mirror of https://github.com/BOINC/boinc.git
87 lines
3.3 KiB
HTML
87 lines
3.3 KiB
HTML
<title>Storage</title>
|
|
<body bgcolor=ffffff>
|
|
<h2>Storage</h2>
|
|
<h3>Files and data servers</h3>
|
|
<p>
|
|
The BOINC storage model is based on <b>files</b>.
|
|
The inputs and outputs of applications,
|
|
and the application executables, are files.
|
|
<p>
|
|
The BOINC core client transfers files to and from <b>data servers</b>
|
|
operated by the project, using HTTP.
|
|
<p>
|
|
A file is described by an XML element of the form
|
|
<pre>
|
|
<file_info>
|
|
<name>foobar</name>
|
|
<url>http://a.b.c/foobar</url>
|
|
<url>http://x.y.z/foobar</url>
|
|
...
|
|
<md5_cksum>123123123123</md5_cksum>
|
|
<nbytes>134423</nbytes>
|
|
<max_nbytes>200000</max_nbytes>
|
|
<status>1</status>
|
|
[ <generated_locally/> ]
|
|
[ <executable/> ]
|
|
[ <upload_when_present/> ]
|
|
[ <sticky/> ]
|
|
[ <signature_required/> ]
|
|
</file_info>
|
|
</pre>
|
|
The components are as follows:
|
|
<ul>
|
|
<li> The <b><name></b> element gives the file's name, which
|
|
must be unique within the project.
|
|
<li> Each <b><url></b> element gives a URL where the file is
|
|
(or will be) located on a data server.
|
|
<li> The <b><md5_cksum></b> element is the MD5 checksum of the file.
|
|
<li> The <b><nbytes></b> element is the size of the file in
|
|
bytes (may be greater than 2^32).
|
|
<li> The <b><max_nbytes></b> element is 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.
|
|
<li> The <b><status></b> element is 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.
|
|
<li> The <b><generated_locally></b> element, if present,
|
|
indicates that the file will be generated by an application on
|
|
the client, as opposed to being downloaded.
|
|
<li> The <b><executable></b> element, if present, indicates
|
|
that the file protections should be set to allow execution.
|
|
<li> The <b><upload_when_present></b> element, if present,
|
|
indicates that the file should be uploaded after it is created.
|
|
<li> The <b><sticky></b> element, if present, indicates that
|
|
the file should be retained on the client after its initial use.
|
|
<li> The <b><signature_required></b> element, if present,
|
|
indicates that the file should be verified with an RSA signature.
|
|
This generally only applies to executable files.
|
|
</ul>
|
|
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.
|
|
<p>
|
|
Once a file is created (on a data server or a participant host) it
|
|
is immutable.
|
|
<h3>File references</h3>
|
|
<p>
|
|
Files may be associated with <a href="work.html">workunits</a>,
|
|
<a href="result.html">results</a> and
|
|
<a href="app.html">application versions</a>.
|
|
Each such association is represented by an XML element of the form
|
|
<pre>
|
|
<file_ref>
|
|
<file_name>foobar</file_name>
|
|
[ <open_name>input</open_name> ]
|
|
[ <main_program/> ]
|
|
</file_ref>
|
|
</pre>
|
|
The components are as follows:
|
|
<ul>
|
|
<li> The <b><file_name></b> element specifies a file.
|
|
<li> The <b><open_name></b> element is the name by
|
|
which the application will refer to the file.
|
|
<li> The <b><main_program/></b> element is used for files
|
|
associated with application versions.
|
|
It indicates that this file is the application's main program.
|
|
</ul>
|