The h Bar

Phase

00:15

Turns out fetlife isn't the place for physics discussions to flourish

who would've figured

Cows

01:02

Ha . . . I can't make my answer pass all test cases. Let me just grab a burrito first

Ok I am listening to Enya right now and solving this problem (duplicates) I think I can pass all the test cases, especially since I don't live in Rindler space

loocsieulb

01:25

@Phase thanks for the heads up i'll keep that in mind

Cows

02:39

Crap!!!!!!! Execution time limit exceeded

Will relax by reading about black hole information hehe (yes I said it lol :P)

@BernardoMeurer can you help me do this in O(n) time, O(1) space and in minimal execution time. I am trying to find duplicates. My firtst working pass is this function firstDuplicate(a){

var temp = [];

for (var i = 0; i < a.length; i++){
for (var j = 0; j < a.length; j++){

if( a[i] === a[j] && i != j ) {

if(i<j){
temp.push(j);
}

}

}
}

if(temp.length === 0){
return -1;
}

var sorted = temp.sort();
return a[(sorted[0])];

}

Bernardo Meurer

@Cows That is some hideous formatting

And I have no clue what that code is supposed to do or what language it is in

Are you trying to dedup an array?

Is that it

Cows

yup

I think the site did horrible formating

hang on let me give you a link so we can explore the code together

Bernardo Meurer

Are you concerned with time complexity or space complexity?

You kind of have to pick one here

Also, can we assume the array to be sorted, or no?

@Cows ?

Cows

yeah that is what i was thinking, but they want all those constraints too. Presumably there is a trick. lol I don't know what it is

Bernardo Meurer

So you want it to be low time and low memory?

Cows

02:51

@BernardoMeurer Note: Write a solution with O(n) time complexity and O(1) additional space complexity, since this is what you would be asked to do during a real interview.

Given an array a that contains only numbers in the range from 1 to a.length, find the first duplicate number for which the second occurrence has the minimal index. In other words, if there are more than 1 duplicated numbers, return the number for which the second occurrence has a smaller index than the second occurrence of the other number does. If there are no such elements, return -1.

Guaranteed constraints:
1 ≤ a.length ≤ 10^5,
1 ≤ a[i] ≤ a.length.

Bernardo Meurer

Traverse the array. Do following for every index i of A[].
{
    check for sign of A[abs(A[i])] ;
    if positive then        make it negative by   A[abs(A[i])]=-A[abs(A[i])];
    else  // i.e., A[abs(A[i])] is negative
    this   element (ith element of list) is a repetition
}

Cows

hmm let me see if I can get a shareable online editor so we can try this

I tried something similar but it failed 4 test cases and the edge cases

@BernardoMeurer Let's try it here

jsfiddle.net/#&togetherjs=QCPGne0ANI

@BernardoMeurer actually that editor does not work well

Bernardo Meurer

Yeah, it doesn't

Cows

@BernardoMeurer can you write an example in c++?

Bernardo Meurer

Look, the algorithm I outlined has the requirements

No. I can write a C example

Cows

02:58

that will be good too

please don't use pointers lolz, those things scare me

Bernardo Meurer

#include <stdio.h>
#include <stdlib.h>

void printRepeating(int arr[], int size)
{
  int i;

  printf("n The repeating elements are");

  for(i = 0; i < size; i++)
  {
    if(arr[abs(arr[i])] > 0)
      arr[abs(arr[i])] = -arr[abs(arr[i])];
    else
      printf(" %d ", abs(arr[i]));
  }
}

int main()
{
  int arr[] = {1, 3, 2, 2, 1};
  int arr_size = sizeof(arr)/sizeof(arr[0]);
  printRepeating(arr, arr_size);
  getchar();
  return 0;
}

From: geeksforgeeks.org/?p=7953

Cows

oh nice

Bernardo Meurer

That's not good C code though, I didn't bother to change it

And if you're scared of pointers you ought to grasp them before trying to achieve complex array manipulation

And also, the whole thing is a trick question, if you're worried about duplicates you should use a Hashset and have them ignored at insertion time

0celo7

@BernardoMeurer yo

sup

Bernardo Meurer

@0celo7 What uuuuuup

0celo7

03:04

nephews got baptized this weekend

Bernardo Meurer

Nice!

