Lesson 2b (SPIN) Flashcards
Key points of Hydra
Kernel mechanism for resource allocation. Capability based resource access. Resource manager as coarse-grain objects to reduce border crossing overhead
What was the disadvantage of MACH
It focused on portability which made it slow
In SPIN where were extensions located
They were colocated with the kernel
How was modularity enforced in SPIN
Using the compiler and a strongly typed language
What language was SPIN written
Modula-3
Which of the three OS structures is SPIN similar to?
DOS
How did SPIN avoid security issues
Using logical protection domains
What are the benefits that modula-3 provided
Safety+Encapsulation. type safety, auto storage management. Objects, threads, exception, generic interfaces
How was fine grain protection provided
via capabilites
What are capabilities essentialy
pointers
How are Modula-3 pointers safe
They are type specific. This allowed for protection the os takes advantage of
List the spin mechanisms for protection domains
Create, Resolve, combine
Create
init with object file contents and export names
resolve
names between source and target domain, Once resolved resource sharing at memory speed
combine
to create an aggregate domain
How are core services included
provided components implement specified interfaces
What makes the extensions flexible
co-location systems extensions are dynamically linked
What language in SPIN can applications be written in?
Any language
Perfomance
It performed better than MACH comparable to Micro
How does the kernel know where to send message and interupts
It has an event dispatcher and service can create handlers
How are services siloed in memory
they are not, all services share the same address space
How are system services built
As logical extensions
What is the limit of an extensions
None really. The extension can be an entire OS
How are events in the dispatcher ordered
Order of events isn’t guaranteed
