Sabtu, 05 Desember 2015

Distributed System

Question & Answer

1.4 A user arrives at a railway station that she has never visited before, carrying a PDA that is capable of wireless networking. Suggest how the user could be provided with information about the local services and amenities at that station, without entering the station’s name or attributes. What technical challenges must be overcome?
Answer
The user must be able to acquire the address of locally relevant information as automatically as possible. One method is for the local wireless network to provide the URL of web pages about the locality over a local wireless network. For this to work:
(1) the user must run a program on her device that listens for these URLs, and which gives the user sufficient control that she is not swamped by unwanted URLs of the places she passes through; and
(2) the means of propagating the URL (e.g. infrared or an 802.11 wireless LAN) should have a reach that
corresponds to the physical spread of the place itself.