Cows

Ok cool knocked that out

Bernardo Meurer

I might be going to NY and DC in July-ish

I'll try to see you

0celo7

In July I'll be in Knox or Chicago

Not sure

Bernardo Meurer

Dam

We can't fucking meet

0celo7

03:06

@BernardoMeurer Do I need a visa when I go to Rio in Aug?

Bernardo Meurer

Ye

0celo7

fuck

Bernardo Meurer

It's easy to get tho

0celo7

how do I do that

Cows

@BernardoMeurer can you give me a quite run through of linked lists?

0celo7

03:07

@BernardoMeurer are you not gonna be in Rio during the beginning of Aug?

I'll be in the Baja area

Bernardo Meurer

@0celo7 travel.state.gov/content/travel/en/international-travel/…

@0celo7 Nothing set yet

I was waiting on your schedule to make mine

Cows

I want to attack a cs problem on it but I want to see if may be you can give me some insights about this stuff

Bernardo Meurer

I should go see my mother in NY for a week or so

Then I'm free

I was planning on going home in August when you go

0celo7

@BernardoMeurer thanks

Bernardo Meurer

@Cows Linked lists are absolute this, and almost useless

Cows

03:08

*singly linked . .

Bernardo Meurer

Give me a second, I have an article

@Cows cglab.ca/%7Eabeinges/blah/too-many-lists/book/…

0celo7

@BernardoMeurer cool, cool

Cows

wow

0celo7

Rio seems to be crazy

Bernardo Meurer

@Cows If you think you need linked lists, odds are you don't

Use a Hashmap, a Hashset, a B+ Tree, a Quadtree, an array, a rope, anything

@0celo7 Rio is insane

I shaved a guy's head in a party over new years

And I had sex on top of a fork and got my ass pierced

It's fun

0celo7

03:10

@BernardoMeurer the author of amazon.com/Algebraic-Topology-Edwin-H-Spanier/dp/0387944265 was robbed at gunpoint 3 times in 6 months while in rio

Bernardo Meurer

Oh and I got to set people's new year resolutions on fire too

@0celo7 When was that?

0celo7

in the 60s I think

Bernardo Meurer

Ah, yeah

It was a whole other city back then

0celo7

@BernardoMeurer I changed the formatting of my thesis

Bernardo Meurer

@0celo7 Send it my way

0celo7

03:16

@BernardoMeurer done

Bernardo Meurer

@0celo7 How come it's not dedicated to me

I am offended

0celo7

Cuz Bob buys me books

skullpatrol

who's Bob?

0celo7

no one you need to know

@BernardoMeurer basically pages 5-19 are done

do you like the font?

skullpatrol

You were supposed to answer "my uncle"

en.wikipedia.org/wiki/Bob%27s_your_uncle?wprov=sfti1

Bernardo Meurer

03:25

Yeah, I do like the font :)

It looks very nice

0celo7

@BernardoMeurer thanks, many hours were spent doing that

Cows

Implementing linked list in javascript

then will use it to solve some problem in O(n)

time

0celo7

@BernardoMeurer this is volume 1 of my manifesto

Bernardo Meurer

@Cows Use a hashset

You don't need a linked list

vzn

05:01

← still reeling from todays wild chat session, but wanted to thank all the well-intentioned SE mods who work hard to make SE a great place in cyberspace, incl esp all those who got their msgs deleted... am dedicating this song to you :) metrolyrics.com/shiny-happy-people-lyrics-rem.html

0celo7

05:29

@Slereah did you write this arxiv.org/abs/1802.04362

Cows

@0celo7 what's up with this gluing of spacetime everyone is doing these days?

0celo7

@Cows why not?

