Social Science - Quiz 13 - Pg. 28-30

When the EDVAC computer replaced the ENIAC computer, what technology did delay lines replace?

• vacuum tubes

• punch cards

• transistors

• electric relays

• cathode ray tubes

Answer explanation

At the same time computer processors were developing, computer memory was also getting more efficient. The ENIAC computer used vacuum tubes for memory storage. However, when the ENIAC team developed their follow-up EDVAC computer, they decided to use the more efficient delay line technology for the memory storage. [28,3]

Which liquid typically filled delay lines?

• rubidium

• cesium

• gallium

• mercury

• bromine

Answer explanation

A delay line is a metal tube with liquid (typically mercury) inside. When an electrical current is passed through the mercury, it causes vibrations and sends a signal. The signal is read at the other end of the tube. Unfortunately, the use of mercury in the delay lines also made them difficult to make and dangerous to handle. [28,3]

According to its design, how long did the column of liquid in the EDVAC computer need to be?

• two feet

• three feet

• four feet

• one foot

• five feet

Answer explanation

Delay lines were used in many early computers. The EDVAC computer design (one that utilized delay lines) required a five foot column of mercury that could hold roughly one thousand bits of memory. [28,3]

Around how many bits of information could a delay line in an EDVAC computer store?

• five thousand

• three hundred

• one hundred

• five hundred

• one thousand

Answer explanation

The delay line in the EDVAC computer called for a five foot long column of mercury, which could store around one thousand bits of memory. [28,3]

Which advantage did delay lines have over its predecessor?

• greater reliability

• less risk during manufacturing

• lower toxicity

• use of fewer electronics

• more adaptability to different temperatures

Answer explanation

The predecessor of delay lines were vacuum tubes. Delay lines did use vastly fewer electronics than vacuum tubes. However, they were also highly toxic (because they usually contained mercury) and needed to be kept at high temperatures to work. [28,4]

Which computer was the first stored-program computer?

• UNIVAC

• IBM 650

• Manchester Baby

• ENIAC

• Colossus

Answer explanation

The first stored-program computer was called the Manchester Baby. It was used to test the feasibility of Williams tubes for the purpose of memory storage. [29,1]

Which technology is similar in function to the Williams tubes?

• cathode-ray tube

• magnetic tape

• vacuum tube

• delay line

• microprocessors

Answer explanation

A Williams tube fires a stream of electrons again and again through the tube towards a phosphorescent surface, creating a pattern. This is similar to the way cathode-ray tubes work in old television sets. Delay lines and vacuum tubes have a similar purpose to Williams tubes, but they do not have a similar function. [29,1]

Which word correctly describes the surface at which the stream of electrons are fired in a Williams tube?

• cloudy

• transparent

• phosphorescent

• bulky

• opaque

Answer explanation

In a Williams tube, a stream of electrons are fired at a phosphorescent surface at the end of the tube. This creates a visible pattern and works as memory storage. [29,1]

Which computer used the Williams tube as part of its memory hardware?

• IBM 705

• IBM 7090

• IBM 701

• IBM 704

• IBM 709

Answer explanation

The computers IBM 701 and IBM 702 utilized Williams tubes as their memory storage. Later, when IBM released the new and improved computers IBM 704 and IBM 705, they used core memory technology. [29,1]

Why was the memory storage system magnetic drum memory considered slow?

• reliance on moving parts

• high production costs

• lack of technological advancements

• incompatibility with other storage systems

• insufficient storage capacity

Answer explanation

Magnetic drum memory technology involves a metal drum with a magnetic coating rotating several hundred times a minute. They were reliable but were considered slow because they relied on moving parts (the rotating drum). [29,2]