interface.
\subsubsection pf_sto_conc Storage Main concepts
-Basically there is 3 different entities to know :
-\li the <b>storage_type</b>: here you define some kind of storage that
- you will instantiate many type on your platform. Think of it like
- a definition of throughput of a specific disk.
-\li the <b>storage</b>: instance of a <b>storage_type</b>. Defines a
- new storage of <b>storage_type</b>
-\li the <b>mount</b>: says that the storage is located into this
- specific resource.
-
-the content of a storage has to be defined in a content file that
-contains the content. The path to this file has to be passed within
-the <b>content</b> attribute . Here is a way to generate it:
+Basically there are 3 different entities available in SimGrid that
+can be used to model storages:
+
+Entity name | Description
+--------------- | -----------
+\ref pf_storage_entity_storage_type "storage_type" | Defines a template for a particular kind of storage (such as a hard-drive) and specifies important features of the storage, such as capacity, performance (read/write), content, ... Different models of hard-drives use different storage_types (because the difference between an SSD and an HDD does matter), as they differ in some specifications (e.g., different size or read/write performance).
+\ref pf_storage_entity_storage "storage" | Defines an actual instance of a storage (disk, RAM, ...); uses a ``storage_type`` template (see line above) so that you don't need to re-specify the same details over and over again.
+\ref pf_storage_entity_mount "mount" | Must be wrapped by a \ref pf_host tag; declares which storage(s) this host has mounted and where (i.e., the mountpoint).
+
+
+\anchor pf_storage_content_file
+### %Storage Content File ###
+
+In order to assess exactly how much time is spent reading from the storage,
+SimGrid needs to know what is stored in the storage device (identified by distinct (file-)name, like in a file system)
+and what size this content has.
+
+\note
+ The content file is never changed by the simulation; it is parsed once
+ per simulation and kept in memory afterwards. When the content of the
+ storage changes, only the internal SimGrid data structures change.
+
+\anchor pf_storage_content_file_structure
+#### Structure of a %Storage File ####
+
+Here is an excerpt from two storage file; if you want to see the whole file, check
+the file ``examples/platforms/content/storage_content.txt`` that comes with the
+SimGrid source code.
+
+SimGrid essentially supports two different formats: UNIX-style filepaths should
+follow the well known format:
+
+\verbatim
+/lib/libsimgrid.so.3.6.2 12710497
+/bin/smpicc 918
+/bin/smpirun 7292
+/bin/smpif2c 1990
+/bin/simgrid_update_xml 5018
+/bin/graphicator 66986
+/bin/simgrid-colorizer 2993
+/bin/smpiff 820
+/bin/tesh 356434
+\endverbatim
+
+Windows filepaths, unsurprisingly, use the windows style:
+
+\verbatim
+\Windows\avastSS.scr 41664
+\Windows\bfsvc.exe 75264
+\Windows\bootstat.dat 67584
+\Windows\CoreSingleLanguage.xml 31497
+\Windows\csup.txt 12
+\Windows\dchcfg64.exe 335464
+\Windows\dcmdev64.exe 93288
+\endverbatim
+
+\note
+ The different file formats come at a cost; in version 3.12 (and most likely
+ in later versions, too), copying files from windows-style storages to unix-style
+ storages (and vice versa) is not supported.
+
+\anchor pf_storage_content_file_create
+#### Generate a %Storage Content File ####
+
+If you want to generate a storage content file based on your own filesystem (or at least a filesystem you have access to),
+try running this command (works only on unix systems):
\verbatim
find /path/you/want -type f -exec ls -l {} \; 2>/dev/null > ./content.txt
\endverbatim
-\subsubsection pf_sto_sttp storage_type
+\subsubsection pf_storage_entities The Storage Entities
+
+These are the entities that you can use in your platform files to include
+storage in your model. See also the list of our \ref pf_storage_example_files "example files";
+these might also help you to get started.
+\anchor pf_storage_entity_storage_type
+#### \<storage_type\> ####
-<b>storage_type</b> attributes :
-\li <b>id (mandatory)</b>: the identifier of the storage_type to be
- used when referring to it.
-\li <b>model (mandatory)</b>: Unused for now by the simulator (but
- mandatory, ok)
-\li <b>content</b>: default value 0. The file containing the disk
- content. (may be moved soon or later to <b>storage</b> tag.
