There are three types of genetic disorders: 1  Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example. 2  Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. 3  Complex disorders, where there are mutations in two or more genes.
OSI model. The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols.
The OSI model defines standards for: 1  The way in which devices communicate between each other. 2  The means used to inform devices when to send data and when not to transmit data. 3  The methods which ensure that devices have a correct data flow rate. 4  The means used to ensure that data is passed to, and received by the intended recipient.