The subordinates were written as part of a suite of routines termed CCS (Computer Composition Systems). These programmes initially had paper tape input, but later operate with disc file input. Output was generally paper tape to drive a hot-metal linecaster of Monotype composing machine, and later to phototypesetting machines such as the Linotron 505 and Monophoto. Proofing output was to drum printer, with line numbers also printed to identify subsequent word editing. The subordinates are mostly concerned with the automatic hyphenation of English words. This encapsulates work done by David Martin at the University of Newcastle on both identifying hyphenation points within a word, and succinctly encoding the tables of rules and exceptions. The table at the beginning of each subordinate is thus the most important. The table is highly condensed, and uses symbols defined in the 'Extract of ICL manual on the design of the hyphenation table' (MS/2178/07).