Wednesday, January 11, 2012

Rails Backbone.js

Gettting Started with  Rails

Tutorial Book

CloudEdit: A Backbone.js Tutorial with Rails 
Backbone.js really introduces a new kind of data flow for Rails apps. Instead of data flowing like this:Rails Model => Rails Controller => Rails View

It now flows like this:
Rails Model => Rails Controller => Backbone Model => Backbone Controller => Backbone View
What I've found is that overall, Backbone.js makes it really simple to create highly responsive Javascript heavy applications.

Monday, December 26, 2011

From Authority

Y Combinator List:

When Adam D'Angelo says "partition your data at the application level", what exactly does he mean
  - FriendFeed did a pretty good writeup on theirs here (though there are some other differences between their system and what I'm advocating, the system for partitioning and maintaining secondary indexes fits right in):
 - see also Memcache lessons from Reddit    Reddit lessons
Memcache  Implementation lessons from different companies  - asr: a Ton of companies are using memcache with Schema Less Databse ...
mySQL , Memcache at NetLog  -- SchemaLess DB ..,,

Memcached and "N" things you can do with it – Part 1

Why Quora Use MYSQL not  MongDB
 - We use Thrift to communicate between different backend systems.
- Our main webserver is paste (the default for Pylons) with nginx and HAProxy in front of it.  For our Comet server, we use Tornado.
- We mostly use Amazon EC2 and S3 for hosting.
- Our data store is mostly MySQL + memcached right now, plus two services written in C++.
 HTTP Servers, Proxies , and Caching ...

Nginx's load balancing features are less advanced than haproxy's but it can do a lot more things (eg: compression, caching), which explains why they are very commonly found together. I strongly recommend it to whoever needs a fast, reliable and flexible web server !  -- features ..

January 2012 Web Server Survey - NginX gained
WordPress moved to NginX 8-9K connections/sec 
8-9k requests/second  and about 1.2Gbit/sec through a few Nginx instances and have plenty of room to grow!

Varnish  - Varnish Cache is a web application accelerator also known as a caching HTTP reverse proxy. You install it in front of any server that speaks HTTP and configure it to cache the contents. Varnish Cache is really, really fast. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture.

HAProxy is a freevery fast and reliable solution offering high availabilityload balancing, and proxying for TCP and HTTP-based applications. It is particularly suited for web sites crawling under very high loads while needing persistence or Layer7 processing. Supporting tens of thousands of connections is clearly realistic with todays hardware
HAProxy used by Yelp , same thing used by  Quora 
1/ Development effort

- 8 member team worked 9 months: We had two developers, two designers / front-end developers, two developer interns, and help from our sys admins, support team, and founders Joel and Michael

I would say a rough estimate of around 3,300 person-hours went into Trello.
- Trello took nine months to develop from concept to launch. 
2/ What language is Trello written in? Mostly Coffeescript.
3/ Launching Trello : PR , 9 months effort , user visits

posterous Tech Stack
To interact with the API, we've used some awesome front-end technologies. Among all the awesome stuff we've been able to work with while creating Spaces, the most notable are  BackboneCoffeeScriptHaml.jsSass, and Compass. Today I will touch on our use ofBackbone.

 who: LinkedIn’s mobile development lead Kiran Prasad
 -The app is two to 10 times faster on the client side than its predecessor, and on the server side, it’s using a fraction of the resources, thanks to a switch from Ruby on Rails to Node.js
-They went from running 15 servers with 15 instances (virtual servers) on each physical machine, to just four instances that can handle double the traffic. 
Also, the app is insanely lightweight. “If you take our entire app and you combine all the framework pieces and zip it, it’s under 50K,” said Prasad.
-On the server side, our entire mobile software stack is completely built in Node,” said Prasad. “We use a ton of technologies at LinkedIn, but for the mobile server piece

Choosing the Best Architecture

Nick Kallen (@nk), twitter engineer:
  • "All engineering solutions are transient
  • Nothing's perfect but some solutions are good enough for a while
  • Scalability solutions aren't magic. They involve partitioning, indexing, and replication
  • All data for real-time queries MUST be in memory. Disk is for writes only.
  • Some problems can be solved with pre-computation, but a lot can't
  • Exploit locality where possible"

Big Data in Real-Time at Twitter:
Instagram architecture:
Facebook: and

Groupon architecture:

How I Designed in 1 Hour
So despite the late hour, I said I didn’t mind helping, got the PSD, and hopped into Photoshop for a few quick touch ups.
Using a standard font often means you’re missing an opportunity to make a statement and create a connection with the user. This is why I choseMuseo Slab, a strong yet playful font that I knew was available on Typekit as a webfont.
asr: we need this kind of help for  showing VCs, after developing  a simple UI ... b) it seems they do first in Photoshop and convert to HTML 

site has Great UI , seems  Photoshop driven ..