+Attribute name | Mandatory | Values | Description
+--------------- | --------- | ------ | -----------
+id | yes | string | Identifier of this storage_type; used when referring to it
+model | yes | string | For reasons of future backwards compatibility only; specifies the name of the model for the storage that should be used
+size | yes | string | Specifies the amount of available storage space; you can specify storage like "500GiB" or "500GB" if you want. (TODO add a link to all the available abbreviations)
+content | yes | string | Path to a \ref pf_storage_content_file "Storage Content File" on your system. This file must exist.
+content_type | no | ("txt_unix"\|"txt_win") | Determines which kind of filesystem you're using; make sure the filenames (stored in that file, see \ref pf_storage_content_file_structure "Storage Content File Structure"!)
-The tag must contains some predefined model prop, as may do some other
-resources tags.
-<b>storage_type</b> mandatory <b>model_prop</b> :
-\li <b>Bwrite</b>: value in B/s. Write throughput
-\li <b>Bread</b>: value in B/s. Read throughput
-\li <b>Bconnexion</b>: value in B/s. Connection throughput (i.e. the
- throughput of the storage connector).
+This tag must contain some predefined model properties, specified via the <model_prop> tag. Here is a list,
+see below for an example:
+
+Property id | Mandatory | Values | Description
+--------------- | --------- | ------ | -----------
+Bwrite | yes | string | Bandwidth for write access; in B/s (but you can also specify e.g. "30MBps")
+Bread | yes | string | Bandwidth for read access; in B/s (but you can also specify e.g. "30MBps")
+Bconnexion | yes | string | Throughput (of the storage connector) in B/s.
-A storage_type can also contain the <b>prop</b> tag. The prop tag allows you
-to define additional information on this storage_type following the
-attribute/value schema. You may want to use it to give information to
-the tool you use for rendering your simulation, for example.
+\note
+ A storage_type can also contain the <b><prop></b> tag. The <prop> tag allows you
+ to associate additional information to this <storage_type> and follows the
+ attribute/value schema; see the example below. You may want to use it to give information to
+ the tool you use for rendering your simulation, for example.
+Here is a complete example for the ``storage_type`` tag:
\verbatim
<storage_type id="single_HDD" model="linear_no_lat" size="4000" content_type="txt_unix">
<model_prop id="Bwrite" value="30MBps" />
<model_prop id="Bread" value="100MBps" />
<model_prop id="Bconnection" value="150MBps" />
- <b><prop id="Brand" value="Western Digital" /></b>
+ <prop id="Brand" value="Western Digital" />
</storage_type>
\endverbatim
-\subsubsection pf_sto_st storage
+\anchor pf_storage_entity_storage
+#### <storage> ####
-<b>storage_type</b> attributes :
-\li <b>id (mandatory)</b>: the identifier of the storage to be used
- when referring to it.
-\li <b>typeId (mandatory)</b>: the identifier of the storage_type that
- this storage belongs to.
-\li <b>attach (mandatory)</b>: the host (name) to which the storage is
- attached to.
+``storage`` attributes:
-\subsubsection pf_sto_mo mount
+Attribute name | Mandatory | Values | Description
+-------------- | --------- | ------ | -----------
+id | yes | string | Identifier of this ``storage``; used when referring to it
+typeId | yes | string | Here you need to refer to an already existing \ref pf_storage_entity_storage_type "\<storage_type\>"; the storage entity defined by this tag will then inherit the properties defined there.
+attach | yes | string | Name of a host (see Section \ref pf_host) that this storage is <i>physically</i> attached to (e.g., a harddrive in a computer)
+content | no | string | When specified, overwrites the content attribute of \ref pf_storage_entity_storage_type "\<storage_type\>"
+content_type | no | string | When specified, overwrites the content_type attribute of \ref pf_storage_entity_storage_type "\<storage_type\>"
-<b>mount</b> attributes :
-\li <b>id (mandatory)</b>: the id of the <b>storage</b> that must be
- mounted on that computer.
-\li <b>name (mandatory)</b>: the name that will be the logical
- reference to this disk (the mount point).
+Here are two examples:
+
+\verbatim
+ <storage id="Disk1" typeId="single_HDD" attach="bob" />
+
+ <storage id="Disk2" typeId="single_SSD"
+ content="content/win_storage_content.txt"
+ content_type="txt_windows" attach="alice" />
+\endverbatim
+
+The first example is straightforward: A disk is defined and called "Disk1"; it is
+of type "single_HDD" (shown as an example of \ref pf_storage_entity_storage_type "\<storage_type\>" above) and attached
+to a host called "bob" (the definition of this host is omitted here).
+
+The second storage is called "Disk2", is still of the same type as Disk1 but
+now specifies a new content file (so the content will be different from Disk1)
+and the filesystem uses the windows style; finally, it is attached to a second host,
+called alice (which is again not defined here).
