From 842948b8d2309c600786b8bf6147b460862512ff Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Wed, 27 Dec 2017 14:43:53 +0100 Subject: update, final version before presentation --- .../bbs_early_internet.adoc | 155 ++++++-- .../bbs_early_internet-34c3/bbs_early_internet.css | 31 ++ .../bbs_early_internet.html | 423 +++++++++++++++++++-- .../bbs_early_internet__1.png | Bin 0 -> 64540 bytes 2017/bbs_early_internet-34c3/images/analogm.png | Bin 0 -> 86405 bytes 2017/bbs_early_internet-34c3/images/mosaic.jpg | Bin 0 -> 58972 bytes 2017/bbs_early_internet-34c3/images/pict4_Lg.jpg | Bin 0 -> 206067 bytes .../images/pots_fig10.2.png | Bin 0 -> 109186 bytes 8 files changed, 553 insertions(+), 56 deletions(-) create mode 100644 2017/bbs_early_internet-34c3/bbs_early_internet.css create mode 100644 2017/bbs_early_internet-34c3/bbs_early_internet__1.png create mode 100644 2017/bbs_early_internet-34c3/images/analogm.png create mode 100644 2017/bbs_early_internet-34c3/images/mosaic.jpg create mode 100644 2017/bbs_early_internet-34c3/images/pict4_Lg.jpg create mode 100644 2017/bbs_early_internet-34c3/images/pots_fig10.2.png (limited to '2017') diff --git a/2017/bbs_early_internet-34c3/bbs_early_internet.adoc b/2017/bbs_early_internet-34c3/bbs_early_internet.adoc index 9a027eb..a7463ee 100644 --- a/2017/bbs_early_internet-34c3/bbs_early_internet.adoc +++ b/2017/bbs_early_internet-34c3/bbs_early_internet.adoc @@ -5,6 +5,19 @@ BBSs and Early Internet Access in Germany :backend: slidy :max-width: 45em +== Introduction + +[role="incremental"] +* this is not a high-tech talk +* way fewer acronyms than in mots of my other talks +* I didn't invent any of the technologies covered +* I didn't write any of the software covered +* Just a mere user and operator/sysadming +* .. this is the world I grew up in (age 11 onwards) + +[role="incremental"] +* very limited information available in literature and on the WWW +* lots of younger members of our community lack this history == Circuit Switched Telephony @@ -17,10 +30,21 @@ BBSs and Early Internet Access in Germany == Hardware * Telephone -* Copper wire -* Telephone Exchange +* Copper wire[s] +* Telephone Exchange[s] + +image:images/pots_fig10.2.png[width="80%"] + +== Phone Charges -== Accoustic Coupler +In Germany during the 80ies and 90ies + +* even local calls were metered / charged +* flat rates didn't exist +* various zones between local and long distance +* not many people could afford long distance BBSing + +== Acoustic Coupler * First devices to transmit bits as audible tones over telephone * User manually dialled phone number like voice call @@ -30,12 +54,16 @@ image:images/accoustic_coupler.jpg[width="50%"] == Modems -Automatization of the accoustic coupler +Automation of the acoustic coupler -* Avoid speaker/micrphone path +* Avoid _air gap_ speaker/microphone path * directly generate/receive tones on phone line * directly dial the phone number / answer the line +image:images/analogm.png[width="80%"] + +== Modems + image:images/Modems.jpg[width="50%",float="right"] == Modem Speeds / Standards @@ -62,6 +90,18 @@ What's a BBS? * Computer with Modem accepting incoming calls * offering interactive service to users who dial in +To operate a BBS, you had to have + +* a separate/dedicated computer +** most BBS software predated/predates multi-tasking OSs +* running 24/7 +* attached to separate / dedicated phone line + +To use a BBS, you + +* power your computer when using it +* can share your regular phone line with the modem + == Content * bulletin boards / message boards @@ -75,14 +115,20 @@ image:images/dosbox-telemate-login.png[width="50%"] == Technology/Software * Both sides: Computer + Modem -* BBS Side +* BBS Side Software ** BBS Software -** often extended by "doors" (external programs, think of CGI for web) -* User Side +** often extended by "doors" (external programs, think of CGI in Web) +* User Side Software ** Terminal Program (e.g. TELIX, Telemate for DOS) image:images/telemate.jpg[width="50%"] +== Demo + +Time for a demo + +NOTE: I'm using telnet instead of modem/dialup (POTS lines hard to find these days) + == The "BBS Protocol Stack" @@ -125,6 +171,8 @@ image:images/xpmenu.gif[width="60%"] == BBS networks (store + forward) +As opposed to individual BBSs with isolated communities... + Idea: Replicate bulletin / message boards between independent BBSs, for * scalability in number of users @@ -146,10 +194,10 @@ Idea: Replicate bulletin / message boards between independent BBSs, for == Example: FIDOnet * Starts in 1984 with two BBSs -* Initial limit of 250 nodes reached in 1985 -* Hierarchic, Regoinal routing/Adressing introduced in 1986 -** Nodelist defines all nodes of the network + hierarchy -* Addresses like "Harald Welte @ 2:2490/1343" +* Initial technological limit of 250 nodes reached in 1985 +* Hierarchic, Regional routing/Addressing introduced in 1986 +** _Nodelist_ defines all nodes of the network + hierarchy +* Addresses like *Harald Welte @ 2:2490/1343* * Up to 39,000 nodes in 1996, estimated 2 Million users world-wide == Example: Z-Netz @@ -158,22 +206,25 @@ Idea: Replicate bulletin / message boards between independent BBSs, for * Later renamed to Z-Netz as the ZConnect protocol was implemented in other software ** Standards defined based on perceived complexity of RFCs and Usenet/UUCP * CrossPoint (DOS) most popular point software for ZConnect -* Addresses like H.WELTE@SILVER, later H.WELTE@SILVER.zer +* Addresses like *H.WELTE@SILVER*, later *H.WELTE@SILVER.zer* == Example: UseNet * Established in 1980 in the US -* Uses UUCP (Unix-to-Unix-Copy) as transport mechanism over Modmes -** UUCP was created in the 1970ies and used to copy files, including Internet Mal +* Uses UUCP (Unix-to-Unix-Copy) as transport mechanism over Modems +** UUCP was created in the 1970ies and used to copy files, including Internet Mail * Usenet News format (RFC850) designed very similar to Internet Mail (RFC822) -* Hierarchy of News Groups that gets replicated / flooded accross the network +* Hierarchy of News Groups that gets replicated / flooded across the network, e.g. +** comp.* — Discussion of computer-related topics like ``comp.lang.c++'' +** sci.* — Discussion of scientific subjects * Routing defined in route maps == Curiosity: Floppy Poll/Point +[role="incremental"] * Not everyone had a phone line in the 1990ies ** particularly Eastern Germany had big lack of phone lines -* Some people thus exchanged daily floppies in evenlopes and mailed them as postal letters +* Some people thus exchanged daily floppies in envelopes and mailed them as postal letters * Messages arrived about one day later, but with 1-2 days latency even inside the dial-up store-and-forward network, it hardly matters image:images/floppy-disk-1219954_640.png[width="30%"] @@ -196,7 +247,24 @@ Early ways to access Internet: * if you had dial-up access to a Unix box * you could run SLIP on both sides, transporting IP over the modem line -** IP. At home. In your apartment !!1! +** Result: IP. At home. In your apartment !!1! +* later superseded by PPP (auto-configuration, authentication, compression, ...) + +Popular software stack looked like: + +* Windows 3.11 + Trumpet Winsock (Windows didn't have TCP/IP!) +* NCSA Mosaic as web-1.0 browser (1993 onwards) + +image:images/mosaic.jpg[] + +== Internet on PCs before Linux + +* if you didn't have a 386 or if Linux didn't exist yet +* there was KA9Q NOS +** Implementation of TCP/IP, SLIP, PPP for CP/M and DOS +** POP3 + SMTP server + client, IP routing, telnet, ARP, etc. +* you could run SLIP on both sides, transporting IP over the modem line +** Result: IP. At home. In your apartment !!1! * later superseded by PPP (auto-configuration, authentication, compression, ...) @@ -225,7 +293,7 @@ image:images/isdn.jpg[width="50%"] * Hard to access in early/mid 1990ies outside of academia * Almost no commercial ISPs (XLink, EUnet) - and very expensive * Grass-Roots groups of enthusiasts established themselves -* Kommunikationsnetz Franken e.V. (KNF, franken.de) one of them +* Kommunikationsnetz Franken e.V. (KNF, ``franken.de'') one of them ** dial-up UUCP and shortly later IP for personal, non-commercial users ** POPs in Nürnberg, Fürth, Erlangen, Forchheim, Würzburg, Regensburg, ... ** Every user got 6 static IP addresses routed to wherever he dialed in (OSPF!) @@ -240,7 +308,7 @@ image:images/isdn.jpg[width="50%"] ** IN members served more than 300,000 users at one point ** Dissolved in 2000, when *** commercial ISPs were widespread, and -*** remaining IN member organizations could get decend connectivity with IN e.V. +*** remaining IN member organizations could get decent connectivity with IN e.V. == Internet @@ -254,10 +322,10 @@ This brought new