## Early Counting Devices

People learned how to count well back in the Stone Age. At this early period, counting devices used were fingers, stones, wooden sticks, pebbles, cowries and notch sticks.

These devices were used in counting, and in the performance of simple arithmetic calculations such as the addition of numbers, subtraction, and multiplications.

Until now, some of these early counting devices are in use in some areas. However, this simple way of counting was difficult to use for large counts because of their awkward nature. The methods were used until the invention of the Abacus device.

### Problems of early counting devices

- They cannot be used to count large numbers
- They are limited in scope and cannot go beyond a particular number
- There is a problem of non-accuracy when used to count large numbers
- Using them to count large numbers could bring confusion as counting progresses

## Mechanical Counting and Calculating Devices

### Abacus

When trading between countries became important, people needed more sophisticated devices. The Abacus device was invented to replace the traditional method of counting.

The abacus device is an instrument used for counting as far back as 500 B.C. with the objective of making calculations easier, and to suit the various number systems.

In the beginning, the abacus was just a board with stones or sticks. On the surface of the abacus, there were parallel notches or grooves.

People made calculations by moving stones, sticks, bones. If numbers are to be added, stones were added, if subtraction is to be made, stones were taken off. If it were multiplication, double summing was made. When dividing, double subtraction was performed.

There are different types of abacus counting device including the Chinese abacus called *Suanpan*, invented in the 6^{th} century, the Roman abacus, named as *Calculi* or *Abaculi, and the *Japanese abacus, called *Soroban.* Soroban was used in the 16^{th} and 17^{th} century.

In China, pearls or bullets substituted stones and these were put into wire or string.

The Roman abacus was made of bronze, stone, ebony or colored glass.

### Slide Rule

In 1620, William Oughtred developed a counting device called *slide rule*. This invention was necessitated by the invention of logarithms and Napier’s bones.

This device makes use of a cursor, which is moved up and down various scales to perform multiplication and division using the principles of Logarithms. Thus, the device is equivalent to today pocket calculator.

*Mechanical Counting Devices*## Electro-Mechanical Counting Devices

### Napier’s bones

In 1617 John Napier, a Scottish mathematician, invented the Napier’s bones. These were rods on which numbers were marked.

These numbers enable the user to easily work out the answers to a restricted set of the multiplication tables. The numbers to be multiplied are positioned on the top row and the left column.

The answer is obtained at the interoperation of these two. Napier later invented tables of Logarithms which enabled multiplication and division to be carried out very simply by addition and subtraction.

### Blaise Pascal Machine

In 1642 Blaise Pascal invented the first calculating machine when he was 19 years old. This machine was developed to assist his father’s work as a government auditor of accounts.

The machine consists of clogged wheels, gears, and dials. Each wheel was divided into ten sections, representing numbers, and the mechanism allowed a carry from one wheel to the next.

This principle is still in use today. Odometers in cars use Pascal’s wheel principle to keep track of the number of kilometers traveled.

The machine had input, processing and output devices. Basically, the Pascal machine was only capable of addition.

### Gottfried Leibniz Machine

A famous German mathematician, Gottfried Von Leibniz made the most significant contribution to the mechanical calculator in 1671 when he invented the Leibniz calculating machine.

The machine can perform 4 arithmetic operations. The machine also used a wheel with teeth on them, termed “steeped wheel”, which allowed long multiplication and division to be done.

The process of multiplication involved repeated addition. Unfortunately, Leibniz’s machine was unreliable, as were most of the early calculators.

Because of this problem, mechanical calculators were not popular for many years, and it was not until the late nineteenth century that they became widely used in business.

### Joseph Jacquard Loom

The Jacquard loom is a mechanical loom, invented by Joseph Marie Jacquard in 1800. The loom simplifies the process of manufacturing textiles with complex patterns such as brocade, damask, and matelasse.

In 1725, French weaver, Basile Bouchon constructed a weaving loom that could be controlled by holes in a roll of paper. The holes allowed some needles in the loom to be engaged, while others were held back.

The loom was, therefore “programmed” by the placement of the holes in the roll of paper to produce a particular pattern. However, in Bouchon’s loom, someone had to be employed to control the needles and decide which would be used for each line of weave in the fabric.

But Joseph-Marie Jacquard improved upon Bouchon’s design by developing a loom which used a punched card to control each line of the weave. Over 1000 needles could be controlled at one time, and very intricate designs were easily created.

### Charles Babbage Analytical machine

Charles Babbage was a mathematics professor at Trinity College in Cambridge, England. After several unsuccessful attempts at building a mechanical calculating machine, Babbage developed the analytical engine in 1834.

