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CS topic 7 and operating systems (Operating system - The low level…
CS topic 7 and operating systems
Operating system - The low level software that runs the PC
Device manager
Memory manager
Process manager
Makes sure that every process gets a fair share of the CPU's time
Enables the CPU to multi-task, using interupts
multi-tasking: The CPU seems like it's doing many processes at once, when in reality it switches between processes really quickly
interrupt: An interrupt is a signal coming from a piece of hardware or software
Keeps track of what every program is doing right now (running, ready, or blocked) via polling.
polling:
Easy to implement (no special hardware required)
Give the CPU more control over what it does
Wastes CPU time
blocking: Blocking is when a program stops itself from being executed until certain resources that it needs are available.
File manager
Allocates files when they are needed and de-allocates them when they're not. (Puts them into and out of RAM)
Allows or restricts certain users from accessing files
If users are allowed to access a file, it looks what they're able to do with the file (Read, write, read-write?)
Controls the hardware and software and enables other software to run consistently