What is digital media and computer based art?
Computer-based artworks are even more variable and ephemeral than single-channel video. Digital technologies, including software, hardware and operating systems, are rapidly evolving and prone to obsolescence; artists make computer-based works that can be mutated, replicated and re-circulated on the Web. These practices and conditions may seem to confound the very notion of collecting art. When collecting computer-based artworks, it is important to ask the most fundamental of questions. What am I collecting if the work is composed solely of computer code? What is the proper storage format for computer-based artworks? What is “metadata”? Such questions are a starting point to understanding the basics behind computer-based art.

What is "compression"?
The amount of data contained in a native video or audio file can be large enough to make playing it, using it or downloading it impossible or impractical on anything but a very fast computer with enormous storage. In order to remedy this condition, large files are compressed using algorithms, which eliminate data in a way that allows the picture/sound to be decompressed back to its original form without losing any of the original information (lossless compression). When the file needs to be made smaller, more information is removed, resulting in a file that can't fully reproduce the original picture/sound information (lossy compression). To use a compressed file it must be decompressed within the hardware or software. This procedure of compressing and decompressing data by using algorithms is called a Codec.

What does “streaming” media mean?
Streaming media refers to media (video or audio) that is viewed or heard while it is being delivered. Streaming allows a lengthy audio or video program to be transmitted over the Internet by transmitting a continuous signal in real time rather than downloading an entire clip at once. For example, most online radio is "streamed," whereas a podcast would not be considered streaming media as it is downloaded first and then consumed.

Is a DVD a proper format for collection of computer-based works?
For video DVD is an unacceptable format for long-term storage, but it is an ideal format for exhibition as it is easy to use and relatively inexpensive. For simple data storage, which requires no compression (program files, etc.) DVD is an acceptable format as long as back-up copies exist. For a more detailed discussion of storage formats and procedures, please visit the Preservation section of the Guide.

What is metadata?
Metadata is, quite simply, data about data. A common example is catalogue material for a book in a library. It gives background information and context about the book, but doesn't contain the content of the book itself. Metadata is becoming more and more important in the digital age because it allows us to locate information more easily. Keywords are a form of metadata, and many search engines rely heavily on metadata to inform their results.

What are the challenges of preserving digital media?
New media is even more dependent on constantly changing technology than single-channel works. Computer hardware, software, operating systems, and storage media all routinely fail or become obsolete.

Moreover, the longevity of digital data, or bits, remains unproven. Digital files still require a physical storage medium, which may call for even more diligent management than film reels in a vault.

For computer-based works, isn't saving the files enough?
No. Computer software and operating systems are constantly changing, often with multiple versions appearing within one year. These improvements are sometimes made with little consideration about how older media will play on new systems. How data will translate in the future is difficult to anticipate, and the look and feel of a work can vary greatly from system to system. Relevant software and operating systems must be saved along with the media files that use them, and/or the files should be migrated with very strict attention to quality control.

What does it mean to migrate or to emulate a work?
"Migration" is the most basic form of digital preservation. It simply means copying digital files to new storage media, while being careful to preserve all the qualities of the original work.

To emulate a work is to devise a way of imitating the original look of the piece by completely different means. An emulation is an upgrade of the of the original work which resembles it's same look and feel. Possible disadvantages of emulation include prohibitive expensive and inconsistency with the artist's intent.

Electronic Arts Intermix
Independent Media Arts Preservation
Variable Media Network
Netherlands Media Art Institute