Stored program concept

There are two main types of computer systems:

• general-purpose computers - which use the stored program concept
• embedded systems

General-purpose computers are designed to be able to run loads of different things - depending on the programs we install and run on them. Because they store a program which they run, we often call these stored program computers.

In a stored program computer, instructions are stored in main memory.
Instructions are fetched, decoded and executed one-by-one (serially) by the processor.
Programs can be moved in and out of main memory.

Types of stored program architecture

Based on the way the instructions and data are laid out in memory, we can categorise stored program architectures into two main types:

• von neumann architecture
• harvard architecture

Memory storage

Because we need to store the instructions and the data somewhere, we need a way to lay out the memory. This is where addressable memory comes in. We can give each byte (or group of bytes) in memory a unique address, and we can use those addresses to read and write data to certain locations in memory.

flashcards