Types of operating systems

Types of operating systems:


a- Real-time- a multitasking operating system that executes real-time applications through specialised scheduling algorithms to determine their performance, aiming at quick and predictable response to events. They incorporate traits of both time sharing and event-driven properties. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.

b- Multi-user - allows multiple users to access a computer system at the same time e.g.: time-sharing systems and Internet servers. Single-user operating systems can only have one user at a time although they can still be multitask systems,meaning multiple programs running concurrently.

c- Multi-tasking vs. single-tasking
The former allows more than one program to be running at the same time, while the latter has only one running program. There are 2 types of multi-tasking system: pre-emptive (the operating system slices the CPU time and dedicates one slot to each of the programs) and cooperative (each process gives time to the other processes). 

d- Distributed - a group of independent computers behave like one single entity, similar to a network cluster. The processing is distributed across the participating machines.


e- Embedded - for use in embedded computer systems (small machines like PDAs). As they run on limited resources, their design is usually efficient considering the reduced autonomy with which they operate.

Ethnography

Ethnography is the study of people and cultures, analysing the latter from the former's viewpoint, documenting the cultural development of a group.

Originally an area of anthropologist interests, it has also become popular in the social sciences, communication studies and history. Ethnography is relevant for the understanding of ethnic differences, compositions and materialism/spirituality among the observed populations. A holistic study, it usually includes history and terrain and climate features. Its purpose is to provide a basic understanding of the varied styles in human social life.

The field of anthropology originated from Europe in late 19th century, arriving in the United States at the beginning of the 20th century. The founders of ethnography are considered to be EB Tylor (1832-1917) from Britain and Lewis H Morgan (1818-1881), from the us. Franz Boas (1858-1942), Bronislaw Malinowski (1858—1942), Ruth Benedict and Margaret Mead (1901-1978), were researchers who contributed the idea of cultural relativism to the literature, focusing on the use of documents and informants, including experiencing life as one of them.