Computer memory

Now, we are going to introduce the concept of memory, the mechanism that holds programs and data. Real or physical memory is implemented as DRAM, flash memory, and disk drives. This memory is part of a computer’s hardware. We do not cover physical memory in this book. Instead, we will discuss abstract memory and how it is modeled by Python. This is the programmer’s view of memory.

All data is stored in physical memory, and all the data structures designed by a programmer must be mapped onto physical memory. The mapping process is the job of the operating system, and this book does not deal with the translation of abstract memory addresses into real memory addresses.

Consider the following Python list:

friends = ['John', 'Jenny', 'Rumpelstiltskin']

These three strings have the [0], [1], and [2] addresses in the friends list. The operating system maps these elements onto the physical memory storage locations. These...