Shortest Seek Time First (SSTF) is a disk scheduling algorithm that selects the disk I/O request that is closest to the current head position of the disk. By minimizing the distance the read/write head must move, SSTF aims to reduce the overall time taken to service requests. This approach can improve efficiency, especially in systems with many requests. However, SSTF can lead to a problem known as "starvation," where some requests may wait indefinitely if they are consistently farther away from the current head position. This can occur in high-demand situations, making it essential to balance efficiency with fairness in disk scheduling.