Mark 1 Computer
The first electro- Mechanical computer Mark 1 was built in the early 1940s which was based on the principle of Charles Babbage by Howard Aiken.
This project was a joint partnership between IBM and Harvard University It was also called IBMASCC (International Business Machine Automatic Sequence Control Calculator) this is the first programmable digital computer (Mark 1).
Mark 1 was constructed by using switches relays rotating shafts and clutches it was very complex in design as it contained about 7500 parts and about 500 miles of wire was used to connect them the machine was very heavy and its dimension was 51 feet long 8 feet tall and 3 feet wide It had a 50 feet rotating its length turned by a 5 horsepower electronic motor It consumed a lot of electricity and emitted a lot of heat.
Grace Hopper is one of the programmers for mark 1 she found the first computer “bug”: a month that had gotten into the paper tape and whose wings were blocking the reading of the holes.
ABC (Atanasoff-Berry computer)
John Vincent Atanasoff was a professor of physics and mathematics at Lowa State University with the help of his graduate student Clifford Berry he built a machine that could solve different types of mathematical problems successfully tested in 1942.
This machine was the first to store data as a charge on a capacitor which is how today’s computers store information in their main memory (RAM) It also used vacuums tubes and capacitors for the storage of electricity.
Z2
Konrad Zuse completed the Z2 electromechanical computer in 1940. It was an improvement on the Z1 Zuse built by his parents, which used the same mechanical memory. For the Z2, he replaced the arithmetic and control logic with 600 electrical relay circuits, weighing over 600 electrical relay circuits, weighing over 600 pounds.
After that, he kept going on doing the improvement on the Z2 and made different versions of the computer and named Z3, Z4, Z5, and Z11 (Zuse 11 was the commercial electromechanical computer developed in 1955.