PART II OPERATING SYSTEMS LECTURE 8 SO TAXONOMY Ştefan Stăncescu 1

TAXONOMY OS The operating system on a real H/W machine are a compact package of system programs which manages the H/W i.e.: CPU, MEM, I/O, EXT MEM use local H/W system for running local programs communicates, stores, processes (in cloud, for distributed applications) providing an unified management environment on different machines 2

SO TAXONOMY The operating system creates a local VM efficient standardized friendly (or known interface easy to learn) adaptable to different tasks VM hide the real machine with complicate structure complicate handling 3

SO TAXONOMY OS classification afterresource allocation to processes - all resources fully allocated only to a process (batch - batch processing) - distributed resource allocation multiple processes (PC) OS classification after response time to the run - real time RTOS - with guaranteed response time to each process (processes are important) - without time constraints - optimal loading of computing resources (resources are important) 4

SO TAXONOMY OS classification after process management single process (dedicated system - embedded) embedded application is a process hosted by the unique OS process dedicated to it cooperative management of processes running process cooperates in management preemptive management OS contains a supervisor which regulate run or abort process run 5

SO TAXONOMY OS classification after executable SO structure - Compact SO with a single executable file all resources simultaneously available -Hierarchical (multilayered) SO with a module architecture - levels of services provided by resources => to the user each level is an abstract stage adaptation H/W resource system software levels the user 1.The operator (user) and user processes 2.Operator-process communication and I/O management 3.Memory and disc (files) management 4.UC process allocation and multiprogramming 6

SO TAXONOMY OS classification after OS executable structure (cont) kernel centered SO kernel provides reliable communication between server services and user calls I/O separated by drivers OS versions not necessarily involve kernel stability, safety, versatility client-server –with host kernel (supervisor) and server resource oriented and client modules (protected) client call server services by message passing RPC (distributed systems) 7

SO TAXONOMY OS classification after OS executable structure (cont) virtual machines VM the kernel covers (hide) the real (diverse H/W) machine each real machine converted in std. VM with special nest VM kernels over same real machine you can install multiple virtual machines (VM) each with its own resource management system (OS) installed on the same core (HAL) OS with each process with separate VM runs in separate VM environment nest VM kernel makes interprocess communication 8