Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
How could we implement locks? No matter how we choose to implement them, we must have some hardware support. One possibility for implementing locks on a uniprocessor machine is is to disable interrupts when testing/setting locks. With interrupts disabled on a single processor machine, the processor cannot switch processes, and so we can guarantee that only the active process will have access to the shared data. Another option would be to make use of atomic operations, such as test and set. This type of operation (which usually corresponds to a single atomic assembly instruction) behaves as if it used the following C function, atomically:
int test_and_set(int x) // let x be strictly either 0 or 1.{if (x) { return 1; } else { x=1; return 0; }}
All this needs to be implemented atomically, in hardware. Using this type of atomic operation, one could implement thread lock(l) simply as while test_and_set(l) {
; // do nothing} // spinlock version of thread_lock()and thread unlock(l) simply asl = 0; // we need this to be an atomic clear (or assign) instruction
The assembly instruction test and set can bemade to be atomic acrossmultiple processors. An equivalent option would be an atomic compare and swap assembly instruction. These low-level hardware solutions are then built up into high-level functions, either built into the languages, or in libraries. In general, do not implement your own locking functions, but rather use functions from a tested library. Getting things right can be tricky, and your own solution is also likely to be non-portable.
Explain the various file types A common technique for executing file types is to contain the type as part of the file name. The name is split into two parts - a name and an ext
what is deadlock
How do we keep track of where the free pieces of memory are? One idea is to maintain a set of linked-lists of free space; each linked-list will store free chunks of some given size
Multi-level page tables are tree-like structures to hold page tables. As an example, consider a two- level page table, again on a 32-bit architecture with 212 = 4 kbyte pages. Now,
Logical File System Responsible for providing the before discussed interface to the user including: File access. Directory operations. Security and protection.
advantages and disadvantages of monolithic and layered approach
Q. a number of systems automatically delete all user files when a user logs off or a job terminates unless the user explicitly requests that they be kept other systems keep all fil
Define what is Dispatcher In the Worker Model, it is the task of the Dispatcher to spawn a thread for every client-to-server connection. The Dispatcher acts as the go-between o
Q. Palm OS provides no signifies of concurrent processing. Discuss three major complications that concurrent processing adds to an operating system. Answer: a. A meth
What is the main difficulty that a programmer must overcome in writing an operating system for a real-time environment? The main difficulty is keeping the operating system with
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd