ModDate

ModDate, short for modification date, is a timestamp associated with an item to indicate when it was last changed. The term is used across computing domains, including file systems, databases, and web resources, and is often synonymous with the last modified date or modification time.

In file systems, the modification time (mtime) records when a file’s content last changed. When the content is updated, the mtime is typically refreshed to the current time. File-system precision varies across platforms, ranging from seconds to sub-second granularity, and certain operations or editors may adjust timestamps differently. Time zone handling and clock accuracy can also affect how ModDate is interpreted or displayed.

In software development and data management, APIs expose access to ModDate. For example, programming languages provide functions to read or modify this timestamp. Common patterns include retrieving the modification time of a file, converting it to human-readable form, or updating it to a specific value. Examples include Python’s functions to get and set modification times, Java’s File and NIO APIs for last-modified times, and Node.js’s filesystem module for statistics and timestamps.

In web contexts, servers may expose a Last-Modified header that communicates the ModDate of a resource. Clients can use this information to perform conditional requests, enabling efficient caching by sending If-Modified-Since with subsequent requests.

Reliability considerations include clock synchronization, timestamp resolution, and differences among file systems or data formats. Some data formats store ModDate as a dedicated field, while others derive it from content metadata. See also Last-Modified and modification time concepts.