Computing History · Cluster
Early Computing
Mechanical calculation and first machines.
- 01 Finite Differences as a Mechanical Computation Method How a polynomial table is produced by addition alone, why mechanical engines avoided multiplication, and what the method costs in column count and error propagation.
- 02 Punched-Card Encoding in Hollerith Tabulating Equipment How a pinned card completes a circuit into a mercury cup, what the hole pattern encodes, and why sorting a deck became the way to answer arbitrary questions about census data.
- 03 Carry Propagation in the Difference Engine No. 2 How a figure wheel registers that a carry is owed without performing it, how the latched warnings are serviced by staggered carry arms, and what the two-phase cycle costs in timing.
- 04 The Analytical Engine Store, Mill, and Barrel Control How a planned 1830s engine separated storage from arithmetic, sequenced operations from punched cards, and used a studded barrel as a microprogram store.
- 05 Instruction Encoding on the Harvard Mark I Paper Tape How a 24-channel tape carries three eight-bit fields per instruction, what the index numbers address, and why a one-way sequence unit made program loops physical.
- 06 Relay Arithmetic and the Floating-Point Word in the Zuse Z3 How a two-register stack machine with a 22-bit floating-point word ran at a few hertz, why it had no conditional branch, and what that costs in program length.
- 07 Colossus and the Counting Attack on Lorenz Wheel Settings How a hypothesised wheel pattern is compared against ciphertext character by character, how valve counters accumulate the statistic, and why the machine was built for one search.
- 08 Ring-Counter Accumulators and the Cost of Rewiring ENIAC How ten flip-flops per digit hold a decimal number and count incoming pulses, how cables and switch banks define a program, and what function-table coding changed in 1948.
- 09 Mercury Delay-Line Memory and the Timing It Imposed How acoustic pulses recirculating in mercury hold a bit stream, why access time depends on the address, and what that forced on instruction placement and memory layout.
- 10 The Stored-Program Idea and the Disputed First Execution How one writable memory holding both numbers and orders changes machine design, and why Manchester, Cambridge, and the ENIAC teams each claimed the first run.