Cows

@0celo7 well, how does it work?

loocsieulb

07:17

@Cows depends what kind of glue

haha yes

Balarka Sen

07:59

@0celo7 Mike sent me this. See theorem 3.1 section 3

Sounds like what I want but over the free loopspace instead of the pathspace

Maybe there's some nontrivial functional analytic fuckery here

Slereah

08:09

@0celo7 doesn't seem like my style

Slereah

08:19

@vzn that's a tiny ass atom

2

Slereah

08:47

Oh man

I have the perfect answer for a post

But it would get deleted

0

Q: Greatest possible symmetry group of Lagrangian

I have two very specific questions regarding the symmetry group of a lagrangian. N Complex Scalars, massive, non-interacting Do we have a global U(N) symmetry, or a global O(2N) symmetry? 1 Fermion, Massless, non-interacting I have the idea that the symmetry group should be $U(1) \times U(1)_...

I wish to answer it with

Sliders - Professor Maximillian Arturo

►

"The largest symmetry group of a single Dirac field is... $\operatorname{U}(4)$!"

Qmechanic

09:32

0

Q: Nonlinear dyanmics and chaos theory in Electrical systems and circuits

Is there a possible application of the field of chaos theory and nonlinear dynamics in electrical systems such as circuits and power? If so, are they based on conventional nonlinear dynamics or are they more based on electromagnetic theory?

electromagnetism electric-circuits chaos-theory non-linear-systems

Too broad?

Slereah

@BalarkaSen does this seem alright

0

A: Discontinuity of metric derivatives in the Israel junction formalism

I am you from the future. Here's a probably fine argument for this. Take the normal bundle of the hypersurface $N = (-1, 1) \times \Sigma$, with the adapted coordinates $(r, y)$ such that $\partial_r$ is a vector normal to the hypersurface. We can decompose the metric tensor as $$g = g(\partia...

Qmechanic

1

Q: Most efficient way to learn simple formulas by heart without understanding

Is there an unorthodox way to memorize formulas for daily use, similar to the assimilation of multiplication tables in primary school? I included 'without understanding' because I do understand the formulas: given pen and paper and time to think (about the physics involved and/or dimensions) I ca...

soft-question education mathematics

Primarily opinion-based?

Slereah

@Qmechanic Well you could test for efficiency

skullpatrol

09:53

Good question for physics-education.SE :P

Mithrandir24601

@Slereah It's an individual thing though - what works best for one person might not for the next

Slereah

that is why you use statistics

also individuality is an illusion

Slereah

10:11

Great flag

Emilio Pisanty

10:35

This post (v2) seems like a list question. — Qmechanic ♦ 1 hour ago

@Qmechanic Can you look over my latest question on meta?

Slereah

"Western observers of Soviet science often spoke of the "blackboard rule," meaning that their Soviet colleagues could be expected to excel on those topics where world-rank work could be done with tools no more complicated than blackboard and chalk."

Emilio Pisanty

-2

A: Why is the damping force proportional to $v$ and not $v^2$?

maybe look into Persepolis by Marjane Satrapi or 1984 by George Orwell.

^ that's a new one

Secret

Hmm, I guess that might explain why professors of russian lineage like to teach with blackboards...

Emilio Pisanty

ditto with this one by the same user

-3

A: How to model a non-linear pendulum with air resistance?

maybe look into Einstein's work. Seems applicable here. Or another option is to go to bed.

Kyle Kanos

10:56

@mods: i accidentally flagged a post as 'rude or abusive' last night b/c the mobile app sucks for people with thick fingers

hope that doesn't confuse

skullpatrol

Yeah, it's not made for the members of the big hands club :P

Neither was electronics...

Slereah

12:29

"This view was challenged by Erich Kretschmann (1917), who argued that every theory of space and time (even including Newtonian dynamics) can be formulated in a covariant way, if additional parameters are included, and thus general covariance of a theory would in itself be insufficient to implement a generalized relativity principle."

Kretschmann the first to call out the diffeomorphism scam

John Rennie

I think that's a bit unfair. General covariance isn't enough on it's own, but if you consider it an essential component the GR pretty much falls into your lap.

