semaphores

Semaphores are tools used in computer systems to control access to shared resources, ensuring that multiple processes don't interfere with each other. Think of a semaphore as a signaling device with a count: when the count is positive, a process can access the resource and the count decreases; when zero, access is blocked until another process releases the resource, increasing the count. This helps prevent conflicts, data corruption, or system crashes by coordinating how processes share limited resources efficiently and safely.