Access to Digital Libraries from low speed Disconnected Environments

Digital libraries provide an important tool for expanding and improving access to knowledge, so their services must be affordable even for people in remote areas with restricted connectivity. This paper describes an architecture for accessing services and contents of digital libraries in the program EHAS (Enlace Hispano Americano de Salud) (Hispano American Health Link), which for the case of deployments in Alto Amazonas (Peru) and Cauca (Colombia), uses connectivity solutions based on VHF and HF radios, which provide intermittent (20 min max.) and low bandwidth (9600 bps max.) connections. The HTTP protocol is used to consult the contents of the library, but for downloading files the email is used through a segmentation and reassemble mechanism. In field tests conducted at 9600 bps, response times were the order of 35 s for consultation, 40 minutes for downloading a file of 100 KB and 4 hours for downloading a 1MB file.