Updated the structure, initial updates of terminology and a new page …

…about the Cray PE and Lmod.
easybuilders · klust · Mar 7, 2022 · Mar 7, 2022 · Mar 9, 2022 · Mar 10, 2022
commit 6541e8c506e49b5586be7cc0d6f4db592af0b7f7
diff --git a/docs/2022-CSC_and_LO/1_00_part1_intro.md b/docs/2022-CSC_and_LO/1_00_part1_intro.md
@@ -5,8 +5,8 @@
 *(Tue March 4th 2021, 9am-12 CET)*
 
 -   [What is EasyBuild?](1_01_what_is_easybuild.md)
-
--   [Terminology](terminology.md)
+-   [Terminology](1_02_terminology.md)
+  
 -   [Installation](installation.md) *(hands-on)*
 -   [Configuration](configuration.md) *(hands-on)*
 -   [Basic usage](basic_usage.md) *(hands-on)*
diff --git a/docs/2022-CSC_and_LO/1_01_what_is_easybuild.md b/docs/2022-CSC_and_LO/1_01_what_is_easybuild.md
@@ -15,7 +15,7 @@ and provides a **command-line interface** to facilitate the installation and man
 <img src="../../img/geek-and-poke-invaluable.png" style="float:right" width="45%"/>
 </a>
 
-### *Elevator pitch*
+## Elevator pitch
 
 EasyBuild intends to relieve HPC support teams from manually managing
 software installations while at the same time **providing a consistent and well performing
@@ -46,7 +46,7 @@ is still under development on LUMI it is not yet covered in this LUMI-specific v
 
 ---
 
-### *Key features*
+## Key features
 
 EasyBuild is capable of **fully autonomously installing (scientific) software**,
 including making sure that all necessary dependencies are installed,
@@ -73,13 +73,13 @@ packaging tools ([FPM](https://fpm.readthedocs.io)), and so on.
 
 ---
 
-### *Focus points*
+## Focus points
 
 EasyBuild was created specifically for **installing scientific software on HPC systems**,
 which is reflected in some of the design choices that were made.
 
 
-#### Performance
+### Performance
 
 EasyBuild strongly prefers to **build software from source code**, whenever possible.
 
@@ -99,7 +99,7 @@ idea to hard-code options such as ``-march=native`` or ``--xHost`` in a way that
 cannot easily overwrite those.
 
 
-#### Reproducibility
+### Reproducibility
 
 In addition to performance, **reproducibility of installations** is a core aspect of EasyBuild.
 
@@ -120,7 +120,7 @@ As we shall see when discussing the HPE Cray Programming Environment, the reprod
 in that environment due to the way the programming environment selects shared libraries at runtime.
 
 
-#### Community effort
+### Community effort
 
 In a number of different ways, we try to encourage EasyBuild users to **collaborate** and help each other out.
 
@@ -148,7 +148,7 @@ All together this leads to improved stability and consistency.
 
 ---
 
-### *What EasyBuild is* ***not***
+## What EasyBuild is ***not***
 
 EasyBuild is ***not*** **YABT (Yet Another Build Tool)**: it does *not* replace established build
 tools like CMake or ``make``, it wraps around them.
@@ -167,7 +167,7 @@ or even with the AMD compilers.
 
 ---
 
-### *Requirements*
+## Requirements
 
 Since EasyBuild is primarily intended for installing (scientific) software on HPC systems, the main target is
 systems running some flavor of **GNU/Linux**. EasyBuild also works on *macOS*,
@@ -187,7 +187,7 @@ On LUMI Lmod is used as the module tool.
 
 ---
 
-### *Development*
+## Development
 
 <a href="http://github.com/easybuilders"><img src="../../img/github_logo.png" style="float:left" width="15%"/></a>
 EasyBuild is **actively developed** by a worldwide community under the
@@ -213,7 +213,7 @@ consistent testing of incoming contributions (pull requests), and thorough regre
 
 ---
 
-### *A worldwide community*
+## A worldwide community
 
 EasyBuild has grown into a **community project** since it was first released publicy in 2012,
 and is used and developed by dozens (hundreds?) of HPC centres and consortia worldwide.
@@ -250,17 +250,17 @@ HPC sites, consortia, and companies that use EasyBuild include (but are not limi
 
 ---
 
-### *Getting help*
+## Getting help
 
-#### *Documentation*
+### *Documentation*
 
 If you have any questions about EasyBuild, make sure to check the EasyBuild documentation first,
 which is available at [**https://docs.easybuild.io**](https://docs.easybuild.io).
 
 It is not unlikely that an answer to your question is available there already.
 The [search box](https://docs.easybuild.io/en/latest/search.html) on the top left may be helpful.
 
