Stored-program computer

Stored-program computer refers to a computer design model that primarily operates by storing program instructions and data in a read-write memory. This concept is fundamental to modern computing and underpins the architecture of most contemporary computers. The stored-program concept was a significant departure from earlier computing machines, which were programmed through physical rewiring or setting of switches. The idea of a stored-program computer was first introduced by mathematicians and computer scientists John von Neumann, Alan Turing, and others in the mid-20th century.

History

The concept of the stored-program computer was developed in the 1940s. One of the earliest implementations of this concept was the Electronic Delay Storage Automatic Calculator (EDSAC) at the University of Cambridge in 1949, closely followed by the Manchester Small-Scale Experimental Machine (SSEM) or "Baby," which ran its first program in 1948. These machines demonstrated the practicality and advantages of storing instructions in memory rather than hard-wiring them.

Architecture

The architecture of a stored-program computer is based on the principle that instructions and data are stored in a Random Access Memory (RAM) or other forms of digital memory. This architecture is often referred to as the Von Neumann architecture, named after John von Neumann, who was instrumental in its development. The key components of this architecture include:

• Central Processing Unit (CPU): Executes instructions from memory.
• Memory: Stores both data and instructions.
• Input/Output (I/O) devices: Allow the computer to communicate with the external world.
• Control unit: Directs the operation of the processor and its interaction with memory.

Advantages

The stored-program concept offers several advantages over previous computing models:

• Flexibility: Computers can easily switch between tasks by loading different programs into memory.
• Speed: Eliminates the need for time-consuming reconfiguration of hardware for each new program.
• Complexity: Supports more complex and powerful software applications.

Impact

The stored-program computer has had a profound impact on the development of computing technology. It laid the groundwork for the development of modern computers and programming languages. Additionally, it enabled the creation of complex software systems and the growth of the digital economy.

See Also

• Computer architecture
• Von Neumann architecture
• Alan Turing
• John von Neumann
• EDSAC
• Manchester Small-Scale Experimental Machine