# Harvard Mark I

> early American computer

**Wikidata**: [Q776823](https://www.wikidata.org/wiki/Q776823)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Harvard_Mark_I)  
**Source**: https://4ort.xyz/entity/harvard-mark-i

## Summary
The Harvard Mark I was an early American electro-mechanical computer developed by IBM and designed by Howard H. Aiken. It was one of the first programmable computers, weighing 4.3 tonnes and entering service on August 7, 1944.

## Key Facts
- Designed by Howard H. Aiken, a pioneer in computing and physicist/mathematician
- Manufactured by IBM and owned by Harvard University starting August 7, 1944
- Weighed 4.3 tonnes (4,300 kg)
- Classified as an electro-mechanical computer and one-of-a-kind computer
- Also known as Automatic Sequence Controlled Calculator (ASCC) and IBM Automatic Sequence Controlled Calculator
- Served as the predecessor to the Harvard Mark II
- Entered service in 1944 and was one of the earliest programmable computers

## FAQs
### Q: What was the Harvard Mark I?
A: The Harvard Mark I was an early American electro-mechanical computer developed by IBM and designed by Howard H. Aiken. It was one of the first programmable computers, weighing 4.3 tonnes and entering service on August 7, 1944.

### Q: Who designed the Harvard Mark I?
A: The Harvard Mark I was designed by Howard H. Aiken, a pioneer in computing who was also a physicist, mathematician, and inventor. Aiken was the original conceptual designer behind IBM's Harvard Mark I computer.

### Q: When was the Harvard Mark I built and by whom?
A: The Harvard Mark I was built by IBM and entered service on August 7, 1944. It was owned by Harvard University and represented a significant advancement in early computing technology.

## Why It Matters
The Harvard Mark I represents a pivotal moment in the history of computing as one of the first large-scale automatic digital computers. Developed during World War II, it demonstrated that complex calculations could be automated using electro-mechanical components, paving the way for modern digital computing. The machine could perform three additions per second and was used for scientific calculations, including work on the Manhattan Project. Its development marked the beginning of the transition from human "computers" performing calculations by hand to automated machines capable of processing information at unprecedented speeds. The Harvard Mark I also established important precedents for computer architecture and programming that influenced subsequent computer designs.

## Notable For
- One of the first programmable computers ever built
- Weighed 4.3 tonnes, making it one of the largest early computers
- Designed by Howard H. Aiken, a pioneer in computing
- Manufactured by IBM, marking the company's entry into computer development
- Served as the predecessor to the Harvard Mark II, continuing the evolution of early computing

## Body
### Technical Specifications
The Harvard Mark I was an electro-mechanical computer that measured 51 feet long, 8 feet high, and 2 feet deep. It contained approximately 3,000 relays and 1,400 mechanical switches, with data stored on punched paper tape. The machine could perform three additions per second and had a memory capacity of 72 numbers.

### Development and Design
Howard H. Aiken, a Harvard professor, conceived the idea for the Mark I in 1937 and approached IBM for funding and construction. The project was approved by IBM in 1939, and construction began in 1939, taking approximately 5 years to complete. The machine was officially presented to Harvard University on August 7, 1944.

### Operational History
The Harvard Mark I was used primarily for scientific calculations, including work on the Manhattan Project during World War II. It operated continuously for 15 years until it was retired in 1959. The machine was programmed using punched paper tape and could perform addition, subtraction, multiplication, and division operations.

### Legacy
The Harvard Mark I established important precedents for computer architecture, including the use of a control unit, arithmetic unit, and memory. It influenced the development of subsequent computers and helped establish the field of computer science. The machine is now preserved at the Harvard Collection of Historical Scientific Instruments.

## References

1. Grace Hopper and the Invention of the Information Age
2. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
3. Freebase Data Dumps. 2013
4. National Library of Israel