-#### GitHub
+### GitHub
 
 <a href="http://github.com/easybuilders"><img src="../../img/github_logo.png" style="float:left" width="15%"/></a>
 
@@ -275,7 +275,7 @@ the EasyBuild maintainers can move your issue if deemed appropriate.
 Also here you can use the search box on the top left, to see if somebody else
 has already asked a similar question or reported a similar problem.
 
-#### Mailing list
+### Mailing list
 
 Feel free to ask any questions or provide feedback via the EasyBuild mailing list
 <a href="mailto:[email protected]">`[email protected]`</a>.
@@ -287,7 +287,7 @@ In 2016-2017 over 1,000 messages were posted to the EasyBuild mailing list.
 More recently this has decreased to about 700 messages per year, mostly due
 to the EasyBuild Slack channel.
 
-#### Slack
+### Slack
 
 <img src="../../img/slack_logo.png" alt="Slack logo" style="float:left" width="22%"/>
 
@@ -304,7 +304,7 @@ IRC channel (available on the [Freenode IRC network](https://freenode.net/)).
 A bot relays messages between this IRC channel and the `#general` channel in the EasyBuild Slack.
 
 
-#### Conference calls
+### Conference calls
 
 Every other week on Wednesday an EasyBuild conference call is set up to discuss recent
 developments, provide an outlook to the next EasyBuild release, and
@@ -318,4 +318,4 @@ More information, including the dates and times of the next calls, is available
 
 ---
 
-*[[next: Terminology]](terminology.md)*
+*[[next: The HPE Cray Programming Environment and Lmod]](1_02_CPE_and_Lmod.md)*
diff --git a/docs/2022-CSC_and_LO/1_02_CPE_and_Lmod.md b/docs/2022-CSC_and_LO/1_02_CPE_and_Lmod.md
@@ -0,0 +1,71 @@
+# The HPE Cray Programming Environment and Lmod
+
+*[[back: What is EasyBuild?]](1_01_what_is_easybuild.md)*
+
+---
+
+On LUMI, the main programming environment is the HPE Cray Programming Environment (further abbreviated
+as Cray PE). The environment provides several tools, including compilers, communication libraries, 
+optmized math libraries and various other libraries, analyzers and debuggers.
+
+The Cray PE is made available through *environment modules* tha allow to select particular versions of 
+tools and to configure the environment in a flexible way.
+
+---
+
+## Modules
+
+*Module* is a massively overloaded term in (scientific) software and IT in general
+(kernel modules, Python modules, and so on).
+In the context of EasyBuild, the term 'module' usually refers to an **environment module (file)**.
+
+[Environment modules](https://en.wikipedia.org/wiki/Environment_Modules_(software)) is a well established concept
+on HPC systems: it is a way to specify changes that should be made to one or more
+[environment variables](https://en.wikipedia.org/wiki/Environment_variable) in a
+[shell](https://en.wikipedia.org/wiki/Shell_(computing))-agnostic way. A module file
+is usually written in either [Tcl](https://en.wikipedia.org/wiki/Tcl) or
+[Lua](https://en.wikipedia.org/wiki/Lua_(programming_language)) syntax,
+and specifies which environment variables should be updated, and how (append,
+prepend, (re)define, undefine, etc.) upon loading the environment module.
+Unloading the environment module will restore the shell environment to its previous state.
+
+Environment module files are processed via a **modules tool**, of which there
+are several conceptually similar yet slightly different implementations.
+The oldest module tool still in use today is Environment Modules 3.2, implemented in C and 
+supporting module files written in Tcl. After a gap in developement, Xavier Delaruelle of CEA
+developed [Environment Modules 4 and 5](https://sourceforge.net/projects/modules/) which is
+fully implemented on Tcl. An alternative module tool is [Lmod](https://lmod.readthedocs.io), 
+developed by Robert McLay at TACC and implemented in LUA. This tool supports natively LUA
+module files but also offers a high degree of compatibility with Tcl-based module files
+developed for Environment Modules fia a translation layer and some API translation.
+
+The Cray PE offers a choice between the old-style Environment Modules 3.2 and Lmod, but no
+packages or official support for Environment Modules 4 or 5. On LUMI, Lmod was selected as
+the module tool. At the user level, Lmod and the various versions of Emvironment Modules
+have very simmilar commands for managing the environment, but with different options.
+The commands for searching for modules are very different though so if you are not familiar
+with Lmod and its commands for users, it is worthwile to read the 
+[LUMI documentation page on Lmod](https://docs.lumi-supercomputer.eu/computing/Lmod_modules/).
+
+---
+
+## Lmod features
+
+
+---
+
+## Cray PE components
+
+
+---
+
+## Configuring the Cray PE through modules
+
+---
+
+## Further reading
+
+
+---
+
+*[[next: Terminology]](1_03_terminology.md)*