  Do physical laws limit rate of any serial data processor? A positive answer
suggested by H. J. Bremermann in 1962 has to be corrected to make it compatible
with general relativity. As a result, Bremermann's limit, proportional to mass
M of system, Mc^2/h = ~ (M/gram) 10^47 bits per second, should be replaced by
an absolute limit (c^5/Gh)^1/2= ~ 10^43 bits per second, where universal
constants c, G, and h are the speed of light, the gravitational constant, and
Planck's constant.
