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program to compute gears, with table



 
 
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  #121  
Old September 22nd 17, 02:27 AM posted to rec.bicycles.tech
[email protected]
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Posts: 3,346
Default program to compute gears, with table

On Thursday, September 21, 2017 at 2:31:14 PM UTC-7, Emanuel Berg wrote:
wrote:

So every program that is written in high
level languages is a chance for some
unethical hacker to control something that
is yours.


Hackers (or crackers) cannot control anything
just because it is written in
a certain language.

Most Unix tools are written in C and virtually
everything, including the kernel, is written in
high level languages. The source code is
compiled into executables that cannot be
executed by outsiders.

Hackers-crackers cannot gain access to a system
by outsmarting the technology, they can only
outsmart people who give away their passwords,
carelessly install malware they get in spam,
and so on. It is a game of "you cannot fool
everyone, but you can fool some, and those are
the ones you should focus on".


Well, we'll have to differ on this. Everything is updated via the Internet these days including things like the control software for a Tesla. The most difficult password systems in the world can be broken with quantum computers. And those things calculate probabilities and not actualities as a normal computer does.

There is an entire underworld of possible control and a great deal of it is based on errors introduced by higher level languages.

Are you aware that the Americans cracked the software in the uranium centrifuges in Iran and was able to make them break down?
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  #122  
Old September 22nd 17, 04:38 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 417
Default program to compute gears, with table

wrote:

Well, we'll have to differ on this.
Everything is updated via the Internet these
days including things like the control
software for a Tesla.


Well, I use the Debian repositories for
software and upgrades, and I suppose that
counts as "via the Internet", but unless those
archives are compromised it should be safe.

There are also systems of verification, hashes,
checksums, and such, not that I ever bothered,
but there are people who are more
paranoid/careful or have just taken an active
interest in computer security who do that
every time.

The most difficult password systems in the
world can be broken with quantum computers.
And those things calculate probabilities and
not actualities as a normal computer does.


Brute force attacks, no matter the level of
sophistication, still require that many, many
such attempts can be made. It's a big operation
to carry it out from many laps around the world
and compile the results because a fraction of
those attempts from a single source or in
a short time-frame should raise a red flag at
the admin's HQ.

There is an entire underworld of possible
control and a great deal of it is based on
errors introduced by higher level languages.


The only such language specific vulnerability
I'm aware of is the so called seekwell
injection. SQL, a domain-specific query
language (relational algebra) used for
databases, anyway it prompts the user for
input, like ask for a name, only the user
(hacker-cracker) inputs SQL commands, which the
database executes, which worst-case can bring
the system down instantly even with a trivial
error (e.g., division by zero). However scary
this might sound, if the database just
quotes/escapes the input - automatically, every
time, most likely by a single line of code -
then the system can't be harmed that way.

Are you aware that the Americans cracked the
software in the uranium centrifuges in Iran
and was able to make them break down?


The little I know of that is that they had
access to very specific details from the guys
who built it - Germans? I don't remember.

--
underground experts united
http://user.it.uu.se/~embe8573
  #123  
Old September 22nd 17, 08:15 AM posted to rec.bicycles.tech
dave[_3_]
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Posts: 28
Default program to compute gears, with table

On Fri, 22 Sep 2017 05:38:43 +0200, Emanuel Berg wrote:

wrote:

Well, we'll have to differ on this. Everything is updated via the
Internet these days including things like the control software for a
Tesla.


Well, I use the Debian repositories for software and upgrades, and I
suppose that counts as "via the Internet", but unless those archives are
compromised it should be safe.

There are also systems of verification, hashes,
checksums, and such, not that I ever bothered, but there are people who
are more paranoid/careful or have just taken an active interest in
computer security who do that every time.

The most difficult password systems in the world can be broken with
quantum computers. And those things calculate probabilities and not
actualities as a normal computer does.


Brute force attacks, no matter the level of sophistication, still
require that many, many such attempts can be made. It's a big operation
to carry it out from many laps around the world and compile the results
because a fraction of those attempts from a single source or in a short
time-frame should raise a red flag at the admin's HQ.

