Download Delay, Tolerable Wait Time, and Online Learning

Download delay, also known as “download time” and “tolerable wait time (TWT),” is the amount of time needed for instructional materials to appear on a Web page on a client computer after the page is accessed from a server. It is a new challenge specific to designing and using Internet-based materials (Davis & Hantula, 2001), but is related to an older mainframe computing difficulty known as system response time (SRT), the time between when a user issues a command and the system responds to the command. Download delay/TWT is primarily a function of the size of the data files being transmitted from the server to the client, the technological limitations of the client and server computers as well as the network infrastructure. A file of equal size may download more slowly or quickly on different client computers, depending on capabilities of the hardware, speed of the network and connections, and relative efficiency in the design of programs and transfer protocols. In an Internet environment with a broadband connection, download delay is usually a matter of seconds, often fractions of a second.