proper implementation of cdev_init and cdev_add for 25 nod done.
driver register and unregister with kernel perform using register_chrdev function and alloc_chrdev_region and unregister with unregister_chrdev_region . one issue faced: Instead of whole program execute successfully there is no output and after reboot it gives correct output.
assignment completed using mutex and semaphore both.
project completed using message queues but facing problem in semaphore
ptr=malloc(sizeof(char)*4); if length of available characters in string is more than 4 then memory allocation to pointer cross the limit but it does not affect the output to print the string.