purpose to leased lines == Analog Leased Lines * Telephone operator permanently interconnects wires at exchange -* No signaling (dialtone/ringtone etc) +* No signaling (dial tone, ring tone etc) * Requires modems with special capabilities ** ATA without an incoming ring first -** ATD without a dialtone first +** ATD without a dial tone first * In Germany: "Analog G" of Post/Telekom ** I finally could afford one in 1998 ** 900 DM installation cost @@ -267,12 +335,16 @@ This brought new purpose to leased lines image:images/pict3_Lg.jpg[] +== hub-nbg.franken.de, 1998 + +image:images/pict4_Lg.jpg[] == ISDN Leased Lines "SPV" * Not really a leased line * Basically only "flat rate calls" to one specific (fixed) destination * Available in national 1TR6 only +** some of them operated until 2006 == Abusing Analog Lines, Part 1 @@ -287,7 +359,7 @@ Easy upgrade to get performance of a leased ISDN line out of an Analog-G [graphviz] ---- -include::images/knf-leased_lines.dot[] +include::images/knf-leased_lines.dot[width="100%"] ---- == hub-fue.franken.de, undated @@ -300,10 +372,10 @@ image:images/hub-fue-04_Lg.jpg[] == Abusing Analog Lines, Part 2 -When the first DSL modems became availale in the US +When the first DSL modems became available in the US * we imported some Ascend DSLpipe -* with some fimrwares, they could be used back-to-back (without DSLAM) +* with some firmwares, they could be used back-to-back (without DSLAM) * suddenly we could get speeds of 2.3 MBps over analog lines ** if they were not too long ** if they didn't have in-line inductors @@ -324,11 +396,25 @@ image:images/ascend.jpg[width="50%"] ** ISDN SPV was used as Internet uplink +== Summary + +* The first decade[s] of wide-area electronics communications +** were powered by a community of enthusiasts +** largely motivated by non-commercial motives +** without much corporate or government influence +* BBS community / culture is a distinct sub-culture. +** different norms than HAM radio, Hackers, Free Software, but some of overlap + == Conclusions -* The first decade[s] of wide-area electronics communications was powered by a community of enthusiasts -* BBS community / culture is a distinct sub-culture. Different norms than HAM radio, Hackers, Free Software, but lots of overlap +In the BBS days +* networks were distributed, without single point of failure +* infrastructure **owned and operated by its users** +* connection speeds were largely symmetric +* no data center vs. consumer separation with asymmetric speeds + +This autonomy and de-centralization has been lost in the Internet age == Further Reading @@ -338,9 +424,22 @@ image:images/ascend.jpg[width="50%"] ** FOSS multi-platform terminal program * http://artscene.textfiles.com/ansi/ ** Archive of ANSI Artwork +* https://artpacks.org/ +** Another Archive of ANSI Artwork * http://www.filegate.net/nodelist/ ** FIDO nodelist of 2017 +* http://www.ka9q.net/code/ka9qnos/ +** Phil Karn's page on KA9Q NOS + +== Thanks + +* my uncle for giving me his old Olivetti acoustic coupler in 1990 +* Josef Groll, SysOp of SILVER.zer / SILVER.nbg.sub.org +* Max Riegel, Martin Bokaemper, Joerg Kinzebach and KNF crew +* Reinhold "unhold" Pretscher for Falken's Maze +* All sotware developers of BBS related software +* All SysOps that made the BBS community possible == EOF -End of File +NO CARRIER diff --git a/2017/bbs_early_internet-34c3/bbs_early_internet.css b/2017/bbs_early_internet-34c3/bbs_early_internet.css new file mode 100644 index 0000000..b17829c --- /dev/null +++ b/2017/bbs_early_internet-34c3/bbs_early_internet.css @@ -0,0 +1,31 @@ +div.change_topic { + display: flex; + align-items: center; + justify-content: center; +} + +div.change_topic h1 { + text-align: center; + border-bottom-width: 0px; +} + +div.gimmick_right img { + float: right; +} + +div.qanda ol { + list-style-type: none; +} + +.monospaced, code, pre { + color: black; + font-weight: bold; +} + +div.quoteblock, div.verseblock { + color: black; +} + +em { + color: black; +} diff --git a/2017/bbs_early_internet-34c3/bbs_early_internet.html b/2017/bbs_early_internet-34c3/bbs_early_internet.html index bacb74e..a1fc9df 100644 --- a/2017/bbs_early_internet-34c3/bbs_early_internet.html +++ b/2017/bbs_early_internet-34c3/bbs_early_internet.html @@ -3869,6 +3869,53 @@ setTimeout(w3c_slidy.hide_slides, 50); Harald Welte <laforge@gnumonks.org>
+

