Math with Mathematica

I learned mathematics a different way because of programs like Mathematica. While an undergrad, after lunch I would sometimes loiter in the otherwise off limits graduate math library. One afternoon I stumbled on Moses’s ACM article on symbolic simplification followed, a few pages down, by his other article Symbolic integration: the stormy decade.…

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The instruction set of the x86 is too complicated

When reading the report of an exploit by a security firm, one invariably finds x86 assembly code. I would stumble on xbegin mayEnd cmp mutex, 0 jz weAreDone xabort $0xff and not be sure what it did. Long ago I had programmed other chips in assembly, so I felt a day or two would give me some idea of the assembly language for the Intel chips.…

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Cube roots from the square root

Last week while rummaging through some old boxes I stumbled on a notebook with a curious algorithm for computing the cube root using a pocket calculator that has a square root button. For the cube root of 8 it goes:…

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It takes days to find it

To find something anomalous one needs to be able to describe what is common. At PermissionBit we do that by recording every interaction between the CPU and the hardware (every system call). That gives us enough data to identify hacking, malware, and misuse.…

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