A
Describe the impact of increasing the image resolution on the quality of a bitmap graphic.
more pixels can be stored / are available
the image is sharper / less pixelated
A program is distributed by downloading the source code and its library files from a web server. Explain two reasons for compressing the files
To reduce the time it takes to download the program files from the web server // to upload them to the server in the first place
To reduce the amount of storage space used on the web server // user’s device
Data verification is one method of protecting the integrity of data. Describe one other method of protecting the integrity of data.
Validation // a validation method named or described …protects the data by ensuring that the data is reasonable / sensible and within specified bounds
State one difference and one similarity between pharming and phishing.
Difference: • Pharming is malicious code that redirects to a fake website. Phishing uses an email to prompt user action. • Pharming is automatic. Phishing requires user action.
Similarity: • Both try to obtain financial or personal information • Both are a false representation of an official organisation, e.g. a bank • Both make use of fake websites
Convert the denary number 241 to hexadecimal.
F1
Calculate the file size of a bitmap image using the following information:
image resolution of 2048 pixels wide and 1024 pixels high
bit depth of 16 bits.
Give your answer in kibibytes. .
4096 kibibytes
Describe the following features of a typical IDE:
Context‑sensitive prompts
Single stepping
Context-sensitive prompts: As the code is being written the options to complete the statement are shown
Single stepping: allows the programmer to execute the program one line at a time so that the effects of each statement can be seen
State two benefits to a programmer of distributing a program using a shareware licence.
Users are able to trial the program and may offer the programmer constructive feedback
More people might try the program because the trial is free of charge
Allows bugs to be found and corrected on a wide range of computer system configurations improving the programmer’s original program
Users that find the trial useful will buy the program so programmer gets income
Allows the program to be copyrighted and so protects the programmer’s intellectual property rights // no illegal modification allowed
he devices in an office have static private IP addresses. State what is meant by a static private IP address.
Static means the IP for that device does not change and Private means it can only be accessed/seen/used within the LAN
Give two differences between real-time and on-demand bit streaming.
Real-time is direct from source whereas on-demand is prerecorded/downloaded to view later
Real-time cannot be re-watched, on-demand can be paused, re-watched etc.
A company sells online Computer Science courses to students in different countries. The courses are stored on a public cloud.
Explain why the company uses a public cloud to store these courses.
Courses must be available to anyone who wishes to follow them
Courses must be available on the internet
Company is willing to share infrastructure with other companies (public) which is more economic for the company
State how the following security measures can be used to protect computer systems.
Firewall
Encryption
Passwords
Firewall: Monitors incoming and outgoing traffic and rejects any traffic that does not meet the set rules
Encryption: Ensures that if data is intercepted / obtained it cannot be understood without the decryption key
Passwords: Ensures only users with the correct password can access the resources // prevents unauthorised access
Explain why it is important for a programmer to join a professional ethical body.
The programmer has ethical guidelines to follow so purchasers of programs know the standards being applied, so programmer does not have to decide what is ethical or not
Clients know programmer is reputable, recognition of programmer’s skills/knowledge
There may be an entry requirement / exam so clients know that the programmer is competent
Professional ethical body provides help and support
Such as legal advice // by appropriate example
Enables programmer to attend the ethical body’s training courses to keep skills up to date // to develop skills
Describe what is meant by the following DBMS features:
Data dictionary
Logical schema
Data dictionary:
Data about the data in the database // metadata
Identifies the characteristics of the data that will be stored
Appropriate example e.g. field names, table name, validation rules, data types, primary / foreign keys, relationships etc.
Logical schema:
Conceptual design
Platform/database independent overview of the database
Is used to design the physical structure
Appropriate example e.g. Design of entities / E-R diagram / views
1 0 0 1 1 1 1 0 + 0 1 1 0 0 0 0 1 + 0 0 0 1 1 0 0 1
1 0 0 0 1 1 0 0 0 0
Describe two disadvantages of storing data on a public cloud compared to storing data on a server in a Local Area Network (LAN).
There could be a possible loss of control unlike the LAN because the data is stored on a remote infrastructure / someone else’s infrastructure.. reliance on external agency to complete tasks, e.g. backups, security
Requires reliable internet connection to ensure access to the remote data, more likely with LAN
Increased recurring costs as cloud provider charges must be paid, costs for LAN once only
Identify and describe two methods of data verification that can be used during data transfer.
Parity byte
Parity block
Checksum
One difference between an IPv4 and IPv6 address is that the numbers in an IPv4 address are separated by full stops and in an IPv6 address they are separated by colons.
Identify two other differences between an IPv4 and IPv6
IPv4 has 4 groups of digits whilst IPv6 has 8 groups
IPv4 is usually represented in denary whilst IPv6 is usually represented in hexadecimal
IPv4 groups are between 0 and 255 whilst IPv6 is between 0 and FFFF
IPv4 is 32 bits whilst IPv6 is 128 bits
Give four advantages of a wireless network compared to a wired network.
Devices can be more mobile as no physical connection is required
No cabling is needed so easier to set up
Easier to add additional devices
Multiple different device types can be connected
Describe two reasons a server that stores videos uses magnetic hard disks instead of solid state (flash) memory.
Lower cost per unit of storage so the high capacity of storage required for large number of video files will be less costly
A large number of read/write operations are being performed continuously and magnetic storage is likely to have a longer life span compared with solid state
The program files are stored on a new hard disk after they have been downloaded.
Describe the reasons why a hard disk formatter is needed for the new har
Disk needs to be prepared for initial use
Disk needs to be checked for errors
A new file system needs to be generated on the disk
The file allocation table needs to be set up
A robot includes a touchscreen for the customer to make their payment. Describe the principal operation of a touchscreen.
Resistive: The space between the conductive layers is removed/the layers touch and a circuit is completed
Capacitive: The electrical charge changes where the user pressed
The point of contact is identified ... from the change in electrical field
The software/microprocessor calculates the coordinates
Assembly language instructions are grouped. Complete each statement by writing the name of the appropriate instruction group.
Loading data into the accumulator is an example of an instruction in the ............................................................... group. Incrementing the index register is an example of an instruction in the ............................................................... group. Branching to another address is an example of an instruction in the ............................................................... group
Data movement
Arithmetic operations
Conditional and unconditional (jump) instructions
BONUS
Write the stages of the F-E cycle using register transfer notation.
MAR <- [PC]
PC <- [PC] + 1
MDR <- [[MAR]]
CIR <- [MDR]