Even in today's technological environment, the classroom remains an integral part of every military training programme, with an instructor standing on a dias addressing a class of students. ;These instructors are supported by traditional teaching aids such as blackboard and chalk, and are likely to be able to call on more modern - albeit relatively unsophisticated - training aids such as overhead projectors (OHP) and video projectors. ;Some more advanced electronic technology began to penetrate the classroom environment from the 1970s onwards. ;For example, specialist, computer-based, interactive devices were introduced to teach manual skills such as typing. ;Later 'programmed learning' appeared, finding applications in areas such as language laboratories.