The CASIO: DC-900 Data-Cal is a vintage pocket calculator and data bank released around 1987. Part of CASIO's iconic Data-Bank series, it combined standard mathematical tools with early digital diary capabilities. Design: Pocket-sized calculator with a protective foldover flip cover. Hybrid Functionality: Stores personal data like names, phone numbers, and short text memos. Target Audience: Designed for professionals and students needing portable, paperless data access.