Computer memory hierarchy

Evolutionary progress can be illustrated with computer memory. The computer memory is represented by Random-access memory modules. These chips turn into useful hierarchically controlled memory once the computer is turned on:

• The CPU takes over control about all the electronic processes in those memory chips.
  • First the BIOS is loaded from an other memory chip on the mainbord.
    • Once in the memory the BIOS allows to load the operating system (OS) from an external memory device (hard-disk, USB, CD, or DVD)
      • The OS launches further device drivers for additional hardware
        • The OS also launches applications (word-processor, music player and so on)

The evolution of computer hardware and software is characterized by increasing complexity and hierarchy.

• The first 'computers' didn't even distinguish between memory and processor. Computers evolved from adding machines with only a very restricted capability to store and process data.
• When the first computer was invented there wasn't even an operating system.
• The first operating systems handled only one program and a limited set of devices.
• As the number of peripherals (printer, hard-disk, scanner and so on) the operating got the task to decide which driver has to be invoked when.
• As more an more programs appeared, the operating systems had to learn multitasking.
• The most recent advancement was the evolution of hierarchy controlled through Internet connections. (Whether desired or hated, it just happens.)