HoS Notes
Chapter 1
ENIAC – electronic numerical integrator and computer
• Developed by Mauchly and Eckert in 1943 in the University of Pennsylvania.
• Used in war to calculate firing tables.
• The first electric, general purpose, programming computer.
• Programmed by a team of women
EDVAC – electronic discrete variable automatic computer
The ENIAC was hard to operate, switching between jobs was long and prone to errors.
• Developed by Mauchly, Eckert and Neumann
• Used delay lines
• Used devices to hold data, which loaded programs into main memory
• Working cycle: fetch next instruction, decode, and execute
3 main paradigms in the late 1940s:
1. Hardware paradigm → high speed memory
2. Van Neumann architecture paradigm → storage and arithmetic were binary
3. Modern code paradigm → flow of instructions and data mirrored the way humans used
scientific calculators
EDSAC (1949)
Full-scale computer that implemented the above 3 paradigms.
David Wheeler developed subroutines for EDSAC.
Following the development of the first electronic computers, an association was created to advance
computers, ACM – Association for Computing Machinery.
, HoS Notes
Chapter 2
IBM 701 (1952)
IBM’s first electronic computer.
• Nickname: “Defense Calculator”
• Retrieved information at once
• Used for weapon design and firing tables
• Predicted a presidential election in 1956 → Eisenhower’s reelection
IBM 704 (1954)
The IBM 704 was a successor to the 701.
• Used core memory → each cores stores 1 bit information
o Desired bit could be selected with a unique horizontal and vertical combination
o Advantages:
▪ Random access
▪ Nonvolatile
▪ Could be made small
• Supported floating-point arithmetic → used significand and exponent to position decimal point
• Three index registers
Interrupts and Channels (mid-1950s)
When the printer (today it’s our screen) would be ready, it would send an interrupt signal to the switch
control and fetch more data from the tape.
The IBM 709 introduced input and output channels in 1958.
• It could print a file, copy data from 1 tape to another, or load a file with no interruptions.
Smaller Drum-based Computers
Using magnetic drums was cheaper.
• The magnetic drums stored data on capacitors
• It was slow, but reliable and inexpensive
In 1953, Univac 1103 was built to compete against IBM 701. ERA’s success wasn’t building Univac 1103,
but the fact that it utilized drums successfully, which in turn gave rise to other cheaper computers.
In the mid-1950s improvements were made, and more portable and cheaper drums-based computers
started to appear. For example, the G-15 a drum-based computer built in 1953.
• It was hard to program, but very fast
, HoS Notes
Scientific Programming Tools
The first programs were called “Compilers” and were originally written by the Univac software team.
First high-level language associated with a compiler was the Fortran. It was created by an IBM engineer
in 1954 and was introduced to the IBM 704 in 1957. It was successful due how easy it was to use:
• Simple syntax, like Algebra
• Engineers liked the similarity
• It was fast and efficient
SHARE and the Operating System
SHARE was an IBM group that shared their experiences using the computers
• They developed library of routines, bug reporting standards, and it created code and document
distributions
SHARE tried to standardize working methods, and they helped shape Operating System software
The point of an Operating System was that the application code could control the hardware directly,
eliminating the need for manual labor (mostly).
The first program to be in the memory was “Monitors”:
• Keeps tabs on the progress of a program to provide debugging information.
• And it triggered code to load other code
In 1956, SOS was launched by SHARE.
• Automated much of the work,
• Provided batch control,
• Output buffering,
• Ad macro instructions for input and output subroutines
Mathematical Software
Error reports were needed for teaching purposes.
University of Waterloo developed a Fortran compiler called Watfor. Watfor gave goof error diagnostics.
In the 1960s there was a big effort to develop a reliable and efficient implementations of modern math
methods and package them as software.
One of the first projects was “Eispack” (1973), which calculated matrix eigenvalues.
However, there was an issue with Fortran. Computers used different standards and so one could
compile the same code on 2 different machines and get a different result.
