Text editing system

Abstract

A text editing system which is completely comprised of magnetic bubble domain components (or charge-coupled devices) is described. The essential parts of the system are a passive storage comprising a plurality of shift registers which are a convertible structure, i.e., they can be randomly accessed or sequentially accessed depending upon the state of a plurality of conversion switches. This provides great flexibility in entry, retrieval, and restoring. An active storage comprising a plurality of shift registers is used for various text editing functions, such as insertion of data, deletion of data, etc. In the active storage, an editing shift register is provided which implements the various text editing functions using techniques such as freezing data bits and bypassing data bits in order to change the order of the data and to close gaps which may occur in the data. A write decoder is provided for selective entry of text into the passive storage and a read decoder is provided for selecting the contents of a specific shift register in the passive storage for data manipulation. The conversion switches are also used to control data flow paths or directions and to maintain the proper order of the data. Control circuits are provided to coordinate and control the functions of the various storages, the decoders, and the switches. The principles used for the overall system can be implemented with bubble domain devices or with charge coupled devices.