One of my favorite moments in life was when I was

## Recursion and Basic Multiplication

## Jean Bartik and ENIAC’s Stored Software

Continue reading “Jean Bartik and ENIAC’s Stored Software”But what the women of ENIAC soon showed, and the men later came to understand, was that the programming of a computer could be just as significant as the design of its hardware.

—Walter Isaacson

## Dr. Gertrude Blanch and the Works Progress Administration (WPA) Mathematical Tables Project

## Orders of Complexity

I wish I had this table back in 1984 when I was trying to understand this stuff.

Big O Notation | Name | Example(s) |
---|---|---|

O(1) |
Constant | # Odd or Even number, # Look-up table (on average) |

O(log n) |
Logarithmic | # Finding element on sorted array with binary search |

O(n) |
Linear | # Find max element in unsorted array, # Duplicate elements in array with Hash Map |

O(n log n) |
Linearithmic | # Sorting elements in array with merge sort |

O(n^{2}) |
Quadratic | # Duplicate elements in array (naïve),# Sorting array with bubble sort |

O(n^{3}) |
Cubic | # 3 variables equation solver |

O(2^{n}) |
Exponential | # Find all subsets |

O(n!) |
Factorial | # Find all permutations of a given set/string |

and I now can firmly feel the difference between polynomial and exponential well worth this example:

n = 10 | 100 | 1000

```
```n^2 = 100 | 10000 | 1000000

`k^n = k^10 | k^100 | k^1000`

## How To Speak Machine

Phew. I just finished the final draft for HTSM, or *“How To Speak Machine,”* so it looks like it’ll get published by the end of this year.

**Pre-order Now**

## Paul Baran: Distributed Networks

Continue reading “Paul Baran: Distributed Networks”In 1962, U.S. authorities considered ways to communicate in the aftermath of a nuclear attack. How could any sort of “command and control network” survive? Paul Baran, a researcher at RAND, offered a solution: design a more robust communications network using “redundancy” and “digital” technology.

—Rand Corp

## How The Internet Works

This little sitelet at Stanford is my favorite read on this subject. It’s help me re-find my way:

Continue reading “How The Internet Works”## Wolfram’s Rule 30 and the Conus Textile

It’s the hard to beat the eery feeling of studying Wolfram’s Rule 30.

Continue reading “Wolfram’s Rule 30 and the Conus Textile”