my nice post

case study

2.)
A system and method for distributing software applications and data to many thousands of clients over a network. The applications are called "channels", the server is called the "transmitter", and the client is called the "tuner". The use of channels is based on subscription. The end-user needs to subscribe to channel before it can be executed. When the end-user subscribes to a channel the associated code and data is downloaded to the local hard-disk, and once downloaded the channel can be executed many times without requiring further network access. Channels can be updated automatically at regular intervals by the tuner, and as a result the end-user is no longer required to manually install software updates, instead these software and data updates are automatically downloaded and installed in the background. This method of automatic downloading of updates achieves for the client the same result as the broadcast distribution of software over a connection based network, but wherein...

receiving a first request for an update of the set of files, the request comprising an identifier of at least one selected from the set of files and the update, the identifier comprising a first number of at least one symbol;
comparing the identifier received with a set of identifiers, each identifier in the set corresponding to at least one request for an update;
responsive to the identifier received corresponding to at least one identifier in the set, retrieving a first index;
retrieving a second index;
comparing the first index retrieved with the second index retrieved to produce a result;
providing the update responsive to the result; and
responsive to the identifier received not corresponding to at least one identifier in the set, providing a request for a transmission of a second request, different from the first request received, for the update of the set of files.

5.)
A computer implemented method for down-loading mail messages in a distributed computer system. The distributed mail service system includes a plurality of client computers connected to a mail service system via a network. Mail messages are stored in message files of the mail service system, a particular mail message includes a primary component encoded in a first format, and at least one secondary component encoded in a second format different than the first component. The particular mail message is requested by a particular one of the plurality of client computer systems. The secondary component is replaced with a hot-link. The primary component and the hot-link are sent to the particular client computer.
Methods and computer program products for using a front-end server to access content stored on one or more back-end servers. The front-end server receives requests for content from client systems. Back-end servers store the content, but to the client system, it appears as if the front-end server is the content's source. Upon receiving the request, the front-end server checks the validity of the request and examines a global catalog that dynamically maps client system requests to the back-end server or servers that store the requested content. In some circumstances, the content will be stored at a single back-end server and the front-end server directs the request to that server. Alternatively, a list of back-end servers storing the requested content may be generated. If so, the front-end then uses an authentication token as a key to a hash operation that is performed on the list and a single server that is capable of satisfying the request for content is identified.

avril pic