Boston University (BU) developed its own timesharing system in the 1970s for its IBM 360 and 370 mainframes. The system was based on the batch-oriented Remote Access Computing System (RACS) developed by IBM. McGill University also participated in RAX development, but their version was renamed “McGill University System for Interactive Computing” (MUSIC). Although many of the details are lost in the mists of time, both systems used some text processing tools developed at BU.
Continue reading Boston University’s RAX Library
CPU = Central Processing Unit
The CPU is the working part of the computer.
It runs your programs, makes changes to the contents of memory, and sends data to peripheral devices.
Thus, it causes the computer to produce the results you want.
The Simple CPU demonstrates how a computer works: what some very simple computer instructions look like and how they are combined to perform a calculation.
Continue reading A Simple CPU Demonstration
The one-time pad is the only encryption technique that has been mathematically proven to be uncrackable. While hard to use, it has often been the choice for highly sensitive traffic. Soviet spies used one-time pads in the 1940s and -50s. The Washington-Moscow “hot line” also uses one-time pads. However, the technique is hard to use correctly.
Photo courtesy of Cryptomuseum.com.
Whenever your browser establishes a “secure” connection to a web site, it encrypts the data. The encryption often takes place byte-by-byte, since the software can’t always predict how much data will be sent. This encryption style requires a stream cipher.
Continue reading Stream ciphers