1. Digital Information Technology
History of Computers!
Digital Information Technology

2. Objective
Students will understand how the computer was evolved over many years.
As technology develops the computers through different phrases.
Student will learn the key people in the history of computer development.
Students will understand the trends of computer development and forecast the future of computers.

3. Phases of Computer History
Phase 1: Mechanical
Phase 2: Vacuum Tubes
Phase 3: Transistors and Integrated Circuits
Phase 4: Microprocessors
Phase 5 Network and Wireless
Phase 6: Artificial Intelligence

4. Prehistoric Computers
Counting with hands
Abacus
Astrolabe
The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task.

5. Before Calculators… Napier Bones (1632) Slide Ruler
Led directly to the invention
Slide Ruler
Was still used in the 1960’s space program.
Mercury
Gemini
Apollo
Apollo 11 landed on the moon in 1969.
Napier's invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.

6. Early Calculators Leonardo da Vinci drawing of a computer
William Schickard (1623) A gear driven calculating clock.
Blaise Pascal (1642) Invented the Pascaline
Leonardo da Vinci ( ) made drawings of gear-driven calculating machines but apparently never built any.
The first gear-driven calculating machine to actually be built was probably the calculating clock, so named by its inventor, the German professor Wilhelm Schickard in This device got little publicity because Schickard died soon afterward in the bubonic plague.
In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one-function calculator (it could only add) but couldn't sell many because of their exorbitant cost and because they really weren't that accurate (at that time it was not possible to fabricate gears with the required precision). Up until the present age when car dashboards went digital, the odometer portion of a car's speedometer used the very same mechanism as the Pascaline to increment the next wheel after each full revolution of the prior wheel. Pascal was a child prodigy. At the age of 12, he was discovered doing his version of Euclid's thirty-second proposition on the kitchen floor. Pascal went on to invent probability theory, the hydraulic press, and the syringe. Shown below is an 8 digit version of the Pascaline, and two views of a 6 digit version:

7. Phase 1: Mechanical Joseph Marie Jacquard : (1801) Jacquard Loom
Use of punched cards.
Charles Babbage: (1822) Steam driven calculating machine Difference Engine.
Very large, extremely heavy, very costly
Not accurate
In 1801 the Frenchman Joseph Marie Jacquard invented a power loom that could base its weave (and hence the design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long row by rope. Descendents of these punched cards have been in use ever since (remember the "hanging chad" from the Florida presidential ballots of the year 2000?).
By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. This machine would be able to compute tables of numbers, such as logarithm tables. He obtained government funding for this project due to the importance of numeric tables in ocean navigation. By promoting their commercial and military navies, the British government had managed to become the earth's greatest empire. But in that time frame the British government was publishing a seven volume set of navigation tables which came with a companion volume of corrections which showed that the set had over 1000 numerical errors. It was hoped that Babbage's machine could eliminate errors in these types of tables. But construction of Babbage's Difference Engine proved exceedingly difficult and the project soon became the most expensive government funded project up to that point in English history. Ten years later the device was still nowhere near complete, acrimony abounded between all involved, and funding dried up. The device was never finished.

8. Tabulating Machine Herman Hollerith: (1880) Tabulating Machine
Prior USA census will take 7 ½ years to complete. With Tabulating machine it was completed in 9 months.
Use of punch cards
The next breakthrough occurred in America. The U.S. Constitution states that a census should be taken of all U.S. citizens every 10 years in order to determine the representation of the states in Congress. While the very first census of 1790 had only required 9 months, by 1880 the U.S. population had grown so much that the count for the 1880 census took 7.5 years. Automation was clearly needed for the next census. The census bureau offered a prize for an inventor to help with the 1890 census and this prize was won by Herman Hollerith, who proposed and then successfully adopted Jacquard's punched cards for the purpose of computation.
Hollerith's invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal's mechanism which we still see in car odometers), and a large wall of dial indicators (a car speedometer is a dial indicator) to display the results of the count. Hollerith built a company, the Tabulating Machine Company which, after a few buyouts, eventually became International Business Machines, known today as IBM.

9. Phase 2: Vacuum Tubes Mark I: (1944) 1st programmable computer.
Developed by Harvard and IBM
Use of a 5 hp electric engine, 500 miles of wire, 8 ft. tall, and 51 ft. long.
It ran non-stop for 15 years.
Mark 1 stopped once relays were stuck
Grace Hopper “debugged” the computer.
Howard Aiken, one of the developers, said that the United States would need 6 Mark 1s to handle the data needs for the country.
One early success was the Harvard Mark I computer which was built as a partnership between Harvard and IBM in This was the first programmable digital computer made in the U.S. But it was not a purely electronic computer. Instead the Mark I was constructed out of switches, relays, rotating shafts, and clutches. The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor. The Mark I ran non-stop for 15 years, sounding like a roomful of ladies knitting. To appreciate the scale of this machine note the four typewriters in the foreground of the following photo