Chapter 1
ENIAC – electronic numerical integrator and computer
• Developed by Mauchly and Eckert in 1943 in the University of Pennsylvania.
• Used in war to calculate firing tables.
• The first electric, general purpose, programming computer.
• Programmed by a team of women
EDVAC – electronic discrete variable automatic computer
The ENIAC was hard to operate, switching between jobs was long and prone to errors.
• Developed by Mauchly, Eckert and Neumann
• Used delay lines
• Used devices to hold data, which loaded programs into main memory
• Working cycle: fetch next instruction, decode, and execute
3 main paradigms in the late 1940s:
1. Hardware paradigm → high speed memory
2. Van Neumann architecture paradigm → storage and arithmetic were binary
3. Modern code paradigm → flow of instructions and data mirrored the way humans used
scientific calculators
EDSAC (1949)
Full-scale computer that implemented the above 3 paradigms.
David Wheeler developed subroutines for EDSAC.
Following the development of the first electronic computers, an association was created to advance
computers, ACM – Association for Computing Machinery.
, HoS Notes
Chapter 2
IBM 701 (1952)
IBM’s first electronic computer.
• Nickname: “Defense Calculator”
• Retrieved information at once
• Used for weapon design and firing tables
• Predicted a presidential election in 1956 → Eisenhower’s reelection
IBM 704 (1954)
The IBM 704 was a successor to the 701.
• Used core memory → each cores stores 1 bit information
o Desired bit could be selected with a unique horizontal and vertical combination
o Advantages:
▪ Random access
▪ Nonvolatile
▪ Could be made small
• Supported floating-point arithmetic → used significand and exponent to position decimal point
• Three index registers
Interrupts and Channels (mid-1950s)
When the printer (today it’s our screen) would be ready, it would send an interrupt signal to the switch
control and fetch more data from the tape.
The IBM 709 introduced input and output channels in 1958.
• It could print a file, copy data from 1 tape to another, or load a file with no interruptions.
Smaller Drum-based Computers
Using magnetic drums was cheaper.
• The magnetic drums stored data on capacitors
• It was slow, but reliable and inexpensive
In 1953, Univac 1103 was built to compete against IBM 701. ERA’s success wasn’t building Univac 1103,
but the fact that it utilized drums successfully, which in turn gave rise to other cheaper computers.
In the mid-1950s improvements were made, and more portable and cheaper drums-based computers
started to appear. For example, the G-15 a drum-based computer built in 1953.
• It was hard to program, but very fast
, HoS Notes
Scientific Programming Tools
The first programs were called “Compilers” and were originally written by the Univac software team.
First high-level language associated with a compiler was the Fortran. It was created by an IBM engineer
in 1954 and was introduced to the IBM 704 in 1957. It was successful due how easy it was to use:
• Simple syntax, like Algebra
• Engineers liked the similarity
• It was fast and efficient
SHARE and the Operating System
SHARE was an IBM group that shared their experiences using the computers
• They developed library of routines, bug reporting standards, and it created code and document
distributions
SHARE tried to standardize working methods, and they helped shape Operating System software
The point of an Operating System was that the application code could control the hardware directly,
eliminating the need for manual labor (mostly).
The first program to be in the memory was “Monitors”:
• Keeps tabs on the progress of a program to provide debugging information.
• And it triggered code to load other code
In 1956, SOS was launched by SHARE.
• Automated much of the work,
• Provided batch control,
• Output buffering,
• Ad macro instructions for input and output subroutines
Mathematical Software
Error reports were needed for teaching purposes.
University of Waterloo developed a Fortran compiler called Watfor. Watfor gave goof error diagnostics.
In the 1960s there was a big effort to develop a reliable and efficient implementations of modern math
methods and package them as software.
One of the first projects was “Eispack” (1973), which calculated matrix eigenvalues.
However, there was an issue with Fortran. Computers used different standards and so one could
compile the same code on 2 different machines and get a different result.
