If a user needs to run a program only infrequently, and if compiling and installing the program involves considerable overhead, the user may prefer to take advantage of a remote execution service if one is available. Netlib has experimented with making remote execution of the Fortran-to-C converter (f2c) and Fortran checking (ftnchek) programs available. We configured the Mosaic WWW browser to invoke the Tcl language interpreter to execute downloaded files of type application/x-safe-tcl. We then made downloaded user interfaces for the f2c and ftnchek programs available on a Netlib server. Users could then download the interface modules and use them to interact with the remote execution services. The user interfaces allowed the user to select files to be transferred for processing and to set various options. Our work on remote execution is experimental at this stage because a safe client execution environment for Tcl has not yet been rigorously defined, although researchers at Sun Microsystems are working on it.
Software for using ORNL's GRAIL and GENQUEST remote execution
services for doing DNA sequence analysis, gene assembly, and
sequence comparison is available through the NHSE
.
These services cannot be used from a WWW browser, but require downloading
specialized X-Windows client software. In the future, the NHSE
plans to support use of such services from a WWW browser by
means of a safe execution environment for downloadable Safe-Tcl
code, so that the client module may be executed directly from the browser.
Another possibility for remote execution is to allow users to upload executable code to a Netlib server and run it there. For example, the user might want to send an agent that would sift through and summarize computer performance data residing on Netlib. A search service such as Harvest might send an agent that would summarize the contents of Netlib and stream the summary back to an indexing engine. We are investigating the provision of this kind of user-directed remote execution using the Plan 9 operating system developed at AT& Bell Labs.