diff --git a/talks-public/2017-10-26-force11/2017-10-26-force11.org b/talks-public/2017-10-26-force11/2017-10-26-force11.org
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+#+COLUMNS: %40ITEM %10BEAMER_env(Env) %9BEAMER_envargs(Env Args) %10BEAMER_act(Act) %4BEAMER_col(Col) %10BEAMER_extra(Extra) %8BEAMER_opt(Opt)
+#+TITLE: Identifying 4 billion source code files
+#+SUBTITLE: Intrinsic identifiers, the Software Heritage experience
+# does not allow short title, so we override it for beamer as follows :
+#+BEAMER_HEADER: \author[Stefano Zacchiroli]{Stefano Zacchiroli}
+#+AUTHOR: Stefano Zacchiroli (Software Heritage, Inria)
+#+DATE: October 26, 2017
+#+EMAIL: zack@upsilon.cc
+
+#
+# Prelude contains all the information needed to export the main beamer latex source
+#
+
+#+INCLUDE: "../../common/modules/prelude.org" :minlevel 1
+#+INCLUDE: "../../common/modules/169.org"
+#+BEAMER_HEADER: \institute[Software Heritage]{University Paris Diderot \& Inria\\\href{mailto:zack@upsilon.cc}{\tt zack@upsilon.cc}}
+
+* Software Heritage
+  #+INCLUDE: "../../common/modules/swh-overview-sourcecode.org::#mission" :minlevel 2
+** Our principles
+#+latex: \begin{center}
+#+ATTR_LATEX: :width .7\linewidth
+file:SWH-as-foundation-slim.png
+#+latex: \end{center}
+#+BEAMER: \pause
+*** Open approach                                             :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.3
+    :BEAMER_env: block
+    :END:
+    open source, transparency
+*** Unix philosophy                         :B_block:BMCOL:noexport:noexport:
+    :PROPERTIES:
+    :BEAMER_opt:
+    :BEAMER_env: block
+    :BEAMER_col: 0.3
+    :END:
+    - do /one/ thing
+    - do it /well/
+*** In for the long haul                                      :B_block:BMCOL:
+    :PROPERTIES:
+    :BEAMER_col: 0.3
+    :BEAMER_env: block
+    :END:
+    non profit, replication
+ #+INCLUDE: "../../common/modules/status-extended.org::#archive" :minlevel 2
+* The quest for a PID
+** Our challenge in the PID arena
+*** Long term
+    Identifiers must be there for the long term
+*** No middle man
+    Identifiers must be meaningful even if resolvers go away
+*** Integrity, not just naming
+    Identifier must ensure that the retrieved object is the intended one
+*** Uniqueness by design
+    only one name for each object, each object has only one name
+** Exploring the PID landscape
+*** A lot of options out there...
+    URL, URI, PURL, URN, ARK, DOI, ...
+*** ... some are widely used
+    - articles
+    - data 
+    - even software artefacts!
+#+BEAMER: \pause
+*** We can get no satisfaction
+    \hfill of all the key criteria
+#+BEAMER: \pause
+*** 
+    \hfill we adopted something radically different \hfill
+** Intrinsic identifiers in Software Heritage
+   # R. C. Merkle, A digital signature based on a conventional encryption
+   # function, Crypto '87
+   #+BEAMER: \vspace{-3mm}
+***** Merkle tree (R. C. Merkle, Crypto 1979)                    :B_picblock:
+      :PROPERTIES:
+      :BEAMER_opt: pic=merkle, leftpic=true, width=.5\linewidth
+      :BEAMER_env: picblock
+      :BEAMER_act:
+      :END:
+      Combination of 
+       - tree
+       - hash function
+***** Classical cryptographic construction
+      fast, parallel signature of large data structures, built-in deduplication
+#+BEAMER: \pause
+      - satisfies all three criteria
+      - widely used in industry (e.g., Git, nix, blockchains, IPFS, ...)
+** Back to basics: DIOs vs. IDOs
+*** DIO (digital identifier of an object)
+    - digital identifiers for traditional (non digital) objects
+      - epistemic complications (manifestations, versions, locations, etc.)
+      - significant governance issues, ...
+#+BEAMER: \pause
+*** IDO (identifier of a digital object)
+    - (digital) identifier for digital objects
+      - much simpler to build/handle
+      - can (and must) be intrinsic
+#+BEAMER: \pause
+*** Separation of concerns
+    - yes, we \alert{need both} DIOs and IDOs
+    - no, we \alert{must not mistake} DIOs for IDOs (and viceversa)
+** Working together
+*** Example: links to /software source code/ in an article
+    Leveraging the Software Heritage universal archive:
+    - set of files :: \small\url{swh:1:rev:06741c8c37c5a384083082b99f4c5ad94cd0cd1f}\\
+      id of tree object listing all the files in a project (at a given time)
+    - revision :: \url{swh:1:rev:7598fb94d59178d65bd8d2892c19356290f5d4e3}\\
+      id of commit object which a tree and (a pointer to) the history
+    #+BEAMER: \vspace{-2mm}\pause
+    - metadata :: this /will/ involve some form of DIO
+      - and we get all the complications back
+    #+BEAMER: \vspace{-2mm}\pause
+*** Come in, we're open
+    http://www.softwareheritage.org
+    #+INCLUDE: "../../common/modules/biblio.org::#ipres2017" :only-contents t
+* A look at the internals                                        :B_appendix:
+  :PROPERTIES:
+  :BEAMER_env: appendix
+  :END:
+  #+INCLUDE: "../../common/modules/status-extended.org::#merkledemo" :minlevel 2
diff --git a/talks-public/2017-10-26-force11/Makefile b/talks-public/2017-10-26-force11/Makefile
new file mode 100644
index 0000000..68fbee7
--- /dev/null
+++ b/talks-public/2017-10-26-force11/Makefile
@@ -0,0 +1 @@
+include ../Makefile.slides