Despite the increase in IVR technology during the 1970s, the technology was considered complex and expensive for automating tasks in call centers. The first commercial application of IVR was an order entry inventory control system designed and developed by Steven Schmidt in 1973. Early voice response systems were DSP technology based and limited to small vocabularies. In the early 1980s, Leon Ferber's Perception Technology became the first mainstream market competitor, after hard drive technology (read/write random-access to digitized voice data) had reached a cost-effective price point. At that time, a system could store digitized speech on disk, play the appropriate spoken message, and process the human's DTMF response.