10. Other Vacuum Tube Computers
Colossus: During WWII decrypted the Germans codes. Help defeat the Germans.
ENIAC : Electronic Numerical Integrator and Calculator
Another candidate for granddaddy of the modern computer was Colossus, built during World War II by Britain for the purpose of breaking the cryptographic codes used by Germany. Britain led the world in designing and building electronic machines dedicated to code breaking, and was routinely able to read coded Germany radio transmissions. But Colossus was definitely not a general purpose, reprogrammable machine. Note the presence of pull
eys in the two photos of Colossus below:
ENIAC: the "Electronic Numerical Integrator and Calculator" (note that it wasn't even given the name of computer since "computers" were people) [U.S. Army photo]
To reprogram the ENIAC you had to rearrange the patch cords that you can observe on the left in the prior photo, and the settings of 3000 switches that you can observe on the right. To program a modern computer, you type out a program with statements like:
Circumference = 3.14 * diameter To perform this computation on ENIAC you had to rearrange a large number of patch cords and then locate three particular knobs on that vast wall of knobs and set them to 3, 1, and 4.
Even with 18,000 vacuum tubes, ENIAC could only hold 20 numbers at a time. However, thanks to the elimination of moving parts it ran much faster than the Mark I: a multiplication that required 6 seconds on the Mark I could be performed on ENIAC in 2.8 thousandths of a second. ENIAC's basic clock speed was 100,000 cycles per second. Today's home computers employ clock speeds of 1,000,000,000 cycles per second. Built with $500,000 from the U.S. Army, ENIAC's first task was to compute whether or not it was possible to build a hydrogen bomb (the atomic bomb was completed during the war and hence is older than ENIAC). The very first problem run on ENIAC required only 20 seconds and was checked against an answer obtained after forty hours of work with a mechanical calculator. After chewing on half a million punch cards for six weeks, ENIAC did humanity no favor when it declared the hydrogen bomb feasible. This first ENIAC program remains classified even today.

11. Phase 3: Transistors and Integrated Circuits
Transistors and Integrated Circuits change computers:
Less wiring
Reduce size of computers
Reduce the price of computers
Reduce labor in assembling computers
Reduce use of electricity
Ran cooler, less down time.
With transistors and integrated circuits help develop desktop computers.
Computers had been incredibly expensive because they required so much hand assembly, such as the wiring seen in this CDC 7600:
The microelectronics revolution is what allowed the amount of hand-crafted wiring seen in the prior photo to be mass-produced as an integrated circuit which is a small sliver of silicon the size of your thumbnail

12. Phase 3: Transistors and Integrated Circuits Computers
In the 1970’s computers were much smaller than the ENIAC or the Colossus.
Computers still used punch cards, paper tape and saved files on reel to reel tape
On the right is a punch card writer.
Programs used with the computers:
FORTRAN (Math)
COBAL (Business)
LOGO (Drawing)
If you learned computer programming in the 1970's, you dealt with what today are called mainframe computers, such as the IBM 7090 (shown below), IBM 360, or IBM 370.
An IBM Key Punch machine which operates like a typewriter except it produces punched cards rather than a printed sheet of paper
University students in the 1970's bought blank cards a linear foot at a time from the university bookstore. Each card could hold only 1 program statement. To submit your program to the mainframe, you placed your stack of cards in the hopper of a card reader. Your program would be run whenever the computer made it that far. You often submitted your deck and then went to dinner or to bed and came back later hoping to see a successful printout showing your results. Obviously, a program run in batch mode could not be interactive.

13. Phase 4: Microprocessors
Altair The first desktop computer,
No Monitor
No Keyboard
No Mouse
Flip switches according a 6 inch thick manual and the lights on the front of the computer will light up with the answer.
Decode the lights from the manual.
Light is 1, not light 0
Binomial code
TV screens and keyboards came later.
Intel followed the 4004 with the 8008 and Intel priced the 8080 microprocessor at $360 dollars as an insult to IBM's famous 360 mainframe which cost millions of dollars. The 8080 was employed in the MITS Altair computer, which was the world's first personal computer (PC). It was personal all right: you had to build it yourself from a kit of parts that arrived in the mail. This kit didn't even include an enclosure and that is the reason the unit shown below doesn't match the picture on the magazine cover.
A Harvard freshman by the name of Bill Gates decided to drop out of college so he could concentrate all his time writing programs for this computer. This early experienced put Bill Gates in the right place at the right time once IBM decided to standardize on the Intel microprocessors for their line of PCs in The Intel Pentium 4 used in today's PCs is still compatible with the Intel 8088 used in IBM's first PC.

14. Phase 5 Network and Wireless Phase 6 Artificial Intelligence
Go to to continue the history of computers

15. References