1
Unit 01
Introduction to
Computer
Technology
, 2
1.1
HISTORY OF COMPUTERS
1. The Historical "Discovery" at Harvard
• The Meeting (1936): Howard Aiken proposed a giant calculating machine to Harvard.
He was directed to a lab technician (Carmelo Lanza), who showed him a "similar
contraption" in the attic.
• The Artifact: Aiken found brass wheels he believed to be from Babbage’s Analytical
Engine.
• The Correction: Historical analysis suggests these wheels were actually from a
demonstration piece of the Difference Engine I, one of six created by Babbage’s son,
Henry, after his father’s death.
• Aiken’s Inspiration: Despite the technical inaccuracy, finding the wheels validated
Aiken’s vision. He credited Babbage’s books and the artifact as his "whole education in
computers."
2. Technical Connections: Babbage vs. Aiken
• Convergent Evolution: There is a striking physical resemblance between Babbage’s
Difference Engine II and Aiken’s Harvard Mark I (ASCC). Both featured:
o A long, tall frame.
o A drive shaft running along the bottom.
o Printers located at one end.
• The Difference: While Babbage was limited by 19th-century funding and material
science, Aiken had the industrial backing of IBM and more advanced manufacturing
tools.
3. The Legacy of the "Analytical Engine"
• Complexity: The Analytical Engine was Babbage's more ambitious design (a general-
purpose computer), while the Difference Engine was designed for specific
mathematical tables.
• Information Source: Aiken likely never saw the full plans for the Analytical Engine (as
they were in London), but he had access to published accounts and high-level
descriptions.
4. Key Figures and Influence
• Howard Aiken: Viewed himself as the "inheritor" of Babbage’s quest.
• Grace Hopper: * A lieutenant under Aiken and general editor of the ASCC manual.
o Developed the first compiler and major programming languages.
o The team held Babbage in high regard, treating his reputation as a "charge" to
be kept.
• Babbage’s Prophecy: Babbage famously wrote that he would leave his reputation to
whoever succeeded in building a mathematical engine, as only they could truly
appreciate his efforts.
5. Critical Perspectives & The Moore School
• Technological Shift: By 1946, the focus shifted from Aiken’s
mechanical/electromechanical approach to electronic stored-program computers
(like ENIAC).
, 3
Source Code as History
1. The "Source Code as History" Problem
• The Historian’s Barrier: Most history is written from documentation (letters, manuals,
reports) rather than the source code itself.
• Language Obsolescence: Future historians may lack the skill or desire to learn "dead"
programming languages, leading to a shallow understanding of how early pioneers
actually solved problems.
• The Turing Mystery: An example is Alan Turing’s handwritten note, "How did this
happen?", on a program bug. Without understanding Autocode (the language he
used), we cannot know if the bug was a simple typo or a deep conceptual error that
changed his understanding of logic.
2. The First Stored
Program (June 21, 1948)
• The Milestone: The first
stored program was
written by Tom Kilburn
and run on the
Manchester "Baby."
• The Function: It was a
mathematical program
designed to find the
highest factor of a
number.
• Performance: First
run: 1 minute.
Second run (larger number): 2
minutes and 52 seconds.
• Historical Gap:
Surprisingly, the original
program was never
documented. Kilburn
allegedly never wrote
another program, and the
version historians study
today is an amended
version written by
Geoffrey C. Tootill a
month later.
Page from Alan Turing's notebook showing an annotated program with a bug
Unit 01
Introduction to
Computer
Technology
, 2
1.1
HISTORY OF COMPUTERS
1. The Historical "Discovery" at Harvard
• The Meeting (1936): Howard Aiken proposed a giant calculating machine to Harvard.
He was directed to a lab technician (Carmelo Lanza), who showed him a "similar
contraption" in the attic.
• The Artifact: Aiken found brass wheels he believed to be from Babbage’s Analytical
Engine.
• The Correction: Historical analysis suggests these wheels were actually from a
demonstration piece of the Difference Engine I, one of six created by Babbage’s son,
Henry, after his father’s death.
• Aiken’s Inspiration: Despite the technical inaccuracy, finding the wheels validated
Aiken’s vision. He credited Babbage’s books and the artifact as his "whole education in
computers."
2. Technical Connections: Babbage vs. Aiken
• Convergent Evolution: There is a striking physical resemblance between Babbage’s
Difference Engine II and Aiken’s Harvard Mark I (ASCC). Both featured:
o A long, tall frame.
o A drive shaft running along the bottom.
o Printers located at one end.
• The Difference: While Babbage was limited by 19th-century funding and material
science, Aiken had the industrial backing of IBM and more advanced manufacturing
tools.
3. The Legacy of the "Analytical Engine"
• Complexity: The Analytical Engine was Babbage's more ambitious design (a general-
purpose computer), while the Difference Engine was designed for specific
mathematical tables.
• Information Source: Aiken likely never saw the full plans for the Analytical Engine (as
they were in London), but he had access to published accounts and high-level
descriptions.
4. Key Figures and Influence
• Howard Aiken: Viewed himself as the "inheritor" of Babbage’s quest.
• Grace Hopper: * A lieutenant under Aiken and general editor of the ASCC manual.
o Developed the first compiler and major programming languages.
o The team held Babbage in high regard, treating his reputation as a "charge" to
be kept.
• Babbage’s Prophecy: Babbage famously wrote that he would leave his reputation to
whoever succeeded in building a mathematical engine, as only they could truly
appreciate his efforts.
5. Critical Perspectives & The Moore School
• Technological Shift: By 1946, the focus shifted from Aiken’s
mechanical/electromechanical approach to electronic stored-program computers
(like ENIAC).
, 3
Source Code as History
1. The "Source Code as History" Problem
• The Historian’s Barrier: Most history is written from documentation (letters, manuals,
reports) rather than the source code itself.
• Language Obsolescence: Future historians may lack the skill or desire to learn "dead"
programming languages, leading to a shallow understanding of how early pioneers
actually solved problems.
• The Turing Mystery: An example is Alan Turing’s handwritten note, "How did this
happen?", on a program bug. Without understanding Autocode (the language he
used), we cannot know if the bug was a simple typo or a deep conceptual error that
changed his understanding of logic.
2. The First Stored
Program (June 21, 1948)
• The Milestone: The first
stored program was
written by Tom Kilburn
and run on the
Manchester "Baby."
• The Function: It was a
mathematical program
designed to find the
highest factor of a
number.
• Performance: First
run: 1 minute.
Second run (larger number): 2
minutes and 52 seconds.
• Historical Gap:
Surprisingly, the original
program was never
documented. Kilburn
allegedly never wrote
another program, and the
version historians study
today is an amended
version written by
Geoffrey C. Tootill a
month later.
Page from Alan Turing's notebook showing an annotated program with a bug