Why You Should Use Analytics

The fundamental reason you want to use analytics is because
-  it lets you know how your customers interact with your site and
-  that this drives decisionmakingabout your site design, future business directions, and the like.

Layout UX Interaction / good Layouts

Main page Layout
This Plurk UI seems good , small fonts ,   good Hide button  for language
-This Left menu Dim seems is a UI standard , I saw it many places .

Good UX interaction when selected item: It is close to ( Trello Cards ... ) , may be we use this one .
  - good tabs , smooth transition from  '4 col grid to 2 col grid'

FAQ Layout :
ODesk faq:   simple and elegant with  'top'

Site Templates
Site Templates:  , good Site Template ( with no flicker Documentation ) ,  show/Hide options ( like )
 - Horizantal/vertical Tab pages, Nice options box  , Mega Menus ..

BLOG templates:
 - 2 Level Tabs:  , good for easy access of information .
-  Amix: good font and nice charts ( small ) to merge with text ..

Ranking / Personalization

How Hacker News ranking algorithm works

The above mentioned categories are just a few of the many that you can found on YouTube. Additional categories include 
- arts and animation, 
- autos and vehicles, 
- news and blogs, 
- people, sports, and
-  science and technology.

Sunday, December 25, 2011

Interactive User Experience / UX

How I Designed in 1 Hour

So despite the late hour, I said I didn’t mind helping, got the PSD, and hopped into Photoshop for a few quick touch ups.
Using a standard font often means you’re missing an opportunity to make a statement and create a connection with the user. This is why I choseMuseo Slab, a strong yet playful font that I knew was available on Typekit as a webfont.
asr: we need this kind of help for  showing VCs, after developing  a simple UI ... b) it seems they do first in Photoshop and convert to HTML 
- asr : we can ask for help for our HTML5 based elearn character , first to develop  character animation in  PhotoShop ( good site said by above sachagreif )

self: How can we further improve this great tutorial of Python, where people can use it like CAcademy ..

Dive Into Python  - Python from novice to pro

In this Python tutorial , autors took good approach of numbering and explanation for it .
 - This can be further improved with coffee script document style , one shown here . This layout so easy to Read. Here is  the actual DOCument app

- You can also make this official python guide into  for easy redability and integratioin into Python shell or CAcacdemy

- you can do this Python Reference or any other lang. reference  -- seems good one ..

Saturday, December 24, 2011

Concept mastery

1/ Introducing Fraction 

 These are the first 2 google searches  for 'Adding fractions '
method 1: Fractions:  - good sequence of topics to all the way  'Add/Subtract' fractions , notice steps given for division , we can use similar steps with audio Cacademy style .. ( do with HTML5 shapes and audio )
       - At the end Laws of Arthamatic is good , stating 'Commutative' , associative laws

Method 2: Sequence of Objectives for Adding and Subtracting Fractions
  - if fractions are taught correctly, they are fun and easy to learn. Most texts move children too quickly into adding with unlike denominators
  - Nice 50 sequence steps 

method 3:
  ( here no easy method for finding LCM )

method 4:  easy LCM  , what we taught to gitu ( youtube users 300k , use this kind of numbers for our )

1) Diagnostic Test  ( I would call this as  PreTest or Pre-Requisite )
Give a speed test on at least the multiplication facts. It would be good to give a speed test on each of the basic functions sometime during the week.

  Purpose: Fractions are used for many, many things. They are commonly used in recipes for cooking: 1/2 cup, 1/4 tsp., etc. Carpenters use fractions in measuring and cutting boards. We can use fractions with time: half an hour, a quarter past two.

