chapter 2 Flashcards
whats a process?
a process is a program in execution
Process Control Block (PCB)
is a data structure that stores all the info about a process, it is used by the CPU to manage the execution of the process
Process States
RUNNING, BLOCKED and READY
CPU Scheduling (CPU Zuteilung oder Ablaufplannung)
refers to the method used by the CPU to decide which process in the system should be allocated CPU time at any given moment. Primary goal is to ensure the ordered flow of competing processes
Preemption - Verdrängung
temporarily halt a currently running process, types of events that lead to preemption are: interrupts, higher-priority processes becoming ready, or time-slicing in round robin scheduling
Inter-Process Communication (IPC)
enables multiple processes to cooperate, work together, share data and synchronise their actions to achieve common goals.
Types of IPC: local and remote
local IPC: communication between processes running on the same machine, they can communicate through the shared mem
remote IPC: communication between processes running on the different machines, they can communicate over a network (clients and servers)
Address mapping
is the process of translating logical @ (used by programs) into physical ones (used by hardware).
Placement strategies of addresses in mem
OS must decide the location of mem to be allocated:
- compaction: moves around processes to create a large block of free mem
- fragmentation: mem is broken into small, not attached blocks
Replacement strategies
when mem is full, OS needs to swap out some area to the secondary storage to free up some space, these strategies decide which mem area is to be swapped out
Non-Uniform Mem Architecture (NUMA)
mem design used in multiprocessor systems, where each CPU has its own local mem but can also access memory attached to other CPUs. The CPUs communicate viw HyperTransport
