RAM: a form of temporary internal storage whose contents can be retrieved
and altered by the user; also called "read and write memory." (The acronym,
RAM, remains in common usage, although the term "random access
memory" does not.)
d. First-Generation Stored Program Computers (1947). The first generation
of modern programmed electronic computers appeared in 1947. These machines had
punched-card or punched-tape input and output devices and RAMS of 1,000-word
capacity. Physically, they were more compact than ENIAC; some were about the size
of a grand piano and used 2,500 electron tubes, far fewer than required by the earlier
computers. They needed considerable maintenance, attained perhaps 70 to 80 percent
reliability, and were used for 8 to 12 years. This group of machines included EDSAC,
EDVAC and UNIVAC.
(1) Electronic Delay Storage Automatic Computer (EDSAC) (1949) was the
first computer to incorporate the ideas outlined by Von Neuman. Von Neuman's historic
report caused a furor in the computing world. ENIAC, the world's first high-speed
calculating device, had just been developed and now, at essentially the same time, or.
Von Neuman proposed an entirely new machine. Built at Cambridge University in 1949,
EDSAC was no faster than ENIAC, but it did utilize the binary number system and
instructions that were stored internally. These instructions were called a program, thus
the name "stored program."
(2) Electronic Discrete Variable Automatic Computer (EDVAC) (1952), a
computer similar to EDVAC, was the second machine designed by the Eckert-Mauchley
team. EDVAC was smaller, faster, more versatile, and more flexible than ENIAC.
Figure 1-19. EDSAC, the first computer that stored its own programs.