· Use of vacuum tubes in electronic circuits and mercury delay lines for memory'
· Magnetic drum as primary internal storage medium
· Limited main storage capacity (1000-4000 bytes)
· Low-level symbolic language programming
· Heat and maintenance problems
· Applications: scientific computations, payroll processing, record keeping
· Cycle time: milliseconds
· Cost: $5 per floating-point operation
· Processing speed: 2000 instructions per second
TEXT 1 FIRST GENERATION COMPUTERS. HISTORY OF
DEVELOPMENT (PART 1)
1943-1947
First-generation computers were extremely large and had poor reliability. They used vacuum tubes to control internal operations, generated considerable heat, and required a lot of floor space. Although first-generation computers were much faster than earlier mechanical or electromechanical devices, they were very slow compared to today's computers, and their internal storage capacity was limited.
Punched cards were used to enter data into the computer. The holes were punched according to a coding scheme (much like Hollerith's cards), and a special-purpose machine (card reader) was used to translate them into machine language for the computer. The machine language information was often stored on magnetic drums, cylinders coated with magnetizable material, rotating at high speeds. Read/write heads suspended just above the rotating surface of the drum either wrote on the drum by magnetizing small spots or read from it by interpreting the already magnetized spots. Numbers were manipulated by the computer according to the instructions, or program, given to it. The results of these operations were punched on blank cards, which could then be read by humans.
Only binary-coded machine language was used in early computers. With hardware costs dominating the developments of first- generation computers, the use of system software to relieve the user of low-level programming was just beginning.
1943. During 1940 and 1941, Atanasoff and Berry met with John W. Mauchly and showed him their work. Mauchly, working at the Moore School of Electrical Engineering of the University of Pennsylvania, then began formulating his own ideas on how a general-purpose computer might be built. Mauchly’s ideas came to the attention of J. Presper Eckert, Jr., a graduate engineering student at the Moore School, and the team of Mauchly and Eckert w'as formed. In 1943 they designed their first electronic computer, ENIAC (Electronic Number Integrator and Calculator). It used 140 kilowatts of electricity and contained about 18,000 vacuum tubes, 70,000 resistors, and 10,000 capacitors, occupied a spmany components linked by close to a million hand-soldered connections. The I/O system consisted of modified IBM card readers and punches. ENIAC had a limited storage capacity of only 20 ten-digit numbers (it took 12 vacuum tubes to store one decimal digit), used a 100-kilohertz clock, and could perform 5000 additions or 300 multiplications per second. By today's standards, ENIAC was very slow; however, when delivered in 1946, it represented a major advance in computational power. It was instrumental, for better or worse, in bringing the wwld into the atomic age.
1945. Dr. John von Neumann recommended in a research report that the binary number system, employing only the digits 0 and 1, be applied in computer design. He also proposed that instructions to control the computer, as well as data, should be stored within the computer. The EDSAC (Electronic Delay Storage Automatic Calculator), built at Cambridge University in 1949, was the first computer to incorporate these ideas. It was not faster than ENIAC, but it did use the binary number system, and its instructions were stored internally. These instructions were called a program; hence the name stored-program.
1947. The SSEC (Selective Sequence Electronic Calculator) was installed at IBM New York World Headquarters in 1947 and was used through 1952. At about the same time, IBM built a machine that could multiply six-digit numbers by counting electronic pulses. This machine, which was simply a tabulating machine connected to some vacuum tubes, was known as the IBM 603 electronic multiplier.
