Plyojump - Computer History

Computer History - Mainframe Era (1944-1978)

ENIAC (1944)

ENIAC, short for Electronic Numerical Integrator And Computer, was the first large-scale, electronic, digital computer capable of being reprogrammed to solve a full range of computing problems. ENIAC was designed at the University of Pennsylvania to calculate artillery firing tables, but was stands as the first modern digital computer. It was designed and built by John Mauchly and J. Presper Eckert of the University of Pennsylvania. Interestingly, all the programmers were female, Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman.

Programmers Betty Jean Jennings (left) and Fran Bilas (right) operate the ENIAC's main control panel at the Moore School of Electrical Engineering.


Programming ENIAC

eniac with programmers


Internal wiring of ENIAC

ENIAC wiring

More on the ENIAC (Wikipedia)

IBM SSEC (1948)

This image show the gigantic size of early electronic digital computers. Often, their design seems a little like a temple, with the terminal like an altar for the "high priests" - the programmers - to work.



The Artificial Intelligence dream starts early!

Tom Watson Time Magazine

The cover of Time magazine showing Tom Watson, head of IBM in the 1950s

Univac (1951)

The UNIVAC I was the world's first commercial computer, delivered to the U.S. Census Bureau in 1951.


Grace Hopper

Grace Hopper with fellow programmers, early 1950s


The SAGE Computer Network (about 1954)

IBM’s SAGE(Semi-Automatic Ground Environment) is a large semi-automated air defense system created in the early 1950s for real-time analysis of radar data.

The machine weighed 300 tons and occupied one floor of a concrete blockhouse. It have had Dual Processor: one on line and other trainning, maintenance and hot backup. It costed aproximately $10 billion in 1954 dollars. At its peak, the project employed 20% of the world's programmers. Users interacted witht he system via a "light pen" - they drew directly onto the computer screen.

SAGE Computer sage lightpen

1950s Mainframes

1950s mainframe

RAMVAC - first computer with a hard drive


CDC 6600 (late 1950s)

Control Data Corporation’s 6600 machine was designed by noted computer architect Seymour Cray, who later created the Cray supercomputers of the 1980s and 1990s. It was the fastest computer in the world during the 1960s. A CDC computer was used to implement the first real-time computer game, Spacewars, at MIT at the end of the 1950s.

CDC 6600 DEC PDP 1

The Dec 6600ran the first real-time video game, called SpaceWar, and (linked to an electric typewriter for output) the first word processor program.


SABRE Reservation system (1960)

An outgrowth of the SAGE miltary computer system for tracking aircraft, SABRE was the first commercial computer-based airline reservation system when it came online in 1962. A version of this system is still used to handle airline reservations today.

Sabre reservation system



The IBM 360 (1960s)

Many mainframe models were developed by IBM in the 1950s and 1960s, but the IBM 360 is particularly important, since it was the first mainframe to enjoy widespread use in business and government. Large numbers of men and women sought careers in computers and data processing during this era.

ibm 360

ibm 360


An IBM 360 mainframe in use, compared to a Hollerth calculator on the right. Images from this era show lots of women for two reasons. First, new business environments often don't have gender rules prebuilt, so it wasn't obvious that a woman couldn't work with computers, even program. Second, entering data and managing software was seen as inferior to creating hardware, an exclusively male profession at the time. Today, the relative values of hardware and software are reversed.

Computing in the 1960s

Some images of Univac computers from the 1960s. Note the use of female models. This is not just advertising - computer programming and data processing became a common career path for young women in the 1960s. As with the telegraph 100 years earlier, they encountered less prejudice in "high tech" industries.
univac 1065 Univac 1965

PDP ad

Timesharing and "Dumb Terminals"

By the 1960s a model for computing had emerged featuring a centeral computer with a large set of "dumb" terminals. This allowed many people to use the mainframe at the same time, and caused an enormous expansion of the computing community. The scenes resemble a data center today, but remember that there is only one computer here, connected to a large number of screens. Single-person computers (or "personal" computers) did not become widespread until the 1980s.

The left image show IBM computers being used to manage airline reservatons in a timeshare environment. The larger machines on the left are microfilm readers, which substituted for computers for many years. The other images show examples of "dumb" terminals, along with a typical text-based computer interface of the era.

IBM mainframe airline reservationVT 100 terminal dumb terminalTimesharing

Timeshare computers at a college in the 1960s, with an older punched-card interface.


Apollo Guidance Computer (1968)

This computer was used to guide the Apollo lander to the surface of the moon. It was also used in other NASA spacecraft of the 1970s, including Skylab. Moon "hoaxers" sometimes claim that moon landings were impossible due to lack of computers. In reality, powerful computers were available by the mid-1960s - they were just too expensive for ordinary people to own.

Apollo Computer interface Apollo Guidance Conputer LEM

Transcript of the first lunar landing (including reboots of the guidance conputer)

A software simulation of the AGC you can download!

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