• it has a header that contains the destination address, the packet number, and the originator’s address
• it has a payload
• it has a trailer.

input

• from sensors
• from camera images [Max 2]

processing

• analyse data from sensors
• calculate average traffic flow/speed
• send signals to adjust change lights/timing

output

• change lights at the junction
• change timing plan

Direct changeover – new system replaces existing system immediately/overnight

 Parallel running – new system runs alongside/together with existing system

Parallel running – there is always the old system to fall back on in the event of the new system failing/information is not lost/always a second copy

Direct changeover – if things go wrong lose all data/old system is not available

Direct changeover – training is more difficult to organise

Parallel running – training can be gradual Parallel running is more expensive to implement than direct changeover....

Direct changeover is a quicker method of implementation than parallel running

Direct Changeover: The old system is stopped completely, and the new system is started. All of the data that used to be input into the old system, now goes into the new one.

 Parallel Running: The new system is started, but the old system is kept running in parallel (side-by-side) for a while. All of the data that is input into the old system, is also input into the new one. Eventually, the old system will be stopped, but only when the new system has been proven to work.

(a) Disk mirroring- Data is written on two or more disks simultaneously.

(b) Encryption - Contents are scrambled so they cannot be understood without a decryption key

(c) Backup - A copy of the data is taken and stored in another location

• connecting wireless headphone to a phone
• Using a wireless mouse, keyboard etc
•  

Cloud computing refers to the delivery of on-demand computing resources over the internet. Instead of relying on a local server or personal computer, cloud computing allows users to access and utilize a wide range of computing services and resources hosted on remote servers.

• Sarah could keep all of her files in the cloud and easily access these with her devices. This way she does not have to keep different version on her desktop and laptop.
• Flexibility she could access the files from other devices such as the library etc.
• Disaster recovery if she accidently dropped or damaged a device – all files would be easy to access.

• By setting the validation rule for the input controls on the property sheet in design view
• By use of VBA to restrict user inputs for a given control on a form
• By use of queries to restrict options available for the user in a combo box or listbox
• Setting correct data types for the fields in table the design
• Enforcing referential integrity in database relationships
• Use of input mask for the controls on the property sheeet in design view

(a) Buffer

• temporary storage or memory which compensates for the difference speed of peripherals and the CPU

(b)batch processing

• processing doesn’t start until all data is collected
• JCL (any reference to Job Control Language)
• no need for user interaction
• processed all in one go
• done at “quiet” times
• e.g. billing, payroll, cheque processing

(c) e-commerce

• electronic commerce
• buying and selling products/services using the internet/computer networks

(d) simulation

• studying the behaviour of a system by using a model/mathematical representation
• results can be predicted
• e.g. flight (or other) simulator, modelling hazardous chemical process

(e) Email

• sending messages from one device to another using computer networks/Internet

Prefixing an extra sign bit- A negative number is representes by prefixing a digit 1 to the number

Ones complement- This is flipping the binary equivalent of the number

Twos complement- this involves getting the ones complement and then adding a 1

• Object code refers to a program in machine language while source code to a program in a high level language that must be translated to object code for it to be machine readable

• This approach causes minimum disruption

• Unsigned integers store more positive values

• Standards specify a set of rules for hardware and/or software used in network communications. Because all manufacturers must adhere to the standards when manufacturing network hardware or software, it means that all devices should be able to communicate, regardless of manufacturer.

• Software may be designed to run on 1 core and not multiple cores
• depends on the task(s)  i.e some tasks cannot be split across cores
• Clock speed also affects speed i.e dual core may have a faster clock speed and quad-core may have slower clock speed so one task may be run faster/slower
• RAM size also affects speed i.e Quad-core may have less RAM  amount of VM being used
• Cache size also affects speed i.e Quad-core may have less cache

1. Hardware failure
2. Corrupted software files
3. Hacking into the system
4. Power failure

1. Low level languages do not resemble natural languages they are made up entirely of bit patterns
2. Low level languages produce code that is executed faster as it is already in a format the CPU can execute / does not need to be translated.
3. High level languages are easier to understand / learn as commands are more like English / identifiers can be meaningful .
4. High level languages are easier to use leading to fewer errors.

2.1.1 Explain the concept of open source in the context of FOSS. (2)

• Is a software whose source available and user can modify and redistribute

Give ONE example of a free operating system the company could install on a laptop. (1)

• Linux
• FreeBSD
• ReactOS
• Android
• ChromeOS
• OpenSolaris

2.1.3 State TWO disadvantages of using free open-source software.

• Lack of support
• Security risks
• Compatibility issues
• Hidden costs

• colour codes // colour in HTML/CSS
• error messages
• locations in memory
• memory dump // debugging 
• IP(v6) address
• ASCII // Unicode
• assembly language
• URL.

• Because it will be subject to movement  and it does not use mechanical/moving parts

          OR

• Solid state storage is smaller/more compact so better suited for a wearable device

          OR

• Doesn’t have moving parts  because they could be disrupted during use

• All nodes ‘listen’ for traffic to sense when the network is idle.
• When a node wishes to transmit, it transmits a ‘request to send’ frame’ (RTS)
• The intended receiving device will transmit a ‘clear to send’ (CTS) frame if it is available.
• All other nodes ‘sense’ the network is busy and wait a random amount of time before trying to transmit