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(28 cards)
What was the monolithic kernel?
An early kernel that was simple in design. It was executed as a single stating binary file, and communication within it was simple and fast
What is a microkernel?
A smaller kernel with only essential functions built in. All execution is done with processes.
What advantage does microkernel offer over monolithic?
It’s coding process is faster, and its easier to maintain.
What kind of environments allow a microkernel to excel?
HPC and distributed environments
What is a disadvantage of the microkernel?
Overhead of communication
What is multithreading?
A process or task is divided into threads that can run concurrently
What is a permanent fault?
A hardware failure
What is a transient fault?
One that occurs only once
What is an intermittent fault?
One that occurs many times and is unpredictable
What is mean time to repair?
The mean time needed to make a repair
What is mean time to failure?
Just that
What is availability?
MTTF/(MTTF+MTTR)
What is the virtual machine approach?
Lets one or more cores be devoted to a process, and the processor is left alone to complete it
What was good about re-writing unix in C?
It proved that other OSes could be written in programming languages
What order does unix sit?
Hardware -> kernel -> system call interface -> UNIX commands and applications
What was SVR4?
An OS by ATT and Sun that aimed to combine features of prominent OSes of the day
What is BSD?
Berkeley software distribution. Basis of modern Linux/Unix. Included best separate pieces of it combined together
What kernel does Linux use?
Monolithic, but it is very modular
What is a modular monolithic kernel?
Its the same old kernel but it only loads what it needs, i.e. no CD things if there is no CD drive
What is a Frame
A fixed length block of memory
What is a page?
A fixed length block of data that resides in secondary memory and may be copies into a frame of main memory
What is a segment?
A variable length block of memory that resides in secondary memory
Relocation
Moving processes between areas of memory
Base
Address of a starting process
