Fig. 8.1.3 Punched cards and paper tape.Next came magnetic tape. Magnetic tape could store much more data than could ever be
stored on punched cards. And magnetic tape was not limited to the single format of a
punched card. But there were some major limitations to magnetic tape. In order to find
data on a magnetic tape file, you had to scan the entire file. And the oxide on magnetic
tape files was notoriously unstable.
Magnetic tape file represented a major step forward from punched cards. But magnetic
tape files had their own serious limitations.
Fig. 8.1.4 shows the symbol for magnetic tape files.
Fig. 8.1.4 Magnetic tape file.After magnetic tape files came disk storage. With disk storage, data could be accessed
directly. No longer was it necessary to search the entire file to find a single record.
The early forms of disk storage were expensive and slow. And there was relatively little
capacity for the early forms of disk storage. But quickly, the costs of manufacturing
Chapter 8.1: A Brief History of Data Architecture