Explanation:

The world's first commercial computer is that of John Napier's abacus, which he wrote about in 1617. The ivory calculating bones/rods method had been seen before in the history of the maths and calculation, but not published, and the idea employed in the elegant calculating device were very old, but Napier seems to have gotten to publish it first.
The word “rabdologia” belongs to the title of Napier's significant book (where the title is the abstract): Rabdologia, or, The art of numbring by rods : whereby the tedious operations of multiplication, and division, and of extraction of roots, both square and cubick, are avoided, being for the most part performed by addition and subtraction : with many examples for the practice of the same ...