PAPER 1

• ACID stands for atomicity, consistency, Isolation and Durability
• Isolation ensures that concurrent transactions do not interfere with each other.
• Consistency ensures that no transaction can violate any of the defined rules for maintaining the integrity of the database
• Atomicity requires that a transaction must be processed in its entirety or not at all
• Durability ensures that once a transaction has been committed, it will remain so, even in the event of a power cut or a network failure.
• A firewall is a security checkpoint designed to prevent unauthorised access between two networks
• Packet filtering, also referred to as static filtering, controls network access according to network administrator rules and policies by examining the source of the destination IP address in packet headers
• A proxy server intercepts all packets entering and leaving a network, hiding the true network address of the source from the recipient
• Simple mail transfer protocol is used to transfer outgoing emails from one server to another or from an email client to the server when sending an email
• The internet protocol stack is a set of protocols that pass incoming and outgoing data packets up and down the layers. These four layers are: Application layer, Transport Layer, Internet layer and Link layer
• The application layer uses protocols relating to the the application being used to transmit data over a network.
• The transport layer uses the transport control protocol to establish an end-to-end connection with the recipient. The data is then split into packets and labelled with the packet number, the total number of packets and the port number through which the packet should route.
• The purpose of the control bus is to transmit command, timing and specific status information between system components.
• The data bus is typically consisting of 8, 16, 32 or 64 separate lines, provides a bi-directional path for moving data and instructions between components
• The address bus transmits the memory address of words that are used as operands in program instructions, so that the data can be retrieved and sent back to the processor
• A bus is a set of wires that connects the components of a computer system together.
• The internet layer adds the source and destination IP adress
• The link layer adds the MAC address identifying the NIC's of the source and destination