Kernel Flashcards
where does the kernel reside and with what?
in protected space
alongside process manager, scheduler, IPC, exception handlers, resource managers.
how does the user space connect with the kernel
system calls
what does the kernel do
it is responsible for implementing mechanisms and there is debate over whether it should be responsible for policy too
describe the difference between mechanism and policy using scheduling
scheduling mechanism: the code the saves the context of a process and restores the context of another.
scheduling policy: responsible for when to switch, decides time slicing, priority etc
what are the two types of kernel
monolithic and microkernel
describe a monolithic kernel
everything is included in the kernel and runs in the privileged mode
what are the disadvantages of a monolithic kernel
size- code begins to bloat as it develops
reliability- a bug will crash the whole system
portability- it is system specific
what is a micro kernel
kernel contains handlers which need to be privileged but functions that do not are user mode processes.
give examples of user mode processes in a micro kernel
filing system
GUI
device drivers
what are the disadvantages of a micro kernel
speed- there is a need for more communications (system calls) that leads to a greater overhead
complexity- greater complexity gives more potential for problems.