+
+\anchor pf_storage_entity_mount
+#### <mount> ####
+
+Attributes:
+| Attribute name | Mandatory | Values | Description |
+| ---------------- | ----------- | -------- | ------------- |
+| id | yes | string | Refers to a \ref pf_storage_entity_storage "<storage>" entity that will be mounted on that computer |
+| name | yes | string | Path/location to/of the logical reference (mount point) of this disk
+
+This tag must be enclosed by a \ref pf_host tag. It then specifies where the mountpoint of a given storage device (defined by the ``id`` attribute)
+is; this location is specified by the ``name`` attribute.
+
+Here is a simple example, taken from the file ``examples/platform/storage.xml``:
+
+\verbatim
+ <storage_type id="single_SSD" model="linear_no_lat" size="500GiB">
+ <model_prop id="Bwrite" value="60MBps" />
+ <model_prop id="Bread" value="200MBps" />
+ <model_prop id="Bconnection" value="220MBps" />
+ </storage_type>
+
+ <storage id="Disk2" typeId="single_SSD"
+ content="content/win_storage_content.txt"
+ content_type="txt_windows" attach="alice" />
+ <storage id="Disk4" typeId="single_SSD"
+ content="content/small_content.txt"
+ content_type="txt_unix" attach="denise"/>
+
+ <host id="alice" power="1Gf">
+ <mount storageId="Disk2" name="c:"/>
+ </host>
+
+ <host id="denise" power="1Gf">
+ <mount storageId="Disk2" name="c:"/>
+ <mount storageId="Disk4" name="/home"/>
+ </host>
+\endverbatim
+
+This example is quite interesting, as the same device, called "Disk2", is mounted by
+two hosts at the same time! Note, however, that the host called ``alice`` is actually
+attached to this storage, as can be seen in the \ref pf_storage_entity_storage "<storage>"
+tag. This means that ``denise`` must access this storage via network, but SimGrid automatically takes
+care of that for you.
+
+Furthermore, this example shows that ``denise`` has mounted two storages with different
+filesystem types (unix and windows). In general, a host can mount as many storage devices as
+required.
+
+\note
+ Again, the difference between ``attach`` and ``mount`` is simply that
+ an attached storage is always physically inside (or connected to) that machine;
+ for instance, a USB stick is attached to one and only one machine (where it's plugged-in)
+ but it can only be mounted on others, as mounted storage can also be a remote location.
+
+\anchor pf_storage_entity_mstorage
+#### <mstorage> ####
+\note
+ This is currently unused.
-\subsubsection pf_sto_mst mstorage
-<b>Note : unused for now</b>
<b>mstorage</b> attributes :
\li <b>typeId (mandatory)</b>: the id of the <b>storage</b> that must
be mounted on that computer.
\li <b>name (mandatory)</b>: the name that will be the logical
reference to this disk (the mount point).
+\subsubsection pf_storage_example_files Example files
+
+Several examples were already discussed above; if you're interested in full examples,
+check the the following platforms:
+
+1. ``examples/platforms/storage.xml``
+2. ``examples/platforms/remote_io.xml``
+
+If you're looking for some examplary C code, you may find the source code
+available in the directory ``examples/msg/io/`` useful.
+
+\subsubsection pf_storage_examples_modelling Modelling different situations
+
+The storage functionality of SimGrid is type-agnostic, that is, the implementation
+does not presume any type of storagei, such as HDDs/SSDs, RAM,
+CD/DVD devices, USB sticks etc.
+
+This allows the user to apply the simulator for a wide variety of scenarios; one
+common scenario would be the access of remote RAM.
+
+#### Modelling the access of remote RAM ####
+
+How can this be achieved in SimGrid? Let's assume we have a setup where three hosts
+(HostA, HostB, HostC) need to access remote RAM:
+
+\verbatim
+ Host A
+ /
+RAM -- Host B
+ \
+ Host C
+\endverbatim
+
+An easy way to model this scenario is to setup and define the RAM via the
+\ref pf_storage_entity_storage "storage" and \ref pf_storage_entity_storage_type "storage type"
+entities and attach it to a remote dummy host; then, every host can have their own links
+to this host (modelling for instance certain scenarios, such as PCIe ...)
+
+\verbatim
+ Host A
+ /
+RAM - Dummy -- Host B
+ \
+ Host C
+\endverbatim
+
+Now, if read from this storage, the host that mounts this storage
+communicates to the dummy host which reads from RAM and
+sends the information back.
+
+
\section pf_routing Routing
To achieve high performance, the routing tables used within SimGrid are