Pretest , PreRequisite: There will be check boxes as kid has to complete each one  ( and proficient 10 correct in a row like Khanacadmy ... ? ) before going into next one ..
 for fraction  Addition, Subtraction  the PreTest is
 a) multiplication facts :  3x4 = 12
 b) split multiplication :   12 ->  3 x 4    ;   12 ->  2 x 6
 b) equivalent fractions :  1/2 is same as 2/4

2) Concept of Fractions , Naming fractions:
   Anticipatory Set:  ( good plan ) , wish collages have this thing ...
Check for Understanding: 

Tuesday, December 20, 2011

Content funding

 Audery Watters:

funded:  funded compaines in the  Education/Learning/ELearning Space

1)  -  interactive Code learning
   - YC S11 (Aug 11 launch )  , Series A 2.5MM (USV  Fred lead with Chris dixon , Naval Ravikant , Ron Conway )

3)  - Pooja  IIT Kanpur 2001  CS grad ,  Oracle , Kosmix , Facebook
    - Started  late 2009 , raised 400K in 2010  (Ex-Goole ) , Series A  1.5MM

2) - Tech tutorials with Video ( $25/month) , NY based founders ..
 Raised $600K (Hoffman ... )

4) Facebook app for home work colloboraton : funded by Gates foundation ...( I noted , but need to find it )

12 Major Foundations Commit $500 Million to Education Innovation in Concert with U.S. Education Department's $650 Million "Investing In Innovation" Fund
20 Ways Siri May Forever Change Education

 Audery Watters:  - Peter Norvig , Paul graham are on List ... so seems good profie people for network ...
 - varma ( their VC network )
 - sridhar
 - techcrunch/gaigaOm and other editors
 -  middle men ...  -- Mega List ...
codeAcademy funed USV  - Jq-console bid .. only 2 days...  -- This works ..  -- her is enquiry , may be we can ask in scriptlance ...

"Coding is going to be the literacy of the 21st Century, and we think we have the easiest way to do it," says co-founder Zach Sims.
After working with a variety of startups in business development roles, Sims, who is 21, dropped out of Columbia to focus on his own venture. He teamed with Ryan Bubinski, 22, who graduated from Columbia with a degree in computer science and biophysics -- and, more importantly, an extensive knowledge of programming.
-  Launched in June, the New York-based site has already attracted $2.5 million in a funding round led by Union Square Ventures and is a graduate of Y Combinator, one of Silicon Valley's most closely watched incubators.
-Lessons  Right now, there are still only two of us working on the company.” ( they did not hire 2 months after funding)
- New York based ( good not our local ,  it shows  Tech savvy Vally lost opertunity to New York  Liberal arts ..)
- Sim is dropped out , non-tech worked in biz dev ... Ryan is tech guy ..
- It seems Sim had pain for learning programming  ( since drop out ) .. so Startup came from PAIN ...
- USV Fred is smart who is Lead for this round, got  SV angle, FoundersFund, NAVAL .. got main guys in so that no Vally competition .

asr: Stats
- that is lots of web sites 13,370  ,   
-  venturehack says 20 user limit for video , if we have audio we may have less … limit or we can pay audio … let us see  )
- Yo Google, Skype – what about the web?We don’t feel that the video chat itself is the destination.
- We think of it as a facilitator of real human interaction around whatever else you want to be doing, discussing or watching, wherever you are.
- Being able to take any website, application, piece of content, in fact any object on the web that can be the focus of shared interest – and use that object to gather people together and allow them to communicate face to face, there and then, in context – that is where we see huge opportunity.

The OpenTok concept is thus an inversion of the usual video chat paradigm, where the video stream itself is front-and-center and users have nothing to focus on but each other. 
- “Content fuels conversation,” says Small. ( asr: we are having content ... )
 -“The ‘aha’ moment for us came when we noticed that people who watch YouTube movies together hang out for an hour or more. They’re half talking, half watching, half chilling. So we said, ‘Why are we spending time trying to figure out how to fit the Web inside our service, instead of taking our service and fitting it to the Web.’”

People are always invited to go to silo destination sites for video conferencing, and that’s just not the real world,” said Micky O’Brien, vice president of marketing for TokBox. “They want to engage with others around an activity, and they want to do it immediately.”

Once video is captured from a web-enabled camera, it’s sent over to the TokBox servers and compressed. It’s then streamed to people viewing a website with Flash. While the streaming technology is handled by Flash for now, the APIs are already prepared in a way that TokBox can shift over to HTML5 once the technology is ready, O’Brien said.


1/ This site seems has great Categorization:

2/ text book based categorization:

3/ Youtube for education: ( check api for easy # of reviews , total views etc.. matrices )

4/ Khan Academy: check API

5/ Standord , MIT open cousseware  etc..