The thread library function performs the following actions to context switch between user level threadsCopy all live registers to Thread control Block (TCB)Restore the state of the thread to run next i.e (copy the values of live registers from (TCB) to registers)Move to the next thread to execute

For the conventional time �shared processes, Linux uses a prioritized, credit-based algorithm. Each process possesses a certain number of scheduling credits; when a new task must be chosen to run, the process with most credits is selected. Every time that a timer interrupt occurs, the currently running process loses one credit; when its credits reaches zero, it is suspended and another process is...

A hard real-time system guarantees that critical tasks complete on time. This goal requires that all delays in the system be bounded from the retrieval of the stored data to the time that it takes the operating system to finish any request made of it.A soft real time system where a critical real-time task gets priority over other tasks and retains that priority until it completes. As in hard real...

Hard disk is the secondary storage device, which holds the data in bulk, and it holds the data on the magnetic medium of the disk.Hard disks have a hard platter that holds the magnetic medium, the magnetic medium can be easily erased and rewritten, and a typical desktop machine will have a hard disk with a capacity of between 10 and 40 gigabytes. Data is stored onto the disk in the form of files.

->Ensure that the system will never enter a deadlock state.->Allow the system to enter a deadlock state and then recover.->Ignore the problem and pretend that deadlocks never occur in the system; used by most operating systems, including   UNIX.

When a process requests an available resource, system must decide if immediate allocation leaves the system in a    safe state->System is in safe state if there exists a safe sequence of all processes.  ->Sequence <P1, P2� Pn> is safe if for each Pi, the resources that Pi can still request can be satisfied by  currently available resources + resources held by all...

Process Termination:->Abort all deadlocked processes.->Abort one process at a time until the deadlock cycle is eliminated.->In which order should we choose to abort?Priority of the process.How long process has computed, and how much longer to completion.Resources the process has used. Resources process needs to complete.How many processes will need to be terminated? Is process interactive...

Address binding of instructions and data to memory addresses can happen at three different stagesCompile time:  If memory location known a priori, absolute code can be generated; must recompile code if starting   location changes.Load time:  Must generate relocatable code if memory location is not known at compile time.Execution time:  Binding delayed until run time if the...

Dynamic Loading:->Routine is not loaded until it is called->Better memory-space utilization; unused routine is never loaded.->Useful when large amounts of code are needed to handle infrequently occurring cases.->No special support from the operating system is required implemented through program design.Dynamic Linking:->Linking postponed until execution time.->Small piece of code,...

How to satisfy a request of size n from a list of free holes?First-fit:  Allocate the first hole that is big enough.Best-fit:  Allocate the smallest hole that is big enough; must search entire list, unless ordered by size. It produces the smallest leftover hole.Worst-fit:  Allocate the largest hole; must also search entire list.  Produces the largest leftover hole. First-fit...

Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request. External Fragmentation: External Fragmentation happens when a dynamic memory allocation algorithm allocates some memory and a small piece is left over that cannot be effectively used. If too much external fragmentation occurs, the amount of usable memory is drastically...

Segments can be of different lengths, so it is harder to find a place for a segment in memory than a page. With segmented virtual memory, we get the benefits of virtual memory but we still have to do dynamic storage allocation of physical memory. In order to avoid this, it is possible to combine segmentation and paging into a two-level virtual memory system. Each segment descriptor points to page...

 A page fault occurs when an access to a page that has not been brought into main memory takes place. The operating system verifies the memory access, aborting the program if it is invalid. If it is valid, a free frame is located and I/O is requested to read the needed page into the free frame. Upon completion of I/O, the process table and page table are updated and the instruction is restarted.

 Recall that paging is implemented by breaking up an address into a page and offset number. It is most efficient to break the address into X page bits and Y offset bits, rather than perform arithmetic on the address to calculate the page number and offset. Because each bit position represents a power of 2, splitting an address between bits results in a page size that is a power of 2.

An address on a paging system is a logical page number and an offset. The physical page is found by searching a table based on the logical page number to produce a physical page number. Because the operating system controls the contents of this table, it can limit a process to accessing only those physical pages allocated to the process. There is no way for a process to refer to a page it does not...

- Write a script to convert all DOS style backslashes to UNIX style slashes in a list of filesI am not sure if this question has been asked before. I am newbie to this I would appreciate you answer?