What should a technician check to determine if an additional hard drive can be added to an older computer?

A technician should check for an available PATA/SATA connection when determining if an additional hard drive can be added to an older computer because this connection is necessary for interfacing the hard drive with the motherboard. PATA (Parallel ATA) and SATA (Serial ATA) are types of interfaces used for connecting storage devices, such as hard drives, to a computer.

If a PATA/SATA connection is available, this indicates that there is a way for the new hard drive to communicate with the system. Additionally, considering the older nature of the computer, limitations on the number of connections may exist, making it critical to verify that appropriate interfaces are free for use with the additional hard drive. Checking the availability of installation space and power supply is also important, but those aspects are secondary to confirming the presence of the necessary data connection.

Looking at the other options, an available USB port is typically used for peripherals and external storage rather than internal hard drives. An available PCI slot is intended for expansion cards, not for storage devices. Available RAM slots pertain to memory upgrades rather than hard drive installations, hence they are not relevant to adding a hard drive. Therefore, the PATA/SATA connection serves as the crucial factor for adding an internal storage device.