GridLab
Grid Application Toolkit

A simple API for Grid Applications
GAT

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Seeking on FileStreams

In addition to the ability to read and write on FileStream's GAT allows for the ability the seek on FileStream's. In other words, whenever one is reading from or writing to a FileStream one is reading from or writing to a particular place in the physical file corresponding to the FileStream. For example, one may be reading such that the next byte is the 367th byte in the physical file. Or, for example, one may be writing such that the next byte written will by the 763rd byte in the physical file. In both cases there is a ``pointer'' which indicates where the next read or write in the physical file will occur. Seeking in the act of moving this little internal pointer. (``Ok, jump ahead 23bytes, now back 267, finally go to byte 1741.'' ) So, for example, I can be reading byte 367 of a physical file using a FileStream, then decide I want to read byte 123 as the next byte. The GAT FileStream allows one to do so by seeking on the FileStream. As you might have guessed at this stage, GAT frees the application programmer from the need to worry about if the physical file corresponding to the FileStream is being accessed through TCP, UDP, http. or any other four letter acronym. One asks of GAT and low yea' shall receive.


next up previous contents
Next: LogicalFile Management Up: FileStream Management Previous: Reading and Writing on   Contents
Andre Merzky 2004-05-13