Introduction

+
+
    +
  • + +this is not a high-tech talk + +
  • +
  • + +way fewer acronyms than in mots of my other talks + +
  • +
  • + +I didn’t invent any of the technologies covered + +
  • +
  • + +I didn’t write any of the software covered + +
  • +
  • + +Just a mere user and operator/sysadming + +
  • +
  • + +.. this is the world I grew up in (age 11 onwards) + +
  • +
  • + +very limited information available in literature and on the WWW + +
  • +
  • + +lots of younger members of our community lack this history + +
  • +
+
+
+

Circuit Switched Telephony

    @@ -3911,19 +3958,50 @@ Telephone
  • -Copper wire +Copper wire[s]
  • -Telephone Exchange +Telephone Exchange[s] + +
  • +
+

+images/pots_fig10.2.png +

+
+
+
+

Phone Charges

+
+

In Germany during the 80ies and 90ies

+
    +
  • + +even local calls were metered / charged + +
  • +
  • + +flat rates didn’t exist + +
  • +
  • + +various zones between local and long distance + +
  • +
  • + +not many people could afford long distance BBSing
-

Accoustic Coupler

+

Acoustic Coupler

  • @@ -3950,11 +4028,11 @@ After call was established, both sides put receiver into coupler

    Modems

    -

    Automatization of the accoustic coupler

    +

    Automation of the acoustic coupler

    • -Avoid speaker/micrphone path +Avoid air gap speaker/microphone path
    • @@ -3969,6 +4047,14 @@ directly dial the phone number / answer the line

    +images/analogm.png +

    +
    +
    +
    +

    Modems

    +
    +

    images/Modems.jpg

    @@ -4058,6 +4144,44 @@ offering interactive service to users who dial in
+

To operate a BBS, you had to have

+
    +
  • + +a separate/dedicated computer + +
      +
    • + +most BBS software predated/predates multi-tasking OSs + +
    • +
    +
  • +
  • + +running 24/7 + +
  • +
  • + +attached to separate / dedicated phone line + +
  • +
+

To use a BBS, you

+
    +
  • + +power your computer when using it + +
  • +
  • + +can share your regular phone line with the modem + +
  • +
@@ -4106,7 +4230,7 @@ Both sides: Computer + Modem
  • -BBS Side +BBS Side Software
    • @@ -4116,14 +4240,14 @@ BBS Software
    • -often extended by "doors" (external programs, think of CGI for web) +often extended by "doors" (external programs, think of CGI in Web)
  • -User Side +User Side Software
    • @@ -4140,6 +4264,20 @@ Terminal Program (e.g. TELIX, Telemate for DOS)
  • +

    Demo

    +
    +

    Time for a demo

    +
    + + + +
    +
    Note
    +
    I’m using telnet instead of modem/dialup (POTS lines hard to find these days)
    +
    +
    +
    +

    The "BBS Protocol Stack"

    In the spirit of protocol stack diagrams…

    @@ -4256,6 +4394,7 @@ BBS can scale to more users this way

    BBS networks (store + forward)

