Microform is a miniaturized version of a document used for non-digital archival purposes. The most common formats are microfilm reels, microfiche sheets and aperture cards (punched cards that contain a piece of microfilm).

Compared to digital storage, microforms have the following advantages and disadvantages:

• Longevity. In proprer conditions, a microfiche may last ~500 years.
• Simplicity. Microforms are simply miniaturized photographs of readable documents, so viewing them only requires optical magnification technology. The obsolescence problems of digital formats are nonexistent.
• Lossy copies. Like in many non-digital formats, some information is lost every time a copy is made, reducing the image quality.

A lot of early history of computing overlaps with that of microforms. Visionaries like ?Paul Otlet envisioned things like "a library that fits in a suitcase" storing thousands of books and a microform viewer in a small space. Also, "Memex", the influential 1945 idea from Vannevar Bush, was presented as an application of microform technology. ?Emanuel Goldberg produced the first aperture card system, i.e. a microfiche storage system with an automatic search.