Editing Control store (section)

===Early use===
Early control stores were implemented as a diode-array accessed via address decoders, a form of read-only memory. This tradition dates back to the ''program timing matrix'' on the [[MIT Whirlwind]], first described in 1947. Modern [[VLSI]] processors instead use matrices of [[field-effect transistor]]s to build the [[Read-only memory|ROM]] and/or [[programmable logic array|PLA]] structures used to control the processor as well as its internal sequencer in a [[microcode]]d implementation. [[IBM System/360]] used a variety of techniques: [[CCROS]] (Card Capacitor Read-Only Storage) on the [[IBM System/360 Model 30|Model 30]], [[Transformer_read-only_storage|TROS]] (Transformer Read-Only Storage) on the [[IBM System/360 Model 40|Model 40]], and [[BCROS]] (Balanced Capacitor Read-Only Storage) on Models [[IBM System/360 Model 50|50]], [[IBM System/360 Model 65|65]] and [[IBM System/360 Model 67|67]].