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Re: OT: ANS Forth

From Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups comp.lang.forth
Subject Re: OT: ANS Forth
Date 2013-02-24 03:03 +0100
Organization 1&1 Internet AG
Message-ID <kgbse2$m1a$1@online.de> (permalink)
References (7 earlier) <7xip5mkrew.fsf@ruckus.brouhaha.com> <sP-dncPLPuFUQrjMnZ2dnUVZ_oGdnZ2d@supernews.com> <7xzjyyrq3v.fsf@ruckus.brouhaha.com> <kg5570$c8e$1@online.de> <7xk3pzpg68.fsf@ruckus.brouhaha.com>

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Paul Rubin wrote:
> Finally, instrument the "outside world" object to log all the events
> going out, so you have a captured trace when packets are lost.  Use the
> mock object to play this trace back into the flow control algorithm.
> Now you can use a single-step debugger (or some other method) to see
> where the flow control algorithm is going wrong.

Actually, I just do the tracing inside, and do the outside world with 
standard reality, no simulator needed.  Do you know how your wireless 
rounter reacts on congestions, how its buffers fill up, and how often a 
random packet gets dropped?  I don't, or let's say: I didn't.  Writing a 
simulator instead of using reality is often a waste of time.  But only so, 
if you actually record and keep what you measured from reality.

As Andrew Haley said, reality is usually so complex that you don't want to 
write an accurate simulator.  And you have to understand reality and 
optimize for real conditions, instead for simulated ones.  TCP behaves 
rather nice on network simulators.  It behaves rather worse in reality, and 
the people who designed TCP show their lack of understanding by naming the 
TCP problems "buffer bloat" and such, indicating that they are looking for 
someone else to take the blame.  net2o wants to fix the real problems, not 
the simulated ones.  Buffers are good, and packet drops in WLANs are 
unavoidable, and just one problem.  Speed changes due to signal strength 
changes happen very frequently.

Just for comparison:  When I started the flow control debugging, I simply 
had the programs running on two machines (connected by WLAN and DSL lines), 
collecting informations on both sides - that's the typical setup most 
internet users have today.  The test data was ~10 megabytes large (the 3 
seconds with 3MB/s over WLAN), the collected information below 100k.  And I 
used scp to get the data back to my local machine, for analysis.  The scp 
did usually take longer than the net2o test run.  Both net2o and scp do 
roughtly the same thing: Transfer files with an encrpyted and authenticated 
protocol, using a key exchange at the beginning and symmetric encryption for 
the rest, with a flow control that aims to use the achievable bandwidth.  
The difference is that net2o establishes the encrypted connection in a 
standard handshake together with everything else (including asking for the 
files to transfer), and needs just one further RTD to get up to full speed.  
And then it doesn't let itself disturb by random garbled WLAN packets.

You don't get there without looking at reality.  This is a very Forth-ish 
approach at programming: You have to understand the problem to solve it, so 
your way to solution not only involves solving the problem itself, but also 
to analyze the problem, for a better understanding of its nature.

To be honest: I significantly underestimated the effort of the flow control.  
When I started, I thought algorithms like LEDBAT did solve the problems.  
And then I tried them and they don't.  Back to the drawing board.  And then, 
I figured out that to achieve fairness with a dead simple algorithm, you'd 
need a really simple change in the buffer handling of the router - but the 
router is off limits for the first deployment of net2o, it absolutely must 
work with today's routers, and offer as many advantages as possible.  So, 
with the random buffer policy of today's routers and switches, this was 
really tricky.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

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3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 22:51 +0100
  Re: 3D-graphics calculations using integers? "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-07 22:08 +0000
  Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 14:32 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:40 +0100
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:06 -0800
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:07 -0800
  Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-07 14:36 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:46 +0100
      Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 16:38 -1000
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 10:22 +0100
      Re: 3D-graphics calculations using integers? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-08 10:26 +0000
  Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 12:50 -1000
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:15 +0100
      Re: 3D-graphics calculations using integers? kenney@cix.compulink.co.uk - 2013-02-08 14:51 -0600
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:02 +0100
  Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:21 -0500
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:30 +0100
      Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:39 +0100
        Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:51 -0500
          Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 12:28 +0100
            Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-08 12:25 +0000
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:04 +0100
                Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-09 15:27 +0000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:36 +0100
            Re: 3D-graphics calculations using integers? Mark Wills <forthfreak@gmail.com> - 2013-02-08 05:01 -0800
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 21:58 +0100
            Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:08 -0500
              Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:11 -0500
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:05 +0100
              Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-08 08:29 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 18:48 +0100
            Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-08 17:20 -0500
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 23:32 +0100
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-09 23:57 -0500
              Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:02 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 02:24 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:58 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:43 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:03 -1000
                Re: 3D-graphics calculations using integers? "Ed" <invalid@nospam.com> - 2013-02-10 11:35 +1100
                Re: 3D-graphics calculations using integers? humptydumpty <ouatubi@gmail.com> - 2013-02-08 23:48 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:37 +0100
                OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 17:27 +0100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:06 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-09 12:26 -0800
                Re: OT: ANS Forth Elizabeth D Rather <erather@forth.com> - 2013-02-09 14:38 -1000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 12:52 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-22 09:25 -1000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-10 08:15 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 23:34 -0800
                Re: OT: ANS Forth Josh Grams <josh@qualdan.com> - 2013-02-11 22:14 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-11 13:34 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-11 11:52 +1100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 17:11 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-10 22:06 -1000
                Re: OT: ANS Forth "Charles Childers" <crc@retroforth.org> - 2013-02-11 17:17 -0500
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-13 11:42 +1100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-12 16:07 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-15 09:42 +1100
                Re: OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-15 00:16 +0100
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-17 16:05 +1100
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 04:16 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-17 13:12 +0000
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 09:15 -0800
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-19 09:35 -0800
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 19:25 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 15:35 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:37 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 23:07 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 08:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:44 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 03:41 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 20:00 -0800
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-24 13:49 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 15:04 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 14:52 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 23:51 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 16:23 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 03:55 -0600
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 13:01 -0500
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-22 12:26 -0600
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 21:54 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 18:21 -0600
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-20 08:45 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-20 11:01 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 11:25 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:22 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 22:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:08 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-21 12:42 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:50 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:36 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:32 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:50 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 03:03 +0100
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-21 09:12 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:01 -1000
                Re: OT: ANS Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-22 00:05 +0200
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:24 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:33 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 13:04 -0600
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:41 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:31 -0800
                Re: OT: ANS Forth "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-23 09:15 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:33 -0600
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:49 +0000
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:35 -0500
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:46 -0500
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:26 -0800
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-24 09:41 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:09 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:37 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:57 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-23 08:47 -1000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:27 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:16 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:36 -0600
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-23 16:52 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 12:39 -0800
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 16:27 +0000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-23 18:08 -0500
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 02:20 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 20:16 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:04 +0100
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-25 17:12 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:44 +0100
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:45 +0100
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-24 02:09 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 04:03 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 17:58 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:57 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-02 16:43 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-03-02 18:14 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-03 13:56 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-24 03:45 -0600
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-13 04:12 -0600
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-13 12:24 +0000
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-11 14:41 +0000
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-11 19:44 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-11 21:14 +0000
                Re: 3D-graphics calculations using integers? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-09 18:14 -0600
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-10 00:06 -0500

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