IBM 1360

The IBM 1360 Photo-Digital Storage System, also known as the "Terabit Memory," was a direct access storage device (DASD) introduced by IBM in 1967. It used electron beam recording technology to store data on small chips of photographic film.

The 1360 was designed to provide extremely high capacity storage at a relatively low cost per bit, although its access times were significantly slower than magnetic disk drives of the era. Each storage cell consisted of a small area on the film where data could be written or read by an electron beam. A complete system consisted of multiple storage modules, each containing hundreds of film strips.

The primary advantage of the IBM 1360 was its massive storage capacity for its time. A single system could store on the order of a terabit (10^12 bits) of data, hence the nickname "Terabit Memory." This made it suitable for applications requiring very large databases or archives.

However, the 1360 suffered from several drawbacks. Access times were relatively slow compared to other storage technologies, due to the time required to physically position the electron beam over the correct film location. The photographic film was also susceptible to wear and degradation over time, potentially leading to data loss. Due to these limitations and the advent of improved magnetic disk technology, the IBM 1360 was eventually superseded and is no longer in use.