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Diff — Jacquard Loom

Comparing rev 2 → rev 3

	The Jacquard loom is a weaving machine invented by [[Joseph-Marie Jacquard]] of Lyon, France, first demonstrated in 1801 and patented in 1804. It wove complex figured patterns automatically by reading instructions from chains of punched cards — making it the first practical machine controlled by a stored pattern of instructions, and the ancestor of every idea of a "program" that followed.

	## How it worked

	An ordinary loom interlaces threads by lifting some warp threads and not others on each pass of the shuttle — the pattern is which threads go up. Before Jacquard, elaborate figured cloth required a human "draw boy" to select threads by hand, pass after pass, days of labor for inches of fabric.

	Jacquard's attachment replaced the draw boy with punched cards. Each card carried one row of the pattern as holes; spring-loaded needles pressed against the card, passing through where a hole was punched and lifting the corresponding hook — and thread — where there was none. Cards were chained together and fed one per pass of the shuttle. A portrait of Jacquard himself, woven on his own loom, famously required about 24,000 cards.

	Crucially:

	- The pattern was data. The same loom wove any design; you changed the deck of cards, not the machine.
	- Cards could be reused and shared. A deck was a portable library — one atelier's pattern could be run anywhere.
	- Errors were in the cards, not the machine. Punch a hole wrong and the cloth came out wrong — the world's first bugs.

	## Controversy

	The loom was not welcomed. Lyon was the center of French silk weaving, and the draw boys and journeymen whose work the cards automated attacked the early machines — looms were smashed and Jacquard was reportedly dragged from his loom and thrown into the Rhône. The technology won anyway: by 1812 there were some 11,000 Jacquard looms in France, and the riots became one of history's first recorded episodes of labor unrest against automation — decades before the Luddites made the pattern famous in England.

	## The path to programming

	The loom's cards passed the idea of instructions on paper directly into computing:

-	- Charles Babbage explicitly adopted Jacquard-style punched cards for his Analytical Engine (1830s) — its operation and variable cards were program and data, and Ada Lovelace's 1843 notes assumed that model.
+	- [[Charles Babbage]] explicitly adopted Jacquard-style punched cards for his [[Analytical Engine]] (1830s) — its operation and variable cards were program and data, and [[Ada Lovelace]]'s 1843 notes assumed that model.
	- Herman Hollerith's 1890 census tabulator used punched cards for data processing, and the company that grew from it — IBM — fixed the card as an industry standard for nearly a century.
	- Program and data punched cards remained the normal way to store a program until interactive terminals arrived in the 1970s.

	When computing historians say the Jacquard loom "invented programming," they mean it separated the machine from the sequence of operations it performs — the single idea every language since is built on.

	## See also

	- [[History of Programming]]
	- [[AdaLogic BASIC]]
	- [[Main Page]]

	[[Category:History]]
	[[Category:Hardware]]

	The Jacquard loom is a weaving machine invented by [[Joseph-Marie Jacquard]] of Lyon, France, first demonstrated in 1801 and patented in 1804. It wove complex figured patterns automatically by reading instructions from chains of punched cards — making it the first practical machine controlled by a stored pattern of instructions, and the ancestor of every idea of a "program" that followed.

	## How it worked

	An ordinary loom interlaces threads by lifting some warp threads and not others on each pass of the shuttle — the pattern is which threads go up. Before Jacquard, elaborate figured cloth required a human "draw boy" to select threads by hand, pass after pass, days of labor for inches of fabric.

	Jacquard's attachment replaced the draw boy with punched cards. Each card carried one row of the pattern as holes; spring-loaded needles pressed against the card, passing through where a hole was punched and lifting the corresponding hook — and thread — where there was none. Cards were chained together and fed one per pass of the shuttle. A portrait of Jacquard himself, woven on his own loom, famously required about 24,000 cards.

	Crucially:

	- The pattern was data. The same loom wove any design; you changed the deck of cards, not the machine.
	- Cards could be reused and shared. A deck was a portable library — one atelier's pattern could be run anywhere.
	- Errors were in the cards, not the machine. Punch a hole wrong and the cloth came out wrong — the world's first bugs.

	## Controversy

	The loom was not welcomed. Lyon was the center of French silk weaving, and the draw boys and journeymen whose work the cards automated attacked the early machines — looms were smashed and Jacquard was reportedly dragged from his loom and thrown into the Rhône. The technology won anyway: by 1812 there were some 11,000 Jacquard looms in France, and the riots became one of history's first recorded episodes of labor unrest against automation — decades before the Luddites made the pattern famous in England.

	## The path to programming

	The loom's cards passed the idea of instructions on paper directly into computing:

-	- Charles Babbage explicitly adopted Jacquard-style punched cards for his Analytical Engine (1830s) — its operation and variable cards were program and data, and Ada Lovelace's 1843 notes assumed that model.
+	- [[Charles Babbage]] explicitly adopted Jacquard-style punched cards for his [[Analytical Engine]] (1830s) — its operation and variable cards were program and data, and [[Ada Lovelace]]'s 1843 notes assumed that model.
	- Herman Hollerith's 1890 census tabulator used punched cards for data processing, and the company that grew from it — IBM — fixed the card as an industry standard for nearly a century.
	- Program and data punched cards remained the normal way to store a program until interactive terminals arrived in the 1970s.

	When computing historians say the Jacquard loom "invented programming," they mean it separated the machine from the sequence of operations it performs — the single idea every language since is built on.

	## See also

	- [[History of Programming]]
	- [[AdaLogic BASIC]]
	- [[Main Page]]

	[[Category:History]]
	[[Category:Hardware]]