As bit patterns.
A punched card.
In both main and secondary memory, information is stored as patterns of bits. Recall from chapter two what a bit is:
A bit is a single on/off value. Only these two values are possible.
The two values may go by different names, such as true/false, or 1/0. There are many ways in which a bit can be implemented. Here are some ways that bits are implemented:
The implementation of bits is different in main memory and secondary memory, but logically, both types of memory store information represented as bit patterns.
(Thought question:) Does the information change when a bit is copied from one form of storage to another? For example, does the information change when a bit implemented as a voltage level on a wire is copied to a tiny part of a disk?