Edexcel GCSE Computing June 2015 exam paper can be downloaded here



Edexcel GCSE Computing June 2015 mark scheme can be downloaded here
1A Answer


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Edexcel computer science Steve Cushing - p.193-194
1B answer
Data Data
Instructions

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1C answer
121

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2a answer
122

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2b answer
IF (statement)

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Edexcel computer science Steve Cushing -
3a answer
0000 1100

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Edexcel computer science Steve Cushing -
3a answer
1111 0010

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Edexcel computer science Steve Cushing -
3B answer
1000 0001

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4A answer
The result of the calculation cannot fit into the size of the location assigned to hold it
Two 8-bit numbers added together resulted in a number that could not be stored in 8 bits
The addition resulted in a number >= 1 0000 0000 binary (note the overflow out of the destination field)
The result is > 255
The result needs 9 bits to store it

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4B answer
Introduces errors in subsequent calculations
Compounds errors in subsequent calculations; snowballs
Signed numbers may change sign
Any indication that arithmetic performed on inaccurate calculated numbers results in subsequent inaccurate results
Introduces errors in subsequent calculations
Compounds errors in subsequent calculations; snowballs
Signed numbers may change sign
Any indication that arithmetic performed on inaccurate calculated numbers results in subsequent inaccurate results

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5a answer


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5b answer


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5c answer
Q=(R OR B) AND S

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Edexcel computer science Steve Cushing -
2a answer
Identifying any two (2) of the following (Maximum 2 marks):
Database
Bibliographic
Project Management
Presentation
Desktop Publishing
Word Processing
Web Browser
Image Editing
Video Editing
Email
Animation
CAD (not expected)
Programming Environment
Live Chat –Only if example confirms working context
Exclude software whose main purpose is entertainment
Any other appropriate software which could sensibly be used in a general working environment
 
Any two (2) examples of software use (Maximum 2 marks):
Answers may include
Image Editing –Cropping images for insertion into a presentation
Live Chat –For getting technical support help from a vendor support site
Web Browser –For looking up the addressof a colleague at a different university
Presentation –Showing results of his research to colleagues at a conference.
Bibliographic –Keeping track of sources for his research.
Video Editing –Creating a video to put on YouTube of his lectures for his students.
CAD -molecular, synthetic, and genetic biology
Programming environment  –Creating customised models
 


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6a answer
Any 4 from:
Software can be redistributed
Source code is available
Source code can be modified
Modified code can be redistributed
A fee can be charged for the software
A fee is not usually charged forthe software
Modified code must be made available under the same licence as original code. 
Licence may require an acknowledgement of the original author to be included in the code.
Source code can be freely used, changed and shared by anyone

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6b answer


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7 answer
One mark for name and one mark for use (must match)
Control Unit (CU)
o Sends signals to other components to coordinate the cycle
Arithmetic / Logic Unit (ALU)
o Performs arithmetic (+,-,/,*, etc.) and logic (AND,NOT, OR, etc.)
Registers
o Very fast storage locations which hold instructions, data, or memory addresses.
Cache (Not expected)
o Sits between components in the microprocessor to make up for the difference in physical speed of the components
Address Bus
o Holds the address of physical memory or the address of an input/output device that is to be read from/written to
Data Bus
o If an instruction needs data, the data is loaded onto the data bus before being read by the CPU
o All data/instructions moved here to go to or from Memory
Clock
o Provides the timing for the cycle
 
Other correct uses should be awarded.

