The Resource Management Package

Up until this instant the Grid, to the hapless application programmer, is nothing more than the little cloud seen so often in useless internet diagrams, for example figure .

This is at once good and bad; let me explain. The application programmer has many things to worry about: Did their kid get to school OK? Do the users really need this extra feature that will take a year to implement and only be used once? Is my stock portfolio sufficiently diversified?...Sometimes they don't want to be bothered with the details of the all the various protocols and computers that together constitute the ``grid.'' They simply want to use grid and be done with it. For these uses, this abstract picture of the grid is just the ticket.

However, there are other cases when the details actually do matter. For example, consider the case in which you need to move a large file off of one computer, as the drive is running low on space. You would need to know something about the target computer; in particular, you would need to know how much disk space it has. As another example, consider if you were trying to run a program which required a lot of CPU power on a remote computer; you couldn't run it on the local machine, it's to wimpy. You'd need to find something about the remote machine, for example the number of CPU's, the type of CPU's, the amount of memory ...In short you'd actually need to take a magnifying glass to this ``grid'' to see what's really there, for example figure .

From Chapter on we've had no need of such a magnifying glass, the cloud of the grid has served us well through these chapters. However, this blissful ignorance has its limits and can only bring us so far. Eventually we will need this magnifying glass. So, in this chapter we will learn to use the magnifying glass of GAT, the resource management package.