when does a process enters a blocked state
Process state A process transitions to a blocked state when it cannot carry on without an external change in state or event occurring. For example, a process may block on a call to an I/O device such as a printer, if the printer is not available. Processes also commonly block when they require user input, or require access to a critical section which must be executed atomically. Such critical sections are protected using a synchronization object such as a semaphore or mutex.
Lock-up period A lock-up period, also known as a lock in, lock out, or locked up period, is a predetermined amount of time following an initial public offering where large shareholders, such as company executives and investors representing considerable ownership, are restricted from selling their shares. Generally, a lock-up period is a condition of exercising an employee stock option. Depending on the company, the IPO lock-up period typically lasts between 90â€“180 days before these shareholders are allowed the right, but not the obligation, to exercise the option.