There is an entire underworld of possible control and a great deal of
it is based on errors introduced by higher level languages.


The only such language specific vulnerability I'm aware of is the so
called seekwell injection. SQL, a domain-specific query language
(relational algebra) used for databases, anyway it prompts the user for
input, like ask for a name, only the user (hacker-cracker) inputs SQL
commands, which the database executes, which worst-case can bring the
system down instantly even with a trivial error (e.g., division by
zero). However scary this might sound, if the database just
quotes/escapes the input - automatically, every time, most likely by a
single line of code - then the system can't be harmed that way.

Are you aware that the Americans cracked the software in the uranium
centrifuges in Iran and was able to make them break down?


The little I know of that is that they had access to very specific
details from the guys who built it - Germans? I don't remember.



There are a shed load of ways to get into computers from outside.
Unpatched vulnerabilities all over the place.

https://metasploit.com/

Deephack AI cracking https://www.youtube.com/watch?v=wCky_QCEzHU
Machine learning. It learns as it goes along... Which is nice.

No matter what language software is written in there will always be
errors. System complexity is so high that there is always going to be
something missed. A small thing with some unexpected consequence which
leads to a bigger thing and so on.

You claim to use Debian so you must be well aware of this small problem
spreading business every time you do "apt-get update to not working".

I sincerely hope you are not in charge of security at Zoho or are lying
about your email address. It's never good for a computer services company
to have their staff running around sounding clueless on the internet.

Anyway to return to a more bike related question. Who is going to be the
first to install Linux on a bike? Things are getting pretty hi-tech now.
--
davethedave
  #125  
Old September 22nd 17, 08:16 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 417
Default program to compute gears, with table

dave wrote:

You claim to use Debian [...]

I sincerely hope you are not in charge of
security at Zoho or are lying about your
email address.


I make unsupported claims about my OS and might
be lying about my e-mail as well... It is
a good thing security-aware people like you
aren't fooled that easily.

--
underground experts united
http://user.it.uu.se/~embe8573
  #126  
Old September 22nd 17, 08:19 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 417
Default program to compute gears, with table

Doug Landau wrote:

Hackers (or crackers) cannot control
anything just because it is written in
a certain language.


The truth of this statement is a function of
time There have been time-language pairs for
which this is not true


Do you or anyone else have an example of how
anyone got remote and full access to a computer
system simply because a program was written in
a particular language?

If so, at least my system is wide open for
attacks because I dare say I have at least one
program written in every single major language
there is.

For example, in this very thread I posted
a program in Elisp with some extras from CL.
It would be interesting to know how that
exposes my computer to the outside world and
how hackers-crackers can use it to gain access
to my system?

--
underground experts united
http://user.it.uu.se/~embe8573
  #127  
Old September 23rd 17, 05:37 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 417
Default program to compute gears, with table

Andre Jute wrote:

Why are you making it so complicated?
At
http://coolmainpress.com/BICYCLINGHebieChainglider.html
you can see how simple I made it in Excel.


BTW, what formula did you use?

I made one change, shouldn't the tire be
counted twice when one computes the diameter?

Do you get the same data for the same
configuration, which is:

chainrings 34 50T
sprockets 12 13 15 17 19 21 23 25T
bsd 622 mm
tire 23 mm

Better compare notes carefully after all...

BSD: 622 mm
ti 23 mm
wheel: 622 + 2*23 = 668 mm
roll-out = chainring/sprocket * wheel

chainring sprocket roll-out

34 25 2854.1
34 23 3102.3
34 21 3397.7
34 19 3755.4
50 25 4197.2
34 17 4197.2
50 23 4562.1
34 15 4756.8
50 21 4996.6
34 13 5488.6
50 19 5522.6
34 12 5946.0
50 17 6172.3
50 15 6995.3
50 13 8071.5
50 12 8744.1

--
underground experts united
http://user.it.uu.se/~embe8573
  #128  
Old September 23rd 17, 06:42 AM posted to gnu.emacs.help,rec.bicycles.tech
DougC
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Posts: 1,276
Default program to compute gears, with table

On 9/9/2017 9:06 PM, David Scheidt wrote:
,,,

On my mac at work, from the time I double click the excel icon to the
time it is ready to do work is over a minute. It's a modern machine,
running an old version of excel. The windows machine I have, but
never use, which is more powerful, and running a current version,
takes even longer. It does have a spinny disk, and not an ssd.
(that's not counting the time to takes to boot up, since it's off.)


