Before going further, it helps to understand some basic concepts about computerized records. In order to exchange information between different programs (or even between different computer systems), one needs to get the information into a format that many different programs can understand. The standard, called ASCII[1], is widely used to exchange information between different programs and operating systems. Sometimes an ASCII file is called a text file (“*.txt”) because all it contains is textual information.
ASCII files contain two types of characters: standard visible characters such as numbers and letters of the alphabet, and special characters that are called Control Characters[2]. Control Characters are used for special purposes to control the display or interpret the information in the file. If you have computerized data, you may be familiar with the <tab> and <return> control characters that are used to make text more legible.
When dealing with computerized information systems, you often hear the terms field, record, and file. A field is the smallest unit of information stored. An example of a field is a book's title. A record is a related group of fields. Many records of the same type saved together are called a file. For example, in a file of names, a record consists of the fields “First Name” and “Last Name”. A more complex file may include records with other fields such as “Phone Number” and “Address”. In other words, records contain fields filled with information, and files contain many records.
In the library world, there is a fairly well-defined method of exchanging bibliographic information between computers. This format is called MARC (for MAchine-Readable Cataloguing). Another format of the MARC is called MicroLIF (for Microcomputer Library Information Format). Alexandria has been programmed to recognize both MARC and MicroLIF files automatically during import. Alexandria can also export in both formats.
In addition to importing and exporting MARC and MicroLIF records, Alexandria is capable of importing and exporting files in a tab-delimited format. This format can be used to exchange information with other programs that utilize more complex MARC standards. Most database, spreadsheet, and word-processing programs on personal computers support files in a tab-delimited format.