"Back" button behavior in the VM

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bmendez
Stardust@home Team
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"Back" button behavior in the VM

Post by bmendez »

Hi All,

We have discovered that a change has occured recently in the behavior of the VM. When you are searching and push the "back" button on your browser you used to see the previous movie with an error message ("warning you have reached this page by an unusual route..."). If you made any clicks on the movie, after arriving at the page this way, they would not count. This was useful to allow people to go back and review movies to take note of their ID number, etc.

Now, however, we are seeing a whole host of behaviors when using the "Back" button. Some people still see the message as before. But others will see the previous movie with no error message. Others report finding that a completely different movie loads.

We'd like to understand what has happened, as we have made no changes to the VM.

It's possible that it is an issue having to do with with an update to web browsers and how they are handling caching. It may also be an issue with how our webserver is handling caching.

We'd like to ask for you to let us know what you are experiencing. Please help us figure out this new behavior by trying to use the "Back" on your web browser while searching and reporting to us your experiences.

Do you see the "unusual route" error message?
Do you see the same movie that you were previously on, or a new movie?
What browser and version are you using?
What are the browser's cache settings?
Is there a difference in the behavior if the previous movie was Real or a Calibration movie?
Is there a difference in the behavior that appears to depend on the length of time since you last viewed the previous movie? Please describe that dependency.

Thanks to all of you. Hopefully we can figure this out soon and return the behavior of the VM to something famliar and helpful.

-Bryan
"I am made from the dust of the stars, and the oceans flow in my veins"
- RUSH

fflo
Posts: 63
Joined: Tue Aug 08, 2006 7:37 am
Location: Eindhoven, Netherlands

Re: "Back" button behavior in the VM

Post by fflo »

bmendez wrote:Hi All,

..................................................

We'd like to ask for you to let us know what you are experiencing. .............................................

Do you see the "unusual route" error message?
Do you see the same movie that you were previously on, or a new movie?
What browser and version are you using?
What are the browser's cache settings?
Is there a difference in the behavior if the previous movie was Real or a Calibration movie?
Is there a difference in the behavior that appears to depend on the length of time since you last viewed the previous movie? Please describe that dependency.

.....................
-Bryan
My observation as of yesterday:
- I had one exception to the normal behaviour: My first movie after starting the Virtual Microscope yesterday was a Calibration movie and when I went "Back" for checking after clicking (correctly), I got the "new behaviour", i.e.: no "unusual route" error message and the same movie I was previously on.
I did not click again, instead used the "Bad Focus" button (the first time to be save!) and went on.
The CM was counted correctly.
After that I got several times the "unusual route" error message and the same movie I was previously on, wether it was Real or a Calibration
movie.
- I am using Netscape browser, version 8.1.3.0
P.S.: I didn't try to figure out it's cache settings.

Hoping that I could help a little, I am wishing happy days, a Happy New Year and all the best for 2008,
to you, the crew and the dusting community

fflo
________________________-

from dust we come - for dust we search - to dust we go

laserphil
Posts: 81
Joined: Sat Dec 02, 2006 8:28 pm
Location: Sydney Australia

Re: "Back" button behavior in the VM

Post by laserphil »

I also checked this operation today with both CM and real movies. On all occasions it returned the previous movie with the standard "you have reached........".

I am using both Netscape 7.2 and Firefox browsers. Both behaved as above.
Likewise I did not check cache settings.

I would like to add my seasons greetings to the Stardust team and to all my Stardust friends. May you all have a safe, happy Christmas and New Year and find those illusive tracks!!!

I think I'm starting to wear the letters off the "NO TRACK" button!

Laserphil

jelfving
Posts: 12
Joined: Tue Aug 08, 2006 2:34 pm

Post by jelfving »

Hi!

I just viewed 34 movies, pressing the browser's (the VM doesn't have a Back-button, does it?) Back-button each time after the "verdict" regarding the movie I just viewed had come. Each and every time I was served another movie than the one I just had evaluated, without any claim regarding "unusual route". I continued by evaluating the movie I arrived at by the Back-button. As it happened, there were 2 CM's among them (one with, the other without a track), 25 No Track's and five Bad focuses. I viewed the first 23 movies in rapid sequence, and in the last 11 cases I waited about 0.5 min before clicking the Back-button: no difference. In the last 11 cases, I also checked that the movie loaded via the Back-button was not the same as the one displayed when I hit that button.

I have Windows XP (service pack 2), Mozilla Firefox 2.0.0.11, and as for cache settings, I'm not so sure where to look and what to look for, but in the browser's "options" I read that up to 50 MB are reserved for the cache, that the browser remembers pages visited during the last three days, and that it accepts cookies.

Merry Christmas to all Stardusters, and especially to the Dustmods!

jelfving
Posts: 12
Joined: Tue Aug 08, 2006 2:34 pm

Post by jelfving »

Sorry, there were seven (not five) Bad Focuses!

jelfving
Posts: 12
Joined: Tue Aug 08, 2006 2:34 pm

Post by jelfving »

I continued dusting without especially addressing the Back Button Broblem, but nevertheless tried every now and then. The behavior of the button was now erratic: sometimes it gave a new movie, sometimes the old one, accompanied dutifully by the "unusual route" comment. I couldn't discern any method in the madness, but the cases were relatively few.

bmendez
Stardust@home Team
Stardust@home Team
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Joined: Wed Apr 19, 2006 11:28 am
Location: UC Berkeley Space Sciences Lab
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Post by bmendez »

Thank you so far for your reports. They will definitely be helpful in determining what is causing this change in behavior. Please keep them coming.

