Patent US 3,949,376

Instructions are written in multi-word blocks into an instruction buffer from a slave store, and then scanned sequentially. The instruction buffer is unequally divided, a first part of a block being written into the smaller portion of the buffer during scanning of the larger portion, and the remainder of the block being written into the larger portion during scanning of the smaller portion. Thus, more time is available for an initial write from a block, which is when delays are more likely to occur due to the block having to be fetched from main store.