Because the majority of digital information relies on two factors for curation and retrieval, it is important to separately classify how digital obsolescence impacts digital preservation through both hardware and software mediums.
Hardware Hardware concerns are two-fold in archival and library fields: in addition to the physical storage medium of magnetic tape, optical disc, or solid-state computer memory, a separate electronic device is often required for information access. And while proper storage can help mitigate some environmental vulnerabilities to storage formats (including dust, humidity, radiation, and temperature) and extend preservation for decades, there are other inevitable endangering factors. Older forms of
floating-gate MOSFET based
read-only-memory storage such as (some) cartridges and (most)
memory cards encounter their own form of bit rot when the charges representing individual bits of binary information dissipate beyond a certain level (called "flipping") and the data is rendered unreadable. The operability of a format’s appropriate playback or recording device possess their own vulnerabilities. Cassette decks and disk drives rely on the functionality of precision-manufactured moving parts that are susceptible to damages caused by repetitive physical stress and foreign materials like dust and grime. Routine maintenance, calibrations, and cleaning operations can help extend the lifetime of many devices, but broken or failing parts will need repair or replacement: sourcing parts becomes more difficult and expensive as the supply stock for older machines reaches scarcity, and user technical skills grow challenged as newer machines and storage formats use less electromechanical parts and more integrated circuits and other complex components. While in possession of indecipherable notes written by long-departed or deceased programmers, the computer hardware and
source code needed to correctly run the decoding software had been replaced and disposed of by the agency. Systemic obsolescence in software can be exemplified by the history of the
word processor WordStar. A popular option for
WYSIWYG document editing on
C/PM and
MS-DOS operating systems during the 1980s, a delayed port to
Windows 1.0 caused WordStar to lose significant market share to competitors
WordPerfect and
Microsoft Word by 1991. Further development of the Windows version stopped in 1994, and WordStar 7 for MS-DOS was last updated in 1999. Over time, any version of WordStar grew increasingly incompatible with modern versions of Windows beyond
3.1 to the frustration of long-devoted users, including authors
William F. Buckley, Jr. and
Anne Rice. Digital obsolescence has a prominent effect on the preservation of video game history, since many older games and hardware were regarded by players as ephemeral products, due to the continuous process of computer hardware upgrading and
home console generation cycles. Such cycles are often the result of both systemic and technical obsolescence. Some of the oldest computer games, like 1962's
Spacewar! for the
PDP-1 commercial
minicomputer, were developed for hardware platforms so outdated that they are virtually nonexistent today. Many older games of the 1960s and 1970s built for contemporary
mainframe terminals and
microcomputers can only be played today through
software emulation. While video games and other software applications can be orphaned by their parent developers or publishing companies, the copyright issues surrounding software are a very complicated hurdle in the path of digital preservation. == Prevention strategies ==