On the evening of 23 June 1995, the well-known painter Franz Hutting (not his real name) sent a digitized copy of his latest masterpiece Barricade from his studio in New York to his friend Percival Bartlebooth in Paris. In itself, this data transmission was not different from the millions of other, similar transmissions taking place all over the globe all the time. Ð close examination of the individual steps of this process, however, reveals how certain mathematical disciplines have become indispensable in our everyday lives and how they affect our behavior, our assumptions, and our outlook on the world around us.
Consider the following. The original painting was placed in a scanner and converted into many millions of small dots, termed pixels, that were recorded magnetically on a computer disk. Each dot was converted to a 24-bit number that specifies the color at a certain point in the painting. It was these bits that were later sent thousands of kilometers around the world, to be recorded on another magnetic disk in Paris and eventually printed. Many computer programs, mathematical algorithms, international protocols, and individual pieces of hardware were employed in the execution of this data transfer. This book examines only three crucial factors that contributed to the success of this process, as well as to those of the many other data transmissions taking place all over the globe all the time.
The first factor is time. It takes time to transfer even a single bit over any communications channel, and it takes much longer to transfer millions of bits. Time, as we all know, is money, so decreasing the number of bits being transferred saves money—always an important consideration. This factor, reducing the size of a data file, is popularly referred to as data compression, while its formal name is source coding (coding clone at the source of the data, before it is stored or transmitted).