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Edexcel computer science Steve Cushing -
8 answer
Accept anythreefrom the following. 1 mark each to a max of 3 marks:
The computer appears to be runningmore than one program/process at a time. 
More than one process can be loadedinto memory at one time.
Each process has its own memory space/partition.
Each process is given a small amount of time(time slice) to execute in the central processing unit.
Processes are held in a queue/FIFO list.
O/S switches between processes
Some processes may have higher prioritythan others may.
Higher priority processes may be given more timeslices/processing time.
Processes can communicate by using shared memory
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9ai answer
Any two of:
Implement formulas which represent the relationships between the given data variables, such as hours of sun and quantity of honey.
Use a programming language to write a customised application to model the colony
Allow user to input initial values for data variables (food, sun)
Use graphical user interface components (boxes, sliders) to adjust input variables will show effects on outputs
Present outputs using graphs showing relationships between food and sun, etc.
Present outputs showing real number of bees and resources (yellow dots are bees; red dots are pollen)
Variables could be changed in real-time with immediate update to the screen(e.g. move a slider, the amount of pollen decreases)
 
Any other appropriate and correct response incorporating modelling, simulation, or visualisation shouldbe awarded.

 
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9aii answer
Pixel
Resolution
Colour depth


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9B answer
Magenetic
Optical
Solid state

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10a answer
Award  1 mark for each correctanswer to a maxof 2marks
Any two of the following:
o Timestamp
o Sequence number
o Version
o Protocol type
o Data
o Flags
o Size
o Routing information
o Any other appropriate answer
 
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10b answer
Identifying errors(introduced during transmission)


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10c answer - (first half)
Divide 4096 by 1024


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10c answer - (second half)
 
Internet (Any 1 of the following):
Interconnected networks of networks/machines/hardware
Geographically distributed networks/machines/hardware
Uses protocols for communication
 
World Wide Web (Any 1 of the following)
The information stored on the hardware
Pages of information stored on servers(pages written in HTML)
Uses HTTP/ HTTPSto send/receive pages between servers and clients
 
Accept any other correct comparison



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11a answer
 Line 5-10

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11B answer
 Any one of the following:
o The <li></li> tags refer back to line number 10/the “li” style
o The <a></a> tags refer back to line number 6/the “a” style
o The tags <li> and <a> refer back to the information in the CSS
 


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11c answer - (First half)
Amplitude

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11c answer (second half)
Any one of the following –1 mark
(The more samples,)the smoother the digital representation of the original audio. 
(Higher sampling rates)result in less distortion of the original audio
This makes the resulting digital representation more accurately match the original audio. 


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12 answer
Must have idea of runs(1) being compressed to a single item + a count of that item (1)
Example:
Simple mono-chrome icon will have long sequences of bits of same colour(1)
Sequences/runs of identical data are translated/stored as a single data value and a count(1)


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Edexcel computer science Steve Cushing -
12 answer
Any three of the following impacts:
Pollution (water, air, noise) resulting from the manufacturing process
High energy and water volumes needed for the manufacturing process
Mineral mining contaminates ground water
Mineral (copper, gold, silver, lithium) resource depletion
High energy use to keep machines cool with air conditioning or fans
Contain toxic components which means computing devices are hazardous waste
Batteries (laptop, lithium cells) disposal is hazardous and needs specialised disposal facilities
Computing devices sent to landfills contaminate ground and water resources
Any other appropriate responses as long as they’re distinct from each other
 
Any one of the following actions:
Check national and local legislation
Some countries/states/regions require sellers to recycle own waste
Research recycling facilities to see if e-waste is acceptable
Find if local/national/regional government agencies charge for collection and disposal of e-waste
Find sellers offering exchange old for new + cost purchase options
Find charities (local, regional) which take donations of old devices
Turn off machines when not in use to save energy.
Any other appropriate response as long as it is interpretable to match an impact.


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Edexcel computer science Steve Cushing -
12 answer
Any two of the following
Easier / faster to:
o Sort
o Search (by using queries)
o Produce reports
o Analyse data
o Keep organised
 

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Edexcel computer science Steve Cushing -
12 answer
Primary Key

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12 answer
Foreign key

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12 answer
 
Any one of the following:
o To form a relationship between the tables
o To make connections between the tables
o To facilitate the use of queries across tables
o To relate the records in one table to records in another
 


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