Explain why using more than one thread can help performance and how it can hinder? what type of work for the thread makes it useful? Cover both single processor and multiprocessor
(I read in one place that when one thread is blocked by I/O no other thread under same process can run as they are User level threads..so i am getting confused by the sayings that multiple threads improve processor performance.please somebody help me...or give a link which describes all this well)\
2. whats difference between threads in Windows,Unix & Solaris(Scheduling,mapping to process,performance)?
my understanding is in windows scheduleing is based on timeslicing.in solaris preemptive tasking. also both these support multiple processoes with each having multiple threads.Where as in linux each thread is associated with a PID. so context switching takes more time and so performance less,....please correct me if i am wrong.is there something i can add to it?