Babbage’s designs were similar to the general design of modern-day computers, including a central arithmetic unit for calculating, called a mill, an area for retaining numbers, called a store, and sophisticated methods for input and output.

While working on his analytical engine, Babbage began a lengthy correspondence with poet Lord Byron’s daughter, Ada Augusta, Countess of Lovelace.

Lady Lovelace became fascinated with Babbage’s ideas, and in her analysis of his analytical engine, she developed the essential ideas of programming, such as “branching” to perform decisions and repetitions.

Because of her work in this area, she is considered to be the first computer programmer. The programming language “Ada” is named after her.

### Philip Emeagwali

Philip Emeagwali is a Nigerian-born engineer and computer scientist/geologist. He is called the Bill Gates of Africa. He invented the world’s fastest computer. He was one of two winners of the 1989 Gordon Bell Prize, a prize from the IEEE, for his use of a Connection Machine supercomputer to help analyze petroleum fields.

He programmed the Connection Machine to compute a world record 3.1 billion calculations per second using 65,536 processors to simulate oil reservoirs. He has submitted over 41 inventions to the US patent and trademark office.

*Images of Electro-Mechanical Counting Devices*## Electronic Counting Devices and Modern Computer

### Herman Hollerith Punch Cards

The rest of the nineteenth century witnessed the design of more complicated mechanical devices. By 1890, an American called Dr. Herman Hollerith made the most outstanding and important invention called punch cards.

The machine was used to process information obtained in the census of the population carried out in the United States in 1890. With this machine, he was able to achieve in three years what will take seven years to do manually.

Hollerith used Jacquard’s punched-card idea to feed personal statistics into his machine. Holes in the punched cards stood for a person’s age, sex, state, and other similar information. There was one card for each person.

As each card was fed into the machine, a set of metal pins were brought down on the card. The pins passed through any holes punched in the card, which completed an electrical circuit which turned a counter dial.

To sell the machine, Hollerith formed his own company in 1896, then later merged with several other companies to form the Computing Tabulating Recording Company (CTR) in 1911. CTR later became the International Business Machines or IBM.

### John Von Neumann Machine

In 1945, the Hungarian born American mathematician, John von Neumann undertook a study of computation. In this study, he demonstrated that a computer could have a simple, fixed structure, yet be able to execute any kind of computation if given properly programmed control, and without the need for hardware modification.

Von Neumann contributed a new understanding of how practical fast computers should be organized and built; these ideas, often referred to as the stored-program technique, became fundamental for future generations of high-speed digital computers and were universally adopted.

The principal feature of a von Neumann machine is that the program and any data are both stored together, usually in a slow-to-access storage medium such as a hard disk, and transferred as required to a faster, and more volatile storage medium (RAM) for execution or processing by a central processing unit (CPU).

Since this is practically how all present-day computers work, Neumann is termed the *father of the modern computer. *

The term “von Neumann architecture” is rarely used now, but it was a common parlance in the computing profession through to the early 1970s.

*Von Neuman Architecture*Prior to Neumann’s idea, programs were viewed as essentially part of the machine, and hence different from the data the machine operated on. A common approach was to input the program by some physical means, such as wiring a plugboard, and then feeding in the data for the program to act upon.

As a result of Neumann’s discovery, computing and programming became faster, more flexible, and more efficient, with the instructions in subroutines performing far more computational work.

In 1945, von Neumann proposed the stored program concept in his report on the EDVAC. He did it together with computer pioneers, J. Presper Eckert, John Mauchly, Arthur Burks, and Hermann Goldstine, who was working on plans for the EDVAC.

According to the original papers proposing the new architecture, a von Neumann computer has five parts: **an arithmetic-logic unit, a control unit, a memory, some form of input/output, and a bus** that provides a data path between these parts. Such a computer operates by performing the following sequence of steps:

- Fetch the next instruction from memory at the address in the program counter.
- Add the length of the instruction to the program counter.
- Decode the instruction using the control unit.
- Go back to step 1.

Von Neumann computers have some drawbacks. In particular, they carry out instructions one after another, in a single linear sequence, and they spend a lot of time moving data to and from the memory. This slows the computer. This problem is called the *von Neumann bottleneck*.

### Modern machines

The EDVAC computer, when it was finally constructed in 1952, followed von Neumann’s design. But the first von Neumann computer to be constructed and operated as the Manchester Mark I.

*Manchester Mark 1*This machine was designed and built at Manchester University in England. It ran its first program in 1948. The computer had a 96-word memory and executed an instruction in 1.2 milliseconds. Today, the computer you are using is born out of von Neumann’s idea.