Common Terms and Acronyms

anal-retentive programmer

Probably the opposite of the famous "real programmer", used by Professor David L. Mills.

AM

Amplitude Modulation, information is encoded in the strength of the signal.

APM

Automatic Power Management, a feature found in modern PCs to reduce power consumption if the system is idle. APM consists of hard- and software.

DES

Data Encryption Standard, defined in Federal Information Processing Standards Publication 46 dated 1977 January 15. DES is an algorithm to encrypt a 64 bit value using a 56 bit key, giving 64 bit. Once developed and published to make secure communication possible, not allowed to be exported from USA (except in books about computer science), finally obsoleted by newer algorithms using a longer key. DES is not considered secure any more, and there were rumours about some back-door in the algorithm, but that's another story...

ESD

Electrostatic Discharge

FM

Frequency Modulation, information is encoded in the frequency of the signal.

IETF

Internet Engineering Task Force, people that try to establish acceptable standards for the Internet community.

IRIG

Inter-Range Instrumentation Group, an early attempt to synchronize time for instruments.

LAN

Local Area Network, generally a high speed Ethernet these days.

MD5

MD5 is an acronym for Message Digest #5, a strong one-way hash function designed by Ronald L. Rivest and described in [RFC 1321]. The result is 128 bits wide.

NTP

Network Time Protocol, a protocol to exchange and synchronize time on computer networks.

PPM

Part Per Million, a measure for tiny quantities, usually used instead of percent.

PPS

Pulse Per Second is a method to fine-tune frequency and offset errors using NTP.

Real Programmer

Real Programmers writing self-modifying FORTRAN code to save a clock cycle or two in a loop do no longer exists (i guess, see anal-retentive programmer).

RFC

Request For Comments, a document describing an informal Internet standard. Numbers for RFCs are assigned by the IETF (see IETF).

SA

Selective Availability, sometimes also called dither, the fact that the GPS information available to the public is made inexact by some non-obvious method. See also Section 9.1.