    +

    As opposed to individual BBSs with isolated communities…

    Idea: Replicate bulletin / message boards between independent BBSs, for

    • @@ -4349,24 +4488,24 @@ Starts in 1984 with two BBSs
    • -Initial limit of 250 nodes reached in 1985 +Initial technological limit of 250 nodes reached in 1985
    • -Hierarchic, Regoinal routing/Adressing introduced in 1986 +Hierarchic, Regional routing/Addressing introduced in 1986
      • -Nodelist defines all nodes of the network + hierarchy +Nodelist defines all nodes of the network + hierarchy
    • -Addresses like "Harald Welte @ 2:2490/1343" +Addresses like Harald Welte @ 2:2490/1343
    • @@ -4405,7 +4544,7 @@ CrossPoint (DOS) most popular point software for ZConnect
    • -Addresses like H.WELTE@SILVER, later H.WELTE@SILVER.zer +Addresses like H.WELTE@SILVER, later H.WELTE@SILVER.zer
    @@ -4422,12 +4561,12 @@ Established in 1980 in the US
  • -Uses UUCP (Unix-to-Unix-Copy) as transport mechanism over Modmes +Uses UUCP (Unix-to-Unix-Copy) as transport mechanism over Modems
    • -UUCP was created in the 1970ies and used to copy files, including Internet Mal +UUCP was created in the 1970ies and used to copy files, including Internet Mail
    @@ -4439,9 +4578,21 @@ Usenet News format (RFC850) designed very similar to Internet Mail (RFC822)
  • -Hierarchy of News Groups that gets replicated / flooded accross the network +Hierarchy of News Groups that gets replicated / flooded across the network, e.g. + +
      +
    • + +comp.* — Discussion of computer-related topics like “comp.lang.c++” + +
    • +
    • + +sci.* — Discussion of scientific subjects
    • +
    +
  • Routing defined in route maps @@ -4453,7 +4604,7 @@ Routing defined in route maps

    Curiosity: Floppy Poll/Point

    -
      +
      • Not everyone had a phone line in the 1990ies @@ -4468,7 +4619,7 @@ particularly Eastern Germany had big lack of phone lines
      • -Some people thus exchanged daily floppies in evenlopes and mailed them as postal letters +Some people thus exchanged daily floppies in envelopes and mailed them as postal letters
      • @@ -4555,7 +4706,69 @@ you could run SLIP on both sides, transporting IP over the modem line
        • -IP. At home. In your apartment !!1! +Result: IP. At home. In your apartment !!1! + +
        • +
        +
      • +
      • + +later superseded by PPP (auto-configuration, authentication, compression, …) + +
      • +
      +

      Popular software stack looked like:

      +
        +
      • + +Windows 3.11 + Trumpet Winsock (Windows didn’t have TCP/IP!) + +
      • +
      • + +NCSA Mosaic as web-1.0 browser (1993 onwards) + +
      • +
      +

      +images/mosaic.jpg +

      +
    +
    +
    +

    Internet on PCs before Linux

    +
    +
      +
    • + +if you didn’t have a 386 or if Linux didn’t exist yet + +
    • +
    • + +there was KA9Q NOS + +
        +
      • + +Implementation of TCP/IP, SLIP, PPP for CP/M and DOS + +
      • +
      • + +POP3 + SMTP server + client, IP routing, telnet, ARP, etc. + +
      • +
      +
    • +
    • + +you could run SLIP on both sides, transporting IP over the modem line + +
        +
      • + +Result: IP. At home. In your apartment !!1!
      @@ -4670,7 +4883,7 @@ Grass-Roots groups of enthusiasts established themselves
    • -Kommunikationsnetz Franken e.V. (KNF, franken.de) one of them +Kommunikationsnetz Franken e.V. (KNF, “franken.de”) one of them
      • @@ -4739,7 +4952,7 @@ commercial ISPs were widespread, and
      • -remaining IN member organizations could get decend connectivity with IN e.V. +remaining IN member organizations could get decent connectivity with IN e.V.
      @@ -4779,7 +4992,7 @@ Telephone operator permanently interconnects wires at exchange
    • -No signaling (dialtone/ringtone etc) +No signaling (dial tone, ring tone etc)
    • @@ -4794,7 +5007,7 @@ ATA without an incoming ring first
    • -ATD without a dialtone first +ATD without a dial tone first
    @@ -4833,6 +5046,14 @@ I finally could afford one in 1998
    +

    hub-nbg.franken.de, 1998

    +
    +

    +images/pict4_Lg.jpg +

    +
    +
    +

    ISDN Leased Lines "SPV"

