Stored-program computer

Old computers were hard to change. You had to move plugs or tape.

A new kind of computer was built. It keeps its rules in its memory. This is called a stored program.

One early machine was called the Baby. It ran its first rule in 1948.

Some machines use one memory for everything. Other machines use two separate memories. This helps them work.

These machines changed how we use tools. They can now do many different jobs. It is a very smart way to work.

Old computers were hard to change. You had to move plugs or tape.

A new kind of computer was built. It keeps its rules in its memory. This is called a stored program.

One early machine was called the Baby. It ran its first rule in 1948.

Some machines use one memory for everything. Other machines use two separate memories. This helps them work.

These machines changed how we use tools. They can now do many different jobs. It is a very smart way to work.

Most early computers could not change tasks easily. Some used a single hardwired program. Others used punched tape. You had to feed the tape into the machine. Some used plugs and switches to work.

A stored-program computer is different. It keeps its instructions in memory. This memory can be electronic or optical. This means it uses light.

There are two main ways to build these. One is called von Neumann architecture. This type uses one memory for both rules and data. The other is called Harvard architecture. This type uses two separate memories. One memory holds the rules. The other holds the data.

The Manchester Baby was a very important machine. It was the first electronic computer to run a stored program. It did this on June 21, 1948. Later, the Ferranti Mark 1 became the first to be sold in stores. In 1953, the first transistor-based computer also began to work. This used tiny parts to run programs.

A stored-program computer is a very special kind of machine. It keeps its instructions inside its own memory. This memory can be electronic, magnetic, or even optical. Optical means it uses light to read information. Before this, computers were much harder to use. People had to use plugboards or switches to change tasks. Some machines used punched tape to follow rules. You had to feed the tape into the machine physically. This made it difficult to switch between different jobs.

There are two main ways these computers work. One way is called the von Neumann architecture. In this design, the computer uses one memory for everything. It stores both the program rules and the data together. The other way is called the Harvard architecture. This design uses two separate memories to stay organized. One memory holds the program instructions. The other memory holds the data the program uses.

Scientists have worked on these ideas for a long time. The idea began with a concept called a universal Turing machine in 1936. A man named Konrad Zuse also had a similar idea. In 1936, he filed patents for storing instructions in memory. Later, John von Neumann shared these ideas with his team. Many early machines were not like this at all. The Atanasoff-Berry computer could only run one single program. It did not have any way to store different instructions.

Many famous computers helped prove these ideas worked. The Manchester Baby was a very important machine. It ran its first stored program on June 21, 1948. It was built at the University of Manchester. Another machine called the EDSAC ran its first program in Cambridge on May 6, 1949. In the United States, the BINAC was delivered on August 22, 1949. The first computer built in Europe was the MESM in 1950.

These inventions changed how we use technology every day. They led to the first computers you could actually buy. The Ferranti Mark 1 was the first one sold in 1951. Later, machines like the IBM 650 were made in large numbers. By 1953, the first transistor-based computer was also working. These machines even helped improve how we make phone calls. This helped create the electronic switching systems we use now.

A stored-program computer is a machine that holds its instructions in memory. This memory can be electronic, electromagnetic, or optical. This design is different from older systems. Those older systems used plugboards or physical switches to function. In a stored-program computer, the instructions are treated the same as data. This means the machine can access both using the same methods. This flexibility allows computers to change tasks much more easily.

There are two main ways to organize this memory. One is called the von Neumann architecture. In this system, the computer stores program data and instructions in the same memory. The other is the Harvard architecture. This design uses separate memories for program instructions and for data. Some people use the term "stored-program computer" to mean the von Neumann architecture. However, historians note that early Harvard machines were once seen as reactionary.

The idea for these machines began with theoretical concepts. In 1936, the idea of a universal Turing machine was introduced. John von Neumann knew about this work and shared it with his team. Around the same time, Konrad Zuse filed two patent applications. He suggested that machine instructions could stay in the same storage used for data. This was a major shift from early machines like the Atanasoff-Berry computer. That machine was hardwired to do only one single task.

Early programmable machines were still very physical. The Zuse Z3 and the Harvard Mark I used punched tape. You had to feed the tape into the system to run it. The Colossus computer required people to move physical switches and plugs. These methods were slow compared to modern memory. The transition to electronic storage changed everything for computing.

Several machines claim the title of the first stored-program computer. The Manchester Baby is a famous example from the University of Manchester. It successfully ran a stored program on 21 June 1948. It was a proof of concept for the Manchester Mark 1. The EDSAC in Cambridge also ran its first program on 6 May 1949. In the United States, the BINAC was delivered on 22 August 1949. The MESM was the first such computer built in continental Europe in 1950.

Other machines were also part of this early era. The IBM SSEC became operational in January 1948. It was an electromechanical machine with a complex memory system. The ENIAC was modified in April 1948 to store programs. It used dials in function tables to store 3,600 decimal digits. The ARC2, developed at Birkbeck, University of London, used a rotating drum for storage. These various designs helped researchers understand how to manage digital information.

As the technology matured, computers became available for purchase. The Ferranti Mark 1 was the first commercial electronic digital computer in 1951. Later, machines were produced in much larger numbers. The Bull Gamma 3 sold about 1,200 units starting in 1952. The IBM 650 sold about 2,000 units starting in 1953. By November 1953, the first transistor-based stored-program computer was operational.

Stored-program technology even changed how telephone calls are made. This is known as stored program control, or SPC. Erna Schneider Hoover began designing these systems at Bell Labs around 1954. These systems used a flying-spot store to hold instructions. This was a photographic plate read by an optical scanner. It could access information in about one microsecond. This allowed for the first electronic switching systems in telecommunications.