Slereah

SR is generally covariant :p

if you allow arbitrary frames

John Rennie

Didn't Cartan formulate Newtonian gravity in a covariant way?

Slereah

yes

It's in MTW

John Rennie

Presumably in one of the chapters that no-one reaches because they died of exhaustion first

I think I read about it in Penrose's book

Slereah

12:36

I usually carry around physics books to read them on the bus

but I did not dare do it for MTW

"Consequently, Felix Klein (1910) called it the "invariant theory of the Lorentz group" instead of relativity theory, and Einstein (who reportedly used expressions like "absolute theory") sympathized with this expression as well"

Bit of a mouthful

"Other pseudo-Kantians like Ernst Cassirer or Hans Reichenbach (1920), tried to modify Kant's philosophy. Subsequently, Reichenbach rejected Kantianism at all and became a proponent of logical positivism."

the power of GR

"Some proponents of Philosophy of Life, Vitalism, Critical realism (in German speaking countries) argued that there is a fundamental difference between physical, biological and psychological phenomena. For example, Henri Bergson (1921), who otherwise was a proponent of special relativity, argued that time dilation cannot be applied to biological organisms, therefore he denied the relativistic solution of the twin paradox."

Ahah what

"Pierre Duhem regarded relativity as the product of the "too formal and abstract" German spirit, which was in conflict with the "common sense"."

@ACuriousMind is that the German spirit

Qmechanic

13:40

0

Q: Is it possible to form modern physics using entirely "classical" theory?

Each of the big theories of modern physics have a somewhat more "classical" equivalent, that is The Lorentz aether theory for special relativity The Bohm theory for quantum mechanics Pauli-Fierz theory for general relativity (the non-linear version of it, anyway) I'm not 100% sure that they a...

quantum-mechanics general-relativity special-relativity aether bohmian-mechanics

Off-topic as non-mainstream physics?

Slereah

I'd say no

This guy sounds like a proper gentleman

Also all three of those theories are properly mainstream theories, as defined in the rules

Qmechanic

@Slereah : Ha-ha :)

Slereah

a bit obsolete but most definately mainstream

Been reading about SR history so I wondered about the status of the Lorentz ether theory :p

Also hopefully this post will make Lubos Motl angry

"Beginning in the second third of the nineteenth century it was argued by American scientists such as Joseph Henry that while there was a great deal of activity devoted to inventions and the creation of practical implements, Americans were indifferent to basic science and basic research. "

So things didn't change that much it seems

"L.T. More, Professor of Physics at the University of Cincinnati, teased relativists on the grounds that if they were right then the sun was melting away at an incredible rate and that when a man caught a baseball, the mass of both the ball and the man's hand should change."

Curio

14:00

Do I have to indicate the dipole in a covalent dative bond?

Captain Bohemian

I read from Quora American universities focus more on engineering than fundamental sciences.

Curio

Why am I getting 0 answers these days?

Captain Bohemian

Maybe that's the case because I recall I read a PhD program in USA requires physics doctoral graduates to be familiar with both theoretical subjects and experiemtal subjects.

Curio

I mean here

Captain Bohemian

We haven't had any experimental courses since master; the purpose of my touching experiments is only to teach first year undergraduate students.

But I think engineering graduates are better at teaching those experiments. The both instructors whose courses I served as a teaching assistant are PhD graduates in engineering; they both know much about electronics which I don't know.

Emilio Pisanty

14:21

brought to you courtesy of SMBC over at smbc-comics.com/comic/wise-master

Semiclassical

lol

I'm always fond of this one:

smbc-comics.com/comic/know-your-linguistic-philosophies

Emilio Pisanty

Semiclassical

lol

(especially when it involves snark on the internet. and that's probably all I should say :P )

Slereah

the best is of course

smbc-comics.com/comic/2009-03-10

Emilio Pisanty

bahfest.com hmmm, tempting.

