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Small Adders Part 2

1 Small Adders Part 2

Bob Otnes

Teil 2 des Vortrags, gehalten beim 2. Greifswalder Symposium zur Entwicklung der Rechentechnik 12. - 14. September 2003, erschienen in Girbardt/Schmidt 9-2003
Im Rechnerlexikon mit freundlicher Genehmigung des Verfassers.

2 Small Adder Classification System - Taxonomy

I have spent some time in attempting to create a taxonomy for small adders. I am currently restricting myself to this subset of calculation mainly from a lack of the kind of knowledge necessary to handle the myriad of three- and four-function machines. Is a taxonomy necessary? I think that the answer is yes. The reason is that there are many machines that appear to be similar that have very different internal mechanisms. These differences tend to show up in the method of carrying from one digit to another, but are not limited to this.

0. Abaci: Are of two forms: tables with lines upon which the position of counters indicates a numerical value, or frames with beads sliding on rods.

0.1 - Counting Tables using Jetons, Counters, etc.

0.2 - Sampam, Saroban and Shotky

1. Column Adders:
Add one column at a time, putting the least significant sum digit at the bottom and the carry at the top of the left column. While column adders can have two or more result digits, you can only add into the rightmost digit, and then generally only with the integers one through nine. There are exceptions to this: the Centigraph only has five keys, and the Sebastian seems to change in units of five.

1.1 - Dial:

1.2 - Chain:

1.3 - Key - Generally Nine Key

1.4 - Band

1.5 - Spiral and Helix

1.6 - Push Down "Pencil"

2. Row Adders:
Add row by row, one row at a time. Must be able to add two or more columns at a time. There is a potential overlap here. For example, a row adder can be used as a column adder, so that all row adders are also column adders. Capacity is the consideration. The Addachine and Hart are somewhat close in design; however, the larger Hart can add two columns at a time, compared to only one for the Addachine.

2.1 - Dial
Usually have three or more dials and corresponding result digits; numbers can be added into any one of the dials

2.1.1 - Dials in a Row - Manual Carry and No Clearing Mechanism - Assisted Manual Carry and No Clearing Mechanism - Hardware Carry Using Gears - No Clearing Mechanism, No Subtraction - No Clearing Mechanism, With Subtraction - With Clearing Mechanism and No Subtraction - With Clearing Mechanism and Subtraction - Hardware Carry Using Springs - No Clearing Mechanism - With Clearing Mechanism

2.1.2 - Concentric Dials - Full Hardware Carry

2.2 - Line

2.2.1 - Rectilinear Lines (both Horizontal and Vertical); Manual Carry

2.2.2 - Vertical Lines - Slides - Kummer - Plain - Kummer - Double Register Subtraction - Kummer - With Clearing - Kummer - Shifting Plate Subtraction with Clearing - Kummer - Double Panel Subtraction with Clearing - Kummer - Hardware Complementary Subtraction

2.2.3 - Chain Input - Full Hardware Carry and Clearing Mechanism

2.2.4 - Bands and Ribbons

2.2.5 - Racks

2.3 - Miscellaneous

2.1 Copyright

Alle Rechte beim Verfasser

Hinweis: Copyright 2003 Robert K. Otnes
Please do not copy or reprint

Dieses Material ist Bestandteil eines Buches von Bob Otnes, das voraussichtlich noch im Jahre 2004 erscheinen wird.

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