- Soon after its publication Kepler’s “Epitome” was placed along with the book of Copernicus, on the list of books prohibited by the Congregation of the Index at Rome, and he feared that this might prevent the publication or sale of his books in Austria also, but was told that though Galileo’s violence was getting him into trouble, there would be no difficulty in obtaining permission for learned men to read any prohibited books, and that he (Kepler) need fear nothing so long as he remained quiet. [Chapter 6]
- Two interesting XOR circuits inside the Intel 386 processor (righto.com)
Intel’s 386 processor (1985) was an important advance in the x86 architecture, not only moving to a 32-bit processor but also switching to a CMOS implementation. I’ve been reverse-engineering parts of the 386 chip and came across two interesting and completely different circuits that the 386 uses to implement an XOR gate: one uses standard-cell logic while the other uses pass-transistor logic. In this article, I take a look at those circuits.