Official OCR Computer Science A451/01 Exam ThreadWatch
Question 1: Sat nav I/O
What is a computer system?
-A system containing electronic devices that have software and hardware working together
-It is an electronic data processing machine that can take inputs and output results
Why does a computer system need input devices?
-To have data to process
Give an example of an input device for the sat nav for a disabled person and explain how it is useful.
-Keyboard. Only sensible one so far.
Why does the satnav need a secondary storage device?
-store maps, previous locations etc.
Why solid state storage?
-withstand movement, no moving parts
Why are the commands stored as binary?
-1 and 0 can easily be represented via on and off siganls. It allows easy simple logic gates. It allows less error as there are only two values
Name a task carried out by the CPU:
-To fetch/execute commands from memory
-To decode commands
-To carry out the fetch, decode, execute cycle
-Perform Logic operations
Question 2: HTML and internet
What else might be in an HTML file other than text for the webpage?
-cascading style sheets, CSS
One reason why is it good for HTML to be a standard?
-All webpages are the same (pretty much) so browsers only have to support html
-People can have gaurenteed support for their webpage
- 58 = 3A, 156 = 9C
Another question ??
Why did she compress the images before uploading?
Quicker upload, smaller webpage etc.
How does the DNS connect the user to a webpage from the URL?
The DNS has access to a database and associates the URL with a specific IP address. This can access the files and connect the user to the IP which also allows the DNS to contact the correct website.
3: Algorithm (I think)
Fill in the gaps
-'count' and 'Total / Quantity)
What is a constant and give an example?
-A value stored in a specific memory location represented by a name. The value cannot be changed while the program is running
What data type is the Mean?
Real as it could be a decimal.
What other two types of iteration are there other than For?
-repeat/do until ?
It gives an example of a validation algorithm, Give an example of a boundary value and an invalid value.
-100 or 0 are boundaries
-anything not between 0 and 100 inclusive are invalid values
Why is a database a persistent organised store of data?
-It is a structured object that contains data. It is stored in tables. (Not sure about this one)
What is a suitable data type for the ID?
Text, as it has leading zeros
How many records are there
Which field is the primary key?
-The first field, it is unique and follows the same format. It is a short number.
Name a validation method for TeacherID and Date, they must be different.
-TeacherID, follow format Letter,Letter,ID, or must be length three etc
-Date, follow format DD/MM/YYYY or it must be less than or equal to the current date
Name two features of a DBMS that allow you to make customizable applications.
-Query, ask for records with certain attributes easily, e.g this lets the admin create a query for all outstanding repairs
-Form, create a GUI to make it easier to make a query, e.g. admin enters teachers ID into search box to get their repairs.
Question 5: Cars
Describe the ethical and legal issues surrounding the development of automatic technology such as driverless cars.
-Cars follow the law always and may not cope in an emergency situation and therefore ccause harm.
-Cars and automatic devices collect data perhaps unethically or illegally
-Automation increases unemployment, not right for robots to 'take over'
-Security required and so could break the data protection Act
-Hackability, could break the computers misuse act
Question 6: OCR accounts
Two advantages of a network in the office over standalone PCs:
-Share expensive peripherals. All users can use the peripherals plugged in to any PC. This saves money as only one peripheral is needed and all the computers have access saving time.
-Share data/resources/programs. This allows quicker sharing of data and ideas over methods such as email. It is cheaper as users do not have to use physical storage devices to transfer data. Saves time as users do not have to take so long copying files as they are in a shared folder.
Name a piece of hardware to get an internet connection. Usually OCR accepts:
Router, modem (modulator-demodulator) or ADSL adapter
Name two other pieces of hardware for a network and explain:
-Router/modem/ADSL, internet connection
-Hub, connect the devices for sharing
-NIC, allows connection via Ethernet or wireless
-Server, dedicated machine to supply data to clients etc.
-switches, like a hub but faster
-Acceptable Use: User priviliges, malware protection etc
the criteria were
Have a previously stored number to guess
allow ten guesses
say to guess higher or lower
ask the user to guess
say congratulations and end the game if they guess it
I guess that it is one mark per criteria
Const Value = random number
count = 0
Ouput 'Guess the number'
Output 'enter a number'
Guess = Input
If Guess = Value Then
If Guess > Value THEN
Output 'guess higher'
if guess < Value then
Output 'Guess lower'
count = count + 1
Repeat until count = 10
output 'Sorry you did not guess the number. It was' + value
Thanks for all the input people have given
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