Final answer:
A computer with 4 SATA ports can have 4 hard drives connected, one per port.
Step-by-step explanation:
If your computer has 4 SATA (Serial ATA) ports, the number of hard drives that can be directly connected to these ports is 4. Each SATA port supports one device, which means you can install a hard drive to each one, provided the physical space in your computer case and power supply capacity are adequate.