@Slereah that's not even a joke

Semiclassical

14:26

@EmilioPisanty huh, the upcoming MIT one has Max Tegmark as a judge

Emilio Pisanty

I mean, substitute splork for zilch and you get a legit physics concept

Slereah

Splorkions

Emilio Pisanty

@Slereah though it does then develop into $ab$-infra-zilch and the like

Semiclassical

What sound does a high energy theorist's parrot make?

SQUARK!

Slereah

Booooo

Semiclassical

14:28

I find that inordinately amusing and I'm okay with that.

Emilio Pisanty

> Pending the satisfactory physical interpretation of the new conserved quantities, economy of expression will be facilitated by assigning them convenient identifying names; the ten conserved extensive quantities $Z^{ij}$ defined by Equation (7) will hereby be collectively called the "zilch" of the electromagnetic field, and a particular one labeled by the indices $(i, j)$ will be referred to as the "$ij$-zilch" of the field.

actual quote from an actual physics paper

Semiclassical

haaaah

Emilio Pisanty

"I don't know what it is but it needs a name soooooo.... yeah, 'zilch' it is"

Slereah

IIRC very high derivatives of the position are called crack, snapple and pop

Emilio Pisanty

@Slereah indeed they are

Semiclassical

14:31

as far as SMBC comics with a moral go, this is probably my favorite one: smbc-comics.com/comic/2011-04-06

Slereah

arxiv.org/abs/gr-qc/0309109

Semiclassical

(which feels strangely pertinent...)

@EmilioPisanty anything new in saddle point land?

Emilio Pisanty

@Semiclassical not particularly

Semiclassical

the main thing I figured out lately is that I've got a periodic hamiltonian which is doubly degenerate...when I pick antiperiodic boundary conditions :S

Emilio Pisanty

I did meet an experimentalist yesterday and I'm quite confident that I've convinced him to carry out an experiment

so, on that front, =D

Semiclassical

14:34

oh nice

Slereah

@EmilioPisanty is that innuendo

Emilio Pisanty

@Slereah nope

I have discovered a new quantum number and we have strong theoretical evidence that it's conserved in (extreme, non-perturbative) nonlinear optics, so we're asking experimentalists to check

(I mean, not to toot my horn or anything)

Slereah

toot toot

Will you call it a splork

The splork number

Emilio Pisanty

@Slereah nope

I can share the acronym

TKAM

Semiclassical

@EmilioPisanty oh sweet

Emilio Pisanty

14:37

ah, weinersmith

just a tad late

Semiclassical

The main thing that’s neat about the double degeneracy in my case is that it raises the possibility that we’ve got instanton trajectories which interfere destructively

And that’d be pretty cool

Emilio Pisanty

gocomics.com/calvinandhobbes/1989/06/04

1989

bejeeesus

Semiclassical

I was about to say lol

Watterson did it first

Slereah

"What is not widely known is that not only was he adamantly opposed to Einstein's theory, after World War II he was actively working behind the scenes to undermine not just Einstein's physics, but Einstein's reputation as well."

oh no

Emilio Pisanty

there we go

bejeesus, gocomics tries hard to make that image inaccessible

@Semiclassical thirty years ago =|

btw have you seen the Hobbes & Bacon series?

pantsareoverrated.com/archive/2011/05/10/hobbes-and-bacon

plus a few others

Slereah

14:44

"The scientific reception of relativity in France"

Oh boy

Emilio Pisanty

Slereah

"With rare exceptions, teaching, textbooks, and university programs reflected the indifference toward the subject until the 1950s."

Ouch!

Semiclassical

@Slereah who is that about?

Slereah

Herbert Ives

Semiclassical

Hmm

I suppose a big difference between GR and QM is how immediately relevant they were from a technology perspective

Slereah

14:47

Well that was special relativity

which had immediate applications in nuclear physics

Semiclassical

Hmm, true

Yeah, I can understand a slow acceptance of GR more easily than a slow acceptance of SR

Slereah

SR took a while to get universally accepted

Semiclassical

sure, but 1950s?

Abcd

@JohnRennie I looked at the standard solution. My method was pretty much like it, but didn't get the right answer...

