An Ahnentafel is a list of the ancestors of a person, numbered in such a way that the starting person is number 1, the father 2, mother 3, paternal grandfather 4, paternal grandmother 5, maternal grandfather 6 and so on. The same numbering is usually used in pedigree charts, though pedigree charts are laid out differently.
BBS is an abbreviation for Bulletin Board System, and is a computer that is open to outside callers by phone or telnet, on which messages can be entered, read and replied to. There is more information on BBSs and how to use them on the BBS page.
The de Villiers/Pama numbering system is the one most commonly used by South African genealogists in published genealogies. It was developed by C. de Villiers in the 1890s, for use in his work on old Cape families. The work (and the system) was revised by Dr Cor Pama, hence the name. It is used for genealogies published in Familia, the journal of the Genealogical Society of South Africa.
In the de Villiers/Pama system, each generation is given a letter, and numbers are given to children in birth order. Thus each person in a given genealogical report has a unique identifier. The first person is a1. That person's children are b1, b2, b3 etc. The children of b1 are b1.c1, b1.c2, b1.c3 etc. Sometimes, to save space, they are written as b1c2d3.
GEDCOM is an abbreviation for GEneological Data COMmunications, and is a standard format for transmitting or transferring genealogical from one computer system or program to another.
A GEDCOM file is an Ascii text file, usually (in MS-DOS) with the extension .GED, which preserves the relationships in a genealogy data file. Most genealogy programs have the ability to import and export data as GEDCOM files. If a lineage-linked genealogy program cannot do that, it is probably not worth using.
The GEDCOM standard is being developed and refined. Some older programs will not be able to transfer all their data to or from GEDCOM files, and will not be able to import all the data from newer GEDCOM files, especially those that contain information about pictures etc.
A lineage-linked database is one in which people are linked according to their family relationships. The most fundamental relationship for genealogy is that of parents to children. In entering data in a lineage-linked database, therefore, one would also enter the links between parents and children. Through these links, other family relationships can be worked out by the computer - brothers and sisters, cousins and so on.
A Tiny Tafel is a concise list of the families that a person is researching, giving an indication of the time and place. They are described more fully in the Tiny Tafel page.