I restarted the elog with the script as it was not up when I tried to make a post. It was again unresponsive when I went to submit, but this time the script couldn't restart it. The log said it couldn't bind to 8080, which usually happens if the daemon is still running. I pkilled it, then reran the script, and it appears to be working.

Elog crashed / dormant for long time.  A look at the log file indicated that it was busy generating png thumbnails for pdf files.

Restarted at Wed Sep  7 20:41:13 PDT 2011

WTF?

Elog went nonreponsive. SSH'ed into nodus to run restart script. Elog came back ~15 minutes later.

Elog did not respond despite running the /cvs/cds/caltech/elog/start-elog.csh  script two times.  

It worked the after the third restart. 
 

Elog was hanging, restarted with the script.

Elog restart script killed the elog, but didn't restart it.  Restarted by hand.

I've noticed that it always takes running the script twice for it to actually work. I think there's something wrong with how it's doing it. I'll mess with it sometime the elog isn't getting much use.

Elog was not responding and was restarted.

Elog suspended 2 times for 1 hour. Too high frequency.

Restarted.

Elog was hanging. Restarted it with script.

Basically, elog hangs up by the visit of googlebot.

Googlebot repeatedly tries to obtain all (!) of entries by specifying  "page0" and "mode=full".
Elogd seems not to have the way to block an access from the specified IP.
We might be able to use http-proxy via apache. (c.f. http://midas.psi.ch/elog/adminguide.html#secure)

Or can we tweak the source of elod such that it does not accept "page0"?


GET /40m/page0?mode=full&new_entries=1 HTTP/1.1
Host: 131.215.115.52:8080
Connection: Keep-alive
Accept: */*
From: googlebot(at)googlebot.com
User-Agent: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
Accept-Encoding: gzip,deflate

 There are much more simple ways to prevent page indexing by googlebot: http://www.google.com/support/webmasters/bin/answer.py?answer=156449

However, I really think that's a less-than-idea solution to get around the actual problem which is that the elog software is a total piece of crap.  If google does not index the log then it won't appear in google search results.

But if there is one url that when requested causes the elog to crash then maybe it's a better solution to cut of just that url.

- elogd itself is a sort of web server which has no freedom to put our own file, we can not put robots.txt

- If we include elog using proxy in the usual web tree of Apache, we can put robots.txt at the root.

- So far, if we prevent "page0" browse by google, we will be saved for a while.

- It seems that the indexing is set to be refused by the following meta tags. But it does not prohibit googlebot to use "page0" URL, of course.

<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">

 with script.

Gave the elog its afternoon / tea-time reboot, since it was hanging yet again.

Tried the script 3 times and it didn't come back. Pkill'd and then scripted. That worked.

I modified elogd.c as shown below in order not to allow to display all of the entries at once by specifying page number "0".

After this modification, elog seems to have survived 66 times of attacks by googlebots.

==============================

rossa:src>pwd
/cvs/cds/caltech/elog/elog-2.8.0/src

rossa:src>diff elogd.c_orig elogd.c
19912a19913,19917
>
>    /* KA */
>    if (page_n<1)
>      page_n = 1;
>


On the plus side, it was the first time I've had to do it in a while..

The elog was not responding. I attempted to restart it by running .../start-elog.csh, but this didn't work (even after the usual ~2 times it needs).

Somehow pkill did not kill the daemon, so I kill -9'd it and that did the trick. I ran the start script once more and it came back online.

 Aim: to scan the cavitymodes of IMC

The circuit used: 

 Attachment4

Results obtained:

Attachment 1,2,3

I deleted a bunch of useless categories from the 40m elogd.cfg file. IF you find your category has been deleted, you can now learn how to categorize yourself into the existing categories. ELOG restarted and log file zeroed.

 The ELOG was frozen, with this in the .log file:   

GET /40m/?id=1279&select=1&rsort=Type HTTP/1.1

Cache-Control: no-cache

Connection: Keep-Alive

Pragma: no-cache

Accept: */*

Accept-Encoding: gzip, deflate

From: bingbot(at)microsoft.com

Host: nodus.ligo.caltech.edu

User-Agent: Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)

  (hopefully there's a way to hide from the Bing Bot like we did from the Google bot)

ELOG is back up and running after last Friday's disk-crash-a-thon. SVN is still a work in progress. Jenne and I are now restarting computers and such.

 Plans for the Week:

• Phase and noise characterization of the UFC RF Frequency Counter.
•  Characterization of the temperature actuator.

Progress and Problems Faced:

• Since past two days, I have been trying to measure the phase difference between the input and output signals of the FC using a 16 bit ADC ADS1115 (for input phase measurement) on Raspberry Pi(RPI).For that I have assembled a Circuit on a breadboard( Details will be mentioned in my next eLog). 
• The interfacing and the codes seem to be alright but the RPI is not able to detect the address of the ADC chip. I will try to debug the issue as soon as possible and try to take data through the Pi so that I can have both delay and noise introduced by the FC.
• Now since the minimum sampling time of the FC has been brought down to 0.1s, I will test how accurately the FC is writing values every 0.1 s for a modulating input.
• The output data of the FC will be fitted into the input and the order of accuracy will be presented.Also the gain plots will be plotted at higher frequencies like 50 MHz, 100 MHz, 500 MHz and 1000 MHz using the network analyzer.