Slereah

Well, in France anyway

Semiclassical

14:51

Sure

It would be interesting to correlate that with what experiments French physicists were concerned with

John Rennie

Nature and nature's laws lay hid in night,
God said "Let Newton be" and all was light.
It did not last, the Devil howling "Ho!,
Let Einstein be!" restored the status quo.

Slereah

Apparently only Poincaré and Langevin really cared about SR when it first came around

other french physicists didn't really work on it

Semiclassical

And of course there’s also a difference between the reception by the French establishment vs younger physicists

Slereah

"As for the general conceptual framework, mechanics was all-powerful and affected a faultless orthodoxy that was spread by a system which taught physics as a rigid and solid body of doctrine from which all weak points had been eliminated or disposed of. Science was presented as a fully realized achievement, encased in certainty, organized around Newtonian categories and justified by a positivism that took on the colors of mechanism, or, in a lesser fashion, those of energetics."

Semiclassical

Planck’s line about science advancing one funeral at a time probably applies here

@Slereah What is the source for this?

Slereah

14:56

"The comparative reception of relativity"

a big book on relativity history

John Rennie

@Abcd we can have a look tomorrow if you want. I'm a bit busy for the rest of today.

Abcd

Okay, fine.

John Rennie

@Abcd Irodov problems are hard. Have you been recommended to study them? I would have guessed that you'd be better doing JEE question papers.

Abcd

@JohnRennie yes, my teacher recommended it because JEE can cross any level of difficulty anytime...it's unpredictable..

John Rennie

@Abcd well if you can do all the Irodov problems you should be in a good position, but don't be surprised if you find some of them very hard. What is the number of the problem you're stuck with? I'll Google around for a solution that shows the working.

Abcd

15:05

@JohnRennie Currently, I am stuck with one problem. I have already googled and found its solution...but I am worried about my method which appears to be absolutely correct but doesn't yield the right answer...

John Rennie

If you give me the number I might be able to find a solution that shows the working.

Abcd

Thermodynamics and Molecular physics question 41. (A heat conducting piston...)

Slereah

"Einstein gave this testimony: "Poincare was in general simply antagonistic [against the theory of relativity], and, for all his acuity, showed little understanding of the situation"."

John Rennie

@Abcd this for example

Emilio Pisanty

-1

A: What happens to a photon in a black hole?

Nothing in the material world has infinite mass, hence no material thing can be accelerated to light speed. It would require infinite energy to do so. This proves that there is a definitive ontological boundary between matter and light (mind). They do not belong to the same category of existence....

wow

Abcd

15:11

@JohnRennie Already seen.

Seen this too...

Anonymous

@Abcd If you want someone to check your solution (and where you went wrong), you need to write it down first. John can't read your mind...

Slereah

Apparently Langevin was pretty much the only one enthusiastic about SR in France

Abcd

@Blue Obviously, but he is busy that's why I can't tell him my method right now.

Most of the times I do that(sending my solution) in the Problem Solving room...

Slereah

15:28

"TSUTOMU KANEKO/Einstein's Impact on Japanese Intellectuals"

Oh boy

"On the business side, Kaizo's December 1922 special issue was sold out and reprinted, and Kaizosha's "Einstein Zenshu" (four volume-set), the first complete works of Einstein to be published in the world, sold an amazing 4,000 copies during and after the boom."

Some kind of Einstein anime?

Einstein No Zenshu

"Yokozeki later recalled that "When I asked him whom he was referring to, he replied Einstein. 1 thought he meant Eduard Bernstein (German social democrat)." "

Ouch!

" Yamamoto shot his pet question at this uncompromising philosopher. "Who are the three greatest people alive today?" Russell replied "First Einstein, then Lenin. There is nobody else." "

that article seems to be mostly about Einstein's trip to Japan

not so much about Japanese physicists

"the major physics journal (Zhurnal russkogo Jiziko-khimicheskogo obshchestva, chast' Jizikicheskaia, hereafter ZhRFKhO)."

