The BOINC storage model is based on files. The inputs and outputs of applications, and the application executables, are files.

The BOINC core client transfers files to and from data servers operated by the project, using HTTP.

A file is described by an XML element of the form ".html_text(" foobar http://a.b.c/foobar http://x.y.z/foobar ... 123123123123 134423 200000 1 [ ] [ ] [ ] [ ] [ ] [ ] [ ] ")." The elements are as follows: "; list_start(); list_item( "name", "The file's name, which must be unique within the project." ); list_item("url", "a URL where the file is (or will be) located on a data server." ); list_item("md5_cksum", "The MD5 checksum of the file." ); list_item("nbytes", "the size of the file in bytes (may be greater than 2^32)." ); list_item("max_nbytes", "The maximum allowable size of the file in bytes (may be greater than 2^32). This is used to prevent flooding data servers with bogus data." ); list_item("status", "0 if the file is not present, 1 if the file is present, or a negative error code if there was a problem in downloading or generating the file." ); list_item("generated_locally", "If present, indicates that the file will be generated by an application on the client, as opposed to being downloaded." ); list_item("executable", "If present, indicates that the file protections should be set to allow execution." ); list_item("upload_when_present", "If present, indicates that the file should be uploaded after it is created. "); list_item("sticky", "If present, indicates that the file should be retained on the client after its initial use." ); list_item("signature_required", "If present, indicates that the file should be verified with an RSA signature. This generally only applies to executable files." ); list_item("no_delete", "If present for an input (workunit) file, indicates that the file should NOT be removed from the download/ directory when the workunit is completed. You should use this if a particular input file or files are used by more than one workunit, or will be used by future, unqueued workunits." ); list_item("no_delete", "If present for an output (result) file, indicates that the file should NOT be removed from the upload/ directory when the corresponding workunit is completed. Use with caution - this may cause your upload/ directory to overflow." ); list_item("report_on_rpc", "Include a description of this file in scheduler RPC requests, so that the scheduler may send appropriate work using locality scheduling." ); list_end(); echo " These attributes allow the specification of various types of files: for example, input or output files that are retained for use as input to later computations.

Once a file is created (on a data server or a participant host) it is immutable.

File references

Files may be associated with workunits, results and application versions. Each such association is represented by an XML element of the form ".html_text(" foobar [ input ] [ ] ")." The elements are as follows: "; list_start(); list_item("file_name", "Specifies a file."); list_item("open_name", "The name by which the application will refer to the file."); list_item("main_program", "Used for files associated with application versions. It indicates that this file is the application's main program."); list_end(); page_tail(); ?>