Work Inside the Lab:

• On Friday Morning I will  go inside the  lab with Manasa to make measurements from the NPRO to characterize its response to the temperature.
• I will be in the lab in the morning session(9 am- 1 pm) and make the required measurements. I will then analyze the data and by the end of the week will finish characterization of the FC and temperature actuator.
• For the rest of the time in this week, I'll be on my desk and will not be entering  the lab.

Electronics Required:

• I will require the network analyzer on Wednesday and Thursday to make measurements at higher frequencies(30 MHz <F<1000 MHz) from the R PI.

Goal- By the end of the week:

• To characterize both the FC and the NPRO that would go into the FOL-PID loop.
• The FC will be ready to replace the network analyzers that are currently being used in the 40m.

 I was asked to calculate the lenses that we need in order to obtained a Gouy phase close to 90 degrees between the two mirrors that are in the Xend green. Yesterday, I measured the distances between the mirrors, and the distance between the mirror relative to the cavity as illustrate in the image attached below. I looked in to the 40m elog and Manasa did the last update on the length of the cavity. She measured 37.7 + 0.05m. The waist size of the beam that was measured by Annalisa in ID 8637 after the Faraday was w0=2.943e-5m @ -0.039m. I calculated the waist size inside the cavity, and I found a waist of w0=2.2 mm. My plan this week is to keep working in the calculation and finish all the calculation this week so that next week I can go inside and place the lenses. 

Yesterday elog was excruciatingly slow, and bingbot was the culprit. It was slurping down elog entries and attachments so fast that it brought nodus to its knees. So I created a robots.txt file disallowing all bots, and placed it in the elog's scripts directory (which gets served at the top level). Today the log feels a little snappier -- there's now much less bot traffic to compete with when using it.

We might be able to let selected bots back in with a crawl rate limit, if anyone misses searching the elog on bing.

Oh, this is cool! Thanks!
I could not figure out how to place robot.txt as it was not so obvious how elogd handles the files in the "logfile" directory.

I tried to find my own entry and faced with a strange behavior of the elog.

The search button invoked the following link and no real search has been done:

http://nodus.ligo.caltech.edu:8080/40m/?mode=summvry&reverse=0&reverse=1&npp=50&m&y&Authorthor=Koji

Summvry? Authorthor?

If I ran the following link, it returned correct search. So something must be wrong.

http://nodus.ligo.caltech.edu:8080/40m/?mode=summary&npp=50&Author=Koji

In order to fix ELOG search, I have started running ELOG v2.9.2 on Nodus.

Sadly, due to changes in the software, we can no longer use one global write password. Instead, we must now operate with registered users.

Based on recent elog users, I'll be creating user accounts with the following names, using the same old ELOG write password. (These will be valid across all logbooks)

• ericq
• rana
• koji
• diego
• jenne
• manasa
• Steve
• Kate
• Zach
• Evan
• Aidan
• Chris
• Dmass
• nicolas
• Gabriele
• xiaoyue

All of these users will be "Admins" as well, meaning they can add new users and change settings, using the "Config" link.

Let me know if I neglected to add someone, and sorry for the inconvenience.

RXA: What Eric means to say, is that "upgrading" from Solaris to Linux broke the search and made us get a new elog software that;s worse than what we had.

 So, despite having registered users, it turns out that the "Author" field is still open for editing when making posts. I.e. we don't really need to make new accounts for everyone. 

Thus, I've made a user named "elog" with the old write password that can write to all ELOGs. 

(Also, I've added a user called "jamie")

No elog response from outside and no elogd process on nodus, so I restarted it using 'start-elog.csh'.

If it all possible, don't use links to your home directory. Its not robust. It would be like if you clicked on your Google Music and it told you to ask me to sing that song to you. Imagine that on auto-repeat next time your fancy-bone itches.

Elogd have been restarted several times today because it died everytime I submit something.
Here is the copy of the log.

"Why does the word wrapping not work in our browsers with ELOG?" I sometimes wonder. Some of the elogs are fine, but often the 40m one has the text run off the page.

I found that this is due to people uploading HUGE images. If you need to do this, just use the shrink feature in the elog compose window so that we only have to see the thumbnail at first. Otherwise your 12 MP images will make it hard to read everyone else's entries.

(keerthana, gautam, jon)

In the morning, Jon gave me an overview of the Auxiliary laser system which we are planning to setup. Based on the diagram he uploaded in the elog, I have made the MEDM diagram for controlling and displaying the parameters. Here the parameters which we will be controlling are temperature (in terms of voltage), oscilator frequency ( with the help of IFR 2023B), the frequency offset and the PID controls. The display includes the beat frequency, error signal voltage, control voltage and a switch to give feed back to the AUX laser. As the frequency counter is not connected at the moment, I haven't included its channel number in it. The screenshot of the diagram is attached with this. I am also considering to give a PID feedback to the slow control from the AUX feedback signal. The screen can be accessed from the PSL dropdown menu in sitemap.

