IBM 729 the tape reel. A 3/4 inch gap between records allowed the mechanism enough time to stop the tape. Initial tape speed was 75 inches per second (2.95 m/s) and recording density was 200 characters per inch, giving a transfer speed of 120 kbit/s. Later 729 models supported 556 and 800 characters/inch (transfer speed 480 kbit/s). At 200 characters per inch, a single 2400 foot tape could store the equivalent of some 50,000 punched cards (about 4,000,000 six-bit bytes, or 3 MByte). The 729 series was superseded by 9 track tape drives introduced with the IBM System/360. The IBM 729 I
Nth root Any expression containing a radical, whether it is a square root, a cube root, or a higher root, is called a "radical expression", and if it contains no transcendental functions or transcendental numbers it is called an algebraic expression. In calculus, roots are treated as special cases of exponentiation, where the exponent is a fraction: Roots are particularly important in the theory of infinite series; the root test determines the radius of convergence of a power series. Roots can also be defined for complex numbers, and the complex roots of 1 (the roots of unity) play an important role in