Final answer:
Mini power connectors were commonly used for PATA (Parallel ATA) drives in older computer systems, before being overtaken by SATA and other modern interfaces.
Step-by-step explanation:
Mini power connectors are most often used on older systems for PATA drives. PATA, or Parallel ATA, is an older standard for connecting hard drives and optical drives in computers. These connectors were typically used before the adoption of SATA (Serial ATA), which is the more modern interface used for hard drives, solid-state drives (SSDs), and optical drives. The mini power connectors supplied electricity to the PATA drives allowing them to operate within the computer system. As technology progressed, PATA has been largely replaced by SATA and other interfaces such as M.2 and NVMe, which provide faster data transfer rates and more compact connectors in the case of M.2 drives.