Glossary
In these pages, I've used Babbage's own terminology for components and operations in the Analytical Engine. The following table gives the equivalents in contemporary computer terminology.
| Babbage's Analytical Engine | Contemporary Computer |
|---|---|
| Accidental sign | Sign bit |
| Analyst | Programmer |
| Attendant | Operator |
| Axis | Buffer register |
| Barrel | Microcode |
| Card | Instruction |
| Card, Operation | Arithmetic instruction |
| Card, Combinatorial | Instruction, control transfer (test / jump) |
| Card, Number | Instruction, load immediate |
| Card, Variable | Instruction, load / store |
| Carriage | Carry propagation |
| Curve Drawing Apparatus | Plotter |
| Column (of Rack) | Memory (RAM) cell |
| Cycle | Loop |
| Mill | Arithmetic and Logical Unit (ALU) |
| Rack (of Columns) | Random Access Memory (RAM) |
| Run up | Overflow or Sign Bit Condition Code |
| Stepping down | Right shift |
| Stepping up | Left shift |
| Store | Memory (RAM) Array |
| Turn of the Handle | Clock cycle |