Terminals supplanted by smart PCs Many systems now servers , responding to requests generated by clients Compute-server system provides an interface to which a client may send a request to perform an action (e.g. run a database) File-server system provides interface for clients to store and retrieve files
Peer-to-Peer Computing Another model of distributed systems P2P does not distinguish clients and servers All nodes are considered as peers Each may act as client, server or both Node must join P2P network Registers its service with central lookup service on network, or Broadcast request for service and respond to requests for service via discovery protocol Examples include Napster and Gnutella , that allow users to exchange files. Voice over IP ( VoIP ) used by Skype allows clients to make voice calls and video calls and to send text messages over the Internet.
Real-Time Embedded Systems Embedded systems run real-time operating systems. Generally there is no user interface. They perform managing and monitoring of the hardware. Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems (car engines, manufacturing robots, DVDs, microwave ovens, firewalls,etc.) Real-time OS has well-defined fixed time constraints Processing must be done within the defined constraint. Data brought by sensors to the computer, must be analyzed and corresponding control adjustments must be done in a small time interval Correct operation only if constraints met
Cloud computing Systems Cloud computing is a type of computing that delivers computing, storage, and even applications as a service across a network. Public clouds are available via the Internet to anyone willing to pay for the services
Personal Computer Systems Personal computers – computer system dedicated to a single user. I/O devices – keyboards, mice, display screens, small printers. Can adopt technology developed for larger operating system. May run several different types of operating systems (Windows, MacOS, UNIX, Linux) Client PCs, printers, servers
Mobile Systems Personal Digital Assistants (PDAs) Handheld smartphones, tablets, etc Use IEEE 802.11 wireless, or cellular data networks for connectivity Leaders are Apple iOS and Google Android Issues: Limited memory Slow processors Small display screens.
History of Operating Systems First Generation: *1945-1955 *Vacuum Tubes *OS: Plugboards Second Generation: *1955-1965 *Transistors *OS: Batch Systems Third Generation: *1965-1980 *Integrated circuits *OS: Multiprogramming Fourth Generation: *1980-present *Large scale integration *Personal computers *OS: personal systems Next Generation : *???? *System connected to high speed networks *Wide area resource control *OS: net-centric computing, embedded systems.
- Fall '19
- Distributed systems, Parts of the OS