These pixels values can be changed to display an image. Bitmaps can require a large amount of storage, especially when using colour. The greater the number of pixels the higher the resolution therefor the larger the file size.
Describe the purpose of the Basic computer architecture components and how they are linked together including:  
processor  
The processor is the part of the computer which execute the program, controlling the hardware and software of the computer system. It is composed of three parts.

Control Unit, Arithmetic and Logic Unit, and Registers

CU, Ah Luv U, Right.
control unit  
This is the part of the processor which controls the execution of the program. It uses a clock pulse to sync all parts of the computer, measured in Hertz (Hz). This is often used to measure the speed of a computer. You would expect a 3GHz computer to be faster than a 1GHz computer.
Arithmetic and Logic Unit (ALU)  
This part of the processor performs calculation and is used to evaluate logical decisions (AND OR NOT)
registers  
This is a temporary storage area inside the processor. It is used to store instructions, memory locations or values currently in use. Resetting a processor will clear these values.
memory  
Computer memory can either be RAM or ROM.

Random Access Memory is used to store the data currently being processed, it is volatile meaning that its contents are lost when the power is turned off.

Read Only Memory is used to store programs or data that cannot be changed, such as the operating system or serial number. Contents are not lost when power is removed.
Units of storage

  • bit
  • Byte
  • KB
  • MB
  • GB
  • TB
  • PB
  

  • bit = Binary Digit (0 or 1)
  • 1 Byte = 8 bits
  • 1 KiloByte = 1024 Bytes
  • 1 MegaByte = 1024 KB
  • 1 GigaByte = 1024 MB
  • 1 TerraByte = 1024 GB
  • 1 PetaByte = 1024 TB

 

  
Data Bus  
This is used to carry data from the processor to peripherals (other parts of the computer) and vice versa. The data bus is therefore a bi-directional bus. A bus is simply a group of wires.
Address Bus  
This is used to carry the location of the data from the processor to memory and peripherals. This is a Unidirectional bus.
Interfaces  
An Interface is a hardware device that compensates for differences between the processor and peripheral devices. For example, sound data is analogue and the interface would need to change it to digital before it could be used. There are a number of common interfaces, which are disused later.

N5 – Arrays (revision)

To read and write information to an array in Python we must first create the arrays, lines 4&5 do this for us.

The for loops on lines 8,12 & 17 are used to process each of the arrays in turn

  • The for block for line 8 and 9 gets the 10 subjects and stores them in the subjects array.
  • The for block on line 12 and 13 displays each subject name and stores the marks for that subject.
  • Finally lines 16-20 display the information from each array in one table.
# get and display 10 subjects and marks

# create two arrays to store the information
subjects=[""]*10
marks =[0]*10

#Get all the subjects
for index in range(10):
    subjects[index]=input("What is the name of subject" + str(index+1))

#Get all the marks
for index in range(10):
    marks[index]=int(input("What is the mark for " + subjects[index]))

#display subjects and marks
print("-"*25) # Pretty divider
for index in range(10):
    print(subjects[index],"\t",marks[index])

print("-"*25)

Read more

Test Post – Python Code

Using <pre />

print("Please enter your name")
name = input()
if name == "Bob":
    print("Hello " + name)
else:
    print("Sorry only bob allowed " + name)

Using Plugin :)

print("Please enter your name")
name = input()
if name == "Bob":
    print("Hello " + name)
else:
    print("Sorry only bob allowed " + name)

What line contains the conditional statement? You can see the answer below.

print("Please enter your name")
name = input()
if name == "Bob":
    print("Hello " + name)
else:
    print("Sorry only bob allowed " + name)