Correct Answer: Commonly, the different attributes for a file structure are naming,size, identifier, a level of protection, supported file types and location for the files
3. What resources are used when a thread is created? How do they differ from those when a process is created?
Correct Answer: When a thread is created the threads does not require any new resources to execute the thread shares the resources like memory of the process to which they belong to The benefit of code sharing is that it allows an application to have several different threads of activity all within the same address space Whereas if a new process creation is very heavyweight because it always requires new address space to be created and even if they share the memory then the inter process communication is expensive when compared to the communication between the threads
4. What are the stipulations of C2 level security?
Correct Answer: Time taken for switching from one process to other is pure over head Because the system does no useful work while switching So one of the solutions is to go for threading when ever possible
6. What are the typical elements of a process image?
Correct Answer: User data: Modifiable part of user space May include program data, user stack area, and programs that may be modified User program: The instructions to be executed System Stack: Each process has one or more LIFO stacks associated with it Used to store parameters and calling addresses for procedure and system calls Process control Block (PCB): Info needed by the OS to control processes
7. Define latency, transfer and seek time with respect to disk I/O.
Correct Answer: Seek time is the time required to move the disk arm to the required track Rotational delay or latency is the time it takes for the beginning of the required sector to reach the head Sum of seek time (if any) and latency is the access time Time taken to actually transfer a span of data is transfer time
Correct Answer: A binary semaphore is one, which takes only 0 and 1 as values They are used to implement mutual exclusion and synchronize concurrent processes
Correct Answer: Load Sharing: Processes are not assigned to a particular processor A global queue of threads is maintained Each processor, when idle, selects a thread from this queue Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis Gang Scheduling: A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis Closely related threads / processes may be scheduled this way to reduce synchronization blocking, and minimize process switching Group scheduling predated this strategy Dedicated processor assignment: Provides implicit scheduling defined by assignment of threads to processors For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program Processors are chosen from the available pool Dynamic scheduling: The number of thread in a program can be altered during the course of execution