One other piece of information that may be helpful for us as well would be your operating system and its version.

Cache settings are difficult to find in many browsers. In IE, look in the Internet Options (under Tools). Under the General tab in the middle of the box are the Temporary Internet File options. Those would be your cache settings.

Security settings might also be a factor here, so if you can tells us about those as well. It could be helpful.

Thanks again to all.

Have a happy holiday season!
-Bryan
"I am made from the dust of the stars, and the oceans flow in my veins"
- RUSH

elainekeefe
Posts: 190
Joined: Fri Aug 04, 2006 4:38 am
Location: Massachusetts, USA

Post by elainekeefe »

Hi Bryan. I have Windows XP, Verizon Fiber Optic IS, and run MSN Explorer as a browser. Settings are 100/automatic/0. I have no problems at all with the back and forward buttons except for the very first movie. When I try to go back to that, I get a new movie. I just did 10, including 2 bad focus and 3 negative cm's. On each movie except the first I was able to go back and forward, getting the typical "unusual route" message. I also have no trouble backing up when I leave to go to "My Events." Using the back button I go back to the same movie I left. Hope this helps.

auggienanz
Posts: 1
Joined: Sat Jan 05, 2008 3:17 pm

Post by auggienanz »

I am using Windows Vista, and the back button in Safari displays the unusual route message. However, Opera 9 does not display the unusual route message.

Hope this helps,
Auggie Nanz

jsmaje
Posts: 616
Joined: Tue Aug 15, 2006 8:39 am
Location: Manchester UK

Post by jsmaje »

Bryan,
I've noticed some reproducible patterns regarding this problem, which I've tried to illustrate in the flow diagrams below:

Image

Diag.(A): This shows what fflo & elainekeefe report always happens on clicking back from the second movie to be viewed, i.e. a completely new movie instead of the first. This behaviour continues as long as one cares to access new movies in such a way.

Diag.(B): If one views a few more movies before clicking back, previous movies (showing the 'unusual route' message) will be correctly shown until one reaches what should have been the first seen, when a new one appears yet again.
Clicking forward at any point before reaching this stage produces normal behaviour. On going forward from an unexpected new movie, however, all previously seen movies bear the 'unusual route' message, preventing the last (as yet unjudged) movie from being judged.

Diag.(C): Clicking 'go to a new movie' at the above stage of course produces a new movie, but this then also becomes irretrievable on clicking back in the same way as the very first.

Diag.(D): Judging a correctly-presented (as yet unjudged) previous movie leads to normal behaviour, unless one clicks all the way back to the first movie position again.
Clicking 'go to a new movie' instead of using the forward button when at one already judged, however, results in the same problem as in (C).

Diag.(E): The above behaviours in combination can lead to seemingly bizarre results, as jelfving and others have experienced, erroneous new movies cropping up every few or even alternate movies, depending on one's trajectory through the VM.

The consistent feature seems to be that 'Position 1' is somehow labelled at the client or server end as 'Get a new movie' regardless of what was previously there, the same happening at whatever position one may arrive at after going to a new movie from the 'unusual route' screen. As a consequence this also incorrectly leads to all previously-seen movies being treated as having been judged.

I've tested these trajectories several times in the two browsers I use from different stables (IE7 & Netscape 7.2) with the same results, suggesting that the problem isn't a random one or exclusive to browser type.
My OS is Windows XP (v.5.1, SP2), with a 250MB cache set to Automatic for new pages. Trying 'Never' for the latter makes no difference, nor have I noticed any dependence on timing, type of movie, or the way I may have judged them. Fortunately your scoring seems unaffected whatever movie is on-screen.

Hope this helps, particularly if others can reproduce these patterns (I recommend noting down each movie number rather than trying to recall their appearance).

John

Wolter
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Location: Enkhuizen, the Netherlands

Post by Wolter »

I have tested John's scenarios A, C and D and i get the exact same behaviour.

I am using Firefox 2.0.0.11 on XP Pro - SP2
I have a direct internet connection and use a 50 MB cache
Just dusting... Image

Nikita
DustMod
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Location: Indiana, USA

Post by Nikita »

Wow! Amazing job John!

You really put some time into that!

I hope you helped solve the problem!
From dust we come

bmendez
Stardust@home Team
Stardust@home Team
Posts: 530
Joined: Wed Apr 19, 2006 11:28 am
Location: UC Berkeley Space Sciences Lab
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Post by bmendez »

Thanks John!

That is a huge help. I'm at a conference in Austin this week, but I will make sure Will and Robert get your analysis today at our usual team meeting.

-Bryan
"I am made from the dust of the stars, and the oceans flow in my veins"
- RUSH

jsmaje
Posts: 616
Joined: Tue Aug 15, 2006 8:39 am
Location: Manchester UK

Post by jsmaje »

bmendez wrote:Thanks John! That is a huge help. I'm at a conference in Austin this week, but I will make sure Will and Robert get your analysis today at our usual team meeting. -Bryan
You're welcome, but why is this problem still uncorrected after several weeks of being alerted to the issue?

If it's simply a matter of Will's and Robert's limited time, that's one thing.
If, though, it's about how much they demand you pay them, then let me be first to offer them $50 - each!!! John :lol:

Will
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Post by Will »

Hi John:
This is on my plate, it isn't Robert's fault. Sorry, there just haven't been enough hours in the day this month! :( Your analysis was/is very helpful and sparked some ideas. But I need to set aside a day to dig into it.
Best wishes,
Will

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