 Bush writes that a machine with the "speed and flexibility" of the brain is not attainable, but improvements could be made in regard to the capacity to obtain informational "permanence and clarity".Bush also relates that, unlike digital technology, Memex would be of no significant aid to business or profitable ventures, and as a consequence its development would occur only long after the mechanization of libraries and the introduction of what he describes as the specialized "group machine", which would be useful for the sharing of ideas in fields such as medicine.Furthermore, although Bush discusses the compressional ability and rapidity so key to modern machines, he relates that speed will not be an integral part of Memex, stating that a tenth of a second would be an acceptable interval for its data retrieval, rather than the billionths of a second that modern computers are capable of.