What type of storage did ENIAC primarily use?

ENIAC, the Electronic Numerical Integrator and Computer, primarily used punch cards for inputting and storing its data. Punch cards were a common method of data storage during the time ENIAC was developed in the 1940s. These cards allowed data and instructions to be physically represented through holes punched in the cards. The use of punch cards was an efficient means for programmers to input the information into the machine, as they were widely used in computing long before magnetic tapes or hard drives became available.

In contrast, magnetic tapes, hard drives, and floppy disks were developed later as technology advanced. Each of these later storage methods provided improvements in data storage capacities and retrieval speeds, but they were not part of the ENIAC's architecture or operational design. Understanding the historical context of ENIAC's components highlights the significance of punch cards as an early data storage method in computing.