I think this table will help us to fix the scanning range of the Marconi frequency. This will also help in predicting the position of the resonance peak corresponding to the injected frequency.

f_diff = f_m ±80 MHz ;                     f_diff = N*FSR_y ;              FSR_y = 3.893 MHz.

The values obtained from both analytical and finesse solution is given in the above table along with the corresponding percentage errors.finesse1.pdf

The parameters used for this calculation are listed below.

Parameter	Value
length of the cavity (L)	38.5 m
Wavelength of the laser beam ()	1064 nm
Radius of curvature of ITM (R1)
Radius of curvature of ETM (R2)	58 m

The cavity scan data obtained from Finesse is also attached here.

Hmm? What is the definition of the percentage error? I don't obtain these numbers from the given values.
And how was the finesse value obtained from the simulation result? Then what is the frequency resolution used in Finesse simulation?

The percentage error which I found out =[(analytical value - finesse value)/analytical value]*100

But inorder to find the finesse value, I just used curser to get the central frequency of each peak and by substracting one from the other I found TMS and FSR.

The resolution was 6500 Hz. Thus, it seems that this method is not actually reliable. I am trying to find the central frequency of each mode with the help of lorentzian fits. I am attaching a fit which I did today. I have plotted its residual graph also.

I am uploading 4 python scripts to the github.

1. Analytical Solution

2. Finesse model- cavity scan

3. Finesse model- fitting

4. Finesse model- residual

fitting_1.pdf

> The percentage error which I found out =[(analytical value - finesse value)/analytical value]*100

Yes, I this does not give us 0.70%

(3.893408 - 3.8863685)/3.893408 *100 = 0.18%

But any way, go for the fitting.

Oopss !! I made a mistake while taking the values from my notes. Sorry.

I have modified the code for frequency scanning and have made it completely command line enabled. The code is written in python. It is saved in the name "frequency_scanning_argparse.py". I have uploaded it to the Mode-Spectroscopy Github repository.

Inorder to use this code there are two ways.

1. We can mention the ' frequency' on which marconi need to work. Then it will change the marconi frequency to that perticular value.

eg: Type in the terminal as follows for changing the marconi frequency to 59 Mhz.

python frequency_scanning_argparse.py 59e6

2. Inorder to give a scan to the marconi frequency, provide the 'start frequency', 'end frequency' and the 'number of points' in between. This will be more conveniant when we want to run the scan in different ranges.

eg: Type in the terminal as follows for a start frequency of 59 Mhz, end frequency of 62MHz and number of points in between equal to 1000.

python frequency_scanning_argparse.py 59e6 62e6 1000

In both cases the code will show you the frequency of the marconi before we run this code and it will change the marconi frequency to the desired frequency.

(Jon, Keerthana, Sandrine)

We tried to align the AUX and PSL laser yesterday. We collected the data from the spectrum analyser for the Y-ARM reflection and also for the Y-ARM transmission from the ETM mirror. I am attaching the plots here.

• N/S ARM FL.
• N/S ARM INC.

These two lights inside the 40m-lab are not working.

(Analisa, Sandrine, Keerthana)

Today Annalisa helped us to understand the new set up used to make the frequency scans of the AUX laser. While tracking the cables it seemed that there were quite a lot of cables near the mixer. So we have reconnected one of the splitter which was splitting the RF out put signal from the Agilent and have placed it just near the Agilent itself. A picture of the changed setup is provided below. The splitter divides the signal into two components. One goes to the LO port of the mixer and the other goes to the R port of the Agilent. We have tried locking the PLL after the change and it works fine. We are trying to make a diagram of the setup now, which we will upload shortly.

I tried to compare the cavity scan data we get from the Finesse simulation and that we expect from the Analytical solution. The diagram of the cavity I defined in Finesse is given below along with the values of different quantities I used. For the analytical solution I have used two different equations and they are listed below.

Analytical 1 - Blue Graph

Analytical 2 - Red Graph

The graph obtained from both these solutions completely matches with each other.

Finesse Solution

The cavity which I defined in Finesse is shown below. The solution from Finesse and the Analytical solution also matches with each other. Another plot is made by taking the difference between Finesse solution and Analytical solution. The difference seems to be of the order of .

The Difference plot is also attached below.

All of our wikis (except the 40m one which unfortunately got turned into ligo.org mess) use DokuWiki. This now has an auto-upgrade feature through the Admin web interface.

I tried this recently and it fails with this message:

DokuWiki 2018-04-22a "Greebo" is available for download.
 You're currently running DokuWiki Release 2017-02-19e "Frusterick Manners".
 New DokuWiki releases need at least PHP 5.6, but you're running 5.4.16. You should upgrade your PHP version before upgrading!

So we'll have to wait until SL7 (which is what NODUS is running).

I DID do a 'yum upgrade' which updated all the packages. I also installed yum-cron so that the RPM listings get updated daily. But sadly, SL7 only has PHP 5.4.16 (which is a June 2013 release):

> Package php-5.4.16-43.el7_4.1.x86_64 already installed and latest version