Before revision: Software took advantage of this flexibility: system software such as linker symbol tables used the limited character set of 6-bit bytes for efficiency; most software used 7-bit ASCII, packed 5 to a word with one unused bit; and the C implementation used 9-bit bytes because C requires all memory to be byte-addressable.
After revision: Programs took advantage of this flexibility: those not needing lowercase letters used the limited character set of 6-bit bytes for efficiency; most used 7-bit ASCII, packed 5 to a word with one unused bit; and the C implementation used 9-bit bytes because C requires all memory to be byte-addressable.