Telegraphy the sense of a system that can transmit arbitrary messages over arbitrary distances. Lines of signalling relay stations can send messages to any required distance, but all these systems are limited to one extent or another in the range of messages that they can send. A system like flag semaphore, with an alphabetic code, can certainly send any given message, but the system is designed for short-range communication between two persons. An engine order telegraph, used to send instructions from the bridge of a ship to the engine room, fails to meet both criteria; it has a limited distance and
FLAGS register the FLAGS register. The conditional jump instructions use certain flags to compute. For example, codice_3 uses the zero flag, codice_4 uses the carry flag and codice_5 uses the overflow flag. Other conditional instructions look at combinations of several flags. Testing if certain bits in the FLAGS register are changeable allows determining what kind of processor is installed. For example, the alignment flag can only be changed on the 486 and above, so if it can be changed then the CPU is a 486 or higher. These methods of processor detection were not made obsolete by the CPUID instruction introduced with