MIT 6.828: JOS Lab

Lab 5: File System, Spawn and Shell

Questions

Answer the following questions:

1. Do you have to do anything else to ensure that this I/O privilege setting is saved and restored properly when you subsequently switch from one environment to another? Why?

1. Nothing else needs to be done. When switching from the file system environment to another environment, the two trap frames are completely separate. If the file system environment forks, then the child would inherit the ELFLAGS register value and hence the I/O privilege.