Slereah

16:01

"In general, mathematicians in Russia were interested in STR and came out in support of it. Of course, mathematicians were constrained by the "chains" of generally accepted physical concepts to a lesser degree than physicists and mechanicians. Therefore, the radical conclusions of STR disturbed them less, and its mathematical order and the possibility of utilizing new geometric structures was more attractive to them. "

"Nevertheless, in 1922 an appeal "To German Physicists" was published in Zeitschrift fur Physik [115] with a call to help physicists in Russia overcome the informational famine and collect journals and offprints of the preceding years for them. "

Physics Meta

16:26

0

Q: Why was my answer on decoherence deleted?

My answer to this question was deleted. For anyone who can't see it, the answer was: I hope somebody will correct me if I'm wrong, but it seems that the simplest way to phrase the main objection is that decoherence doesn't even try to solve anything beyond "for all practical purposes." F...

discussion support

lılostafa

17:32

@JohnRennie I was using windows Remote Desktop to access a remote computer. A few hours ago some problem happened and I can't connect using RDP anymore (apparently some update is automatically installed which requires me to click "ok" somewhere, and this prevents the RDP session from connecting).

Fortunately I have a SSH server installed on that (windows) machine and currently can still connect and execute commands (in cmd) on it.

I'm trying to restart it but for some (unknown) reason, shutdown -r -f doesn't work neither!

Is there any other way to somehow restart that?

John Rennie

What error does does shutdown /r /t 0 give?

lılostafa

it just does nothing

and I have to Ctrl+C to get back

John Rennie

If it appears to complete successfully but nothing happens then that indicates the system is already in the process of shutting down.

You mean the command hangs?

lılostafa

yeah

John Rennie

I wonder what user account the SSH session is running as ...

lılostafa

17:37

administrator

John Rennie

you could try runas /user:administrator shutdown /r /t 0

lılostafa

Doesn't work :(

John Rennie

Hangs again?

lılostafa

Yeah

shutdown /r /t 0 always worked perfectly fine

Is there any indirect way (like killing a process) that breaks down everything and forces windows to restart? or something like this?

John Rennie

You could try killing lsass.exe. I think that's supposed to trigger a restart. I can try it on a test PC here if you want, before you go trying it ona live system.

lılostafa

17:47

I terminated lsass.exe but nothing's happened!!

John Rennie

Yes, on my test system taskkill /im lsass.exe /f forces a reboot

But it takes 60 seconds

Emilio Pisanty

@lılostafa your computer's still sassy, then?

lılostafa

@JohnRennie oh let's see what happenes

@EmilioPisanty It's Win7 service pack 1

Emilio Pisanty

or is lsass.exe just a thinly veiled reference by a German programmer to how Alsace should still be German?

John Rennie

I killed the process in an interactive session and immediately got a popup saying "your PC will restart in 1 minute"

Emilio Pisanty

17:48

@lılostafa to be clear, this is just me trying to troll

John Rennie

Local Security Authority Subsystem Service

Emilio Pisanty

@JohnRennie ooooh, "Authority" now, is it?

yeah, that sounds pretty sassy from the computer

John Rennie

Core module in Windows

It's been that way since the Windows NT 3.1 beta programme back in ... err ... early 90s some time.

lılostafa

It seems it hasn't worked as I'm still connected :)

(lsass.exe is killed and not running)

John Rennie

To be honest, if shutdown.exe hangs I suspect something in the kernel has hung.

lılostafa

17:52

:/

Is there a malware that I can install to force it to restart?

John Rennie

I suspect you may struggle to get the computer running again

lılostafa

@JohnRennie Physically restarting it should solve all the problems...

(if I had access to it)

John Rennie

rundll32.exe user.exe,ExitWindowsExec

rundll32.exe shell32.dll,SHExitWindowsEx 4

Grasping at straws now ...

lılostafa

Ohhh I just found someone at the lab!!!

Asked him to restart it. Let's see

John Rennie

Did he say what was on the screen?

lılostafa

17:59

He doesn't have an account

(and I can't give him mine:)

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