      @@ -4850,6 +5071,13 @@ Basically only "flat rate calls" to one specific (fixed) destination Available in national 1TR6 only +
        +
      • + +some of them operated until 2006 + +
      • +
    @@ -4903,9 +5131,17 @@ Special ISDN routers without signaling to use even 16k D-channel for data!
  • +

    hub-fue.franken.de, undated

    +
    +

    +images/hub-fue-04_Lg.jpg +

    +
    +
    +

    Abusing Analog Lines, Part 2

    -

    When the first DSL modems became availale in the US

    +

    When the first DSL modems became available in the US

    • @@ -4914,7 +5150,7 @@ we imported some Ascend DSLpipe
    • -with some fimrwares, they could be used back-to-back (without DSLAM) +with some firmwares, they could be used back-to-back (without DSLAM)
    • @@ -4990,12 +5226,53 @@ people started to dial into CompuServe, AOL, etc.
    • -Internet became more popluar, Falken’s Maze started subsidiary in Nuernberg +Internet became more popular, Falken’s Maze started subsidiary in Nuernberg + +
        +
      • + +ISDN SPV was used as Internet uplink + +
      • +
      +
    • +
    +
    +
    +
    +

    Summary

    +
    +
      +
    • + +The first decade[s] of wide-area electronics communications + +
        +
      • + +were powered by a community of enthusiasts + +
      • +
      • + +largely motivated by non-commercial motives + +
      • +
      • + +without much corporate or government influence + +
      • +
      +
    • +
    • + +BBS community / culture is a distinct sub-culture.
      • -ISDN SPV was used as Intenret uplink +different norms than HAM radio, Hackers, Free Software, but some of overlap
      @@ -5004,6 +5281,35 @@ ISDN SPV was used as Intenret uplink
    +

    Conclusions

    +
    +

    In the BBS days

    +
      +
    • + +networks were distributed, without single point of failure + +
    • +
    • + +infrastructure owned and operated by its users + +
    • +
    • + +connection speeds were largely symmetric + +
    • +
    • + +no data center vs. consumer separation with asymmetric speeds + +
    • +
    +

    This autonomy and de-centralization has been lost in the Internet age

    +
    +
    +

    Further Reading

    +
    +
    +
    +

    Thanks

    +
    +
      +
    • + +my uncle for giving me his old Olivetti acoustic coupler in 1990 + +
    • +
    • + +Josef Groll, SysOp of SILVER.zer / SILVER.nbg.sub.org + +
    • +
    • + +Max Riegel, Martin Bokaemper, Joerg Kinzebach and KNF crew + +
    • +
    • + +Reinhold "unhold" Pretscher for Falken’s Maze + +
    • +
    • + +All sotware developers of BBS related software + +
    • +
    • + +All SysOps that made the BBS community possible + +

    EOF

    -

    End of File

    +

    NO CARRIER

    diff --git a/2017/bbs_early_internet-34c3/bbs_early_internet__1.png b/2017/bbs_early_internet-34c3/bbs_early_internet__1.png new file mode 100644 index 0000000..c1172fc Binary files /dev/null and b/2017/bbs_early_internet-34c3/bbs_early_internet__1.png differ diff --git a/2017/bbs_early_internet-34c3/images/analogm.png b/2017/bbs_early_internet-34c3/images/analogm.png new file mode 100644 index 0000000..acca908 Binary files /dev/null and b/2017/bbs_early_internet-34c3/images/analogm.png differ diff --git a/2017/bbs_early_internet-34c3/images/mosaic.jpg b/2017/bbs_early_internet-34c3/images/mosaic.jpg new file mode 100644 index 0000000..502b582 Binary files /dev/null and b/2017/bbs_early_internet-34c3/images/mosaic.jpg differ diff --git a/2017/bbs_early_internet-34c3/images/pict4_Lg.jpg b/2017/bbs_early_internet-34c3/images/pict4_Lg.jpg new file mode 100644 index 0000000..2a78f0e Binary files /dev/null and b/2017/bbs_early_internet-34c3/images/pict4_Lg.jpg differ diff --git a/2017/bbs_early_internet-34c3/images/pots_fig10.2.png b/2017/bbs_early_internet-34c3/images/pots_fig10.2.png new file mode 100644 index 0000000..cb9acdb Binary files /dev/null and b/2017/bbs_early_internet-34c3/images/pots_fig10.2.png differ -- cgit v1.2.3