What is the difference between migration and emulation for keeping old electronic records readable?

Electronic records can become unreadable long before they reach the end of their retention period. The file format may be obsolete, the software that created it may no longer run, or the hardware may no longer exist. Migration and emulation are the two main strategies for keeping digital records usable over time. They solve the same problem in opposite ways.

Migration

Migration changes the record so it works in today’s environment. The content is converted from an obsolete or at-risk format into a current, well-supported one, and the process is repeated periodically as technology keeps moving.

Common examples include converting an old word-processing file to PDF/A, or moving a database into a modern, documented format.

• Strength: the record opens with ordinary current software; no special tools are needed by the end user.
• Risk: each conversion can lose formatting, structure, or embedded features, and small losses can accumulate across repeated migrations.

Because migration alters the object, it is important to document each conversion and verify that the meaning, content, and essential characteristics survive.

Emulation

Emulation leaves the original record untouched and instead recreates the old computing environment. Emulation software imitates the original operating system or hardware so the original software and file can run as they did when first created.

• Strength: preserves the authentic look, behavior, and structure of the original, which matters for complex or interactive records.
• Risk: it is more technically demanding, requires maintaining old software, and may raise licensing questions.

Choosing an approach

Neither approach is universally “better.” The right choice depends on the record’s value, its complexity, and how it will be used.

• Use migration for high-volume, document-style records where readability and easy access matter most.
• Use emulation for records whose original behavior or appearance is essential and hard to reproduce.

Many organizations use both, and pair either strategy with sound practices: open and documented formats, fixity checks to confirm files have not changed, good metadata, and multiple copies. Whatever method you pick, the goal is the same — keeping the record readable, authentic, and trustworthy for as long as it must be retained.

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