The first thing we want to do with information is _store_ it. The second thing we want to do is _combine_ it. We want equipment that makes these two processes easy and efficient. We want equipment for handling information that: 1. Costs little. 2. Holds much information in little space. 3. Is _permanent_, when we want to keep the information. 4. Is _erasable_, when we want to remove information. 5. Is _versatile_, holds easily any kind of information, and allows operations to be done easily. The amount of human effort needed to handle information correctly depends very much on the properties of the physical equipment expressing the information, although the laws of correct reasoning are independent of the equipment. For example, the great difficulty with spoken sounds as physical equipment for handling information is the trouble of storing them. The technique for doing so was mastered only about 1877 when Thomas A. Edison made the first phonograph. Even with this advance, no one can glance at a soundtrack and tell quickly what sounds are stored there; only by turning back the machine and listening to a groove can we determine this. It was not possible for the men of 2000 B.C. to wait thousands of years for the storing of spoken sounds. The problem of storing information was accordingly taken to other types of physical equipment. PHYSICAL EQUIPMENT FOR HANDLING INFORMATION PHYSICAL ARRANGED OPERATED OR LOW LITTLE PERM- ERAS- VERS- NO. OBJECTS IN OR ON PRODUCED BY COST? SPACE? ANENT? ABLE? ATILE? (1) (2) (3) (4) (5) (6) (7) (8) (9) _Mind_ 1. Nerve Human Body ✕ ✓✓ ✓ ✓ ✓✓ cells brain _Sounds_ 2. Sounds Air Voice ✓✓ ✓✓ ✕✕ ✓✓ ✓✓ 3. Sound- Wax Machines ✓ ✓ ✓✓ ✕ ✓✓ tracks cylinders, and phonograph motors records _Sights_ 4. Marks Sand Stick ✓ ✕ ✓ ✓✓ ✕ 5. Colored Cave Paintbrush ✕ ✕ ✓ ✕ ✕✕ painting walls, and paints canvases, etc. 6. Marks, Clay, Stylus, ✕✕ ✓ ✓✓ ✕✕ ✓ inscript- stone chisel ions 7. Marks Slate Chalk ✓ ✕ ✓ ✓✓ ✓ 8. Marks Paper, Pen ✓✓ ✓ ✓ ✕ ✓✓ parchment, and ink, etc. pencil 9. Letters, Paper, Printing ✓✓ ✓✓ ✓✓ ✕✕ ✓✓ etc. books, press, etc. movable type, motor, and hands