Your Mac/PC/Excel experience seems slow.
I don't use Office at work and use LibreOffice at home now, so I don't
really know how bad the rental version of MS Office is these days.

I have not written nor used a CLI program in many years. I'd rather do
it in a GUI (Visual Basic) just for the copy & paste ability that comes
along for free. PCs are so big and fast now that there's little point in
worrying about saving a few kilobytes--or even, a few hundreds of
kilobytes. And arguing that a CLI is somehow "better" than a GUI is like
arguing that a well and an outhouse are somehow "better" than indoor
plumbing.

Also I have written programs in the past and not included any help
files, and then forgotten how to use them. With the VB programs, I put
in a few help buttons + message boxes that explain how to use the thing,
so the help can't ever get separated from the program it goes with...
  #129  
Old September 23rd 17, 07:41 AM posted to gnu.emacs.help,rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 417
Default program to compute gears, with table

DougC wrote:

I have not written nor used a CLI program in
many years. I'd rather do it in a GUI (Visual
Basic) just for the copy & paste ability that
comes along for free.


You can copy and paste, or "kill and yank" as
it is called in the Emacs world, writing CLI
programs as well. But actually it is a bad
habit. The same code shouldn't appear twice.
Instead, it should be "factored out" as it is
called, i.e. put into a neat little function of
its own, and then be invoked, the same
function, from anywhere where it is needed.

PCs are so big and fast now that there's
little point in worrying about saving a few
kilobytes--or even, a few hundreds
of kilobytes.


CLI programming is not because the programs are
smaller on the disk. Which they are, of course.
It is about other things - speed, creativity,
and the simple fact that some people don't like
clicking on icons with a mouse and pointer, or
searching in endless menus for what the want to
do. They like typing and text and combining
tools to do whatever. This way, one can just
use the computer at a whole other level.

Also, the GUIs are not esthetically appealing
to these people - when you understand what goes
on behind it, just looking at it can be an
unpleasant thing. Text on the other hand is the
truth, there is nothing manipulative to it.
The real deal.

And arguing that a CLI is somehow "better"
than a GUI is like arguing that a well and an
outhouse are somehow "better" than
indoor plumbing.


CLIs, or text interfaces in general, are
better, faster, more reliable in almost every
case, the exception being applications that are
graphical in nature, e.g. GIS, scientific
visualization programs, and such.

However, not all applications which to some
extent are graphical needs a GUI - examples
here are LaTeX and gnuplot, where very
good-looking documents, charts, and diagrams
can be produced straight from a text buffer.

Also I have written programs in the past and
not included any help files, and then
forgotten how to use them. With the VB
programs, I put in a few help buttons +
message boxes that explain how to use the
thing, so the help can't ever get separated
from the program it goes with...


No comments

--
underground experts united
http://user.it.uu.se/~embe8573
  #130  
Old September 24th 17, 02:05 AM posted to gnu.emacs.help,rec.bicycles.tech
Joy Beeson
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Posts: 1,009
Default program to compute gears, with table

On Sat, 23 Sep 2017 00:42:38 -0500, DougC
wrote:

And arguing that a CLI is somehow "better" than a GUI is like
arguing that a well and an outhouse are somehow "better" than indoor
plumbing.


Private wells are still around, and a properly-constructed long-drop
dunny is vastly superior to a portapotty.

--
Joy Beeson
joy beeson at comcast dot net
http://wlweather.net/PAGEJOY/

 




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