Review of algorithms and flowcharts. Number systems and their representation. Codes, which detection and correction. Elementary data items. Structured data item, array, ordered list, sparse matrices, stacks, queues sequences. Trees, simple sorting and searching techniques. Concepts of records and files. Records formats and labels. Physical files, card and paper-based characteristics of these major files types, punched card, magnetic tape and direct access tiles. Logical files, definition labels, second looking and deblocking, inter–record gaps.