Today we read a different paper.  This one is titled Jigsaw : Efficient, low effort mashup isolation by James Mickens and Matthew Finifter. Mashups are web applications that contain code from different principals.  These principals often have a lop sided trust relationships with each other. For example, a page that shows local news may receive data from a news feed component  and a  map component.  The integrating page may want to isolate both components from each other and present them with an extremely narrow interface to the integrators state. Another example might be where a social networking page might embed a third party application and an advertisement.  As we can see this applies to web application rendering content from different microservices.  Securing such a mashup application is challenging because the source of the data may not want to expose anything more than a narrow interface to their private code and data. Jigsaw is a new framework that isolates these mashup components.It is an extension of Javascript language and requires a Jigsaw to Javascript compiler. Jigsaw differs from its predecessors in the simplicity of its syntax to make it easy for a domain to tag internal data as externally visible. It uses the well-understood public / private keywords which developers are familiar with. Also unlike previous approaches, it allows mutually distrusting code to runs inside the same frame, this allows scripts to share state using synchronous method calls instead of asynchronous message passing. Yet it provides strong iframe like isolation, Since the code runs within the iframe, Jigsaw allows code to share state using synchronous method calls instead of asynchronous message passing. Also Jigsaw introduces a new encapsulation mechanism called surrogates. Surrogates allow domains to safely exchange objects by reference instead of by value. This improves sharing efficiency by eliminating cross-origin marshaling overhead.  A developers primary challenge in creating mashups is the wide range of trust relationships between mashups.  Sharing information between principals is desired but often required in explicit and controlled ways. This framework makes alleviates this onus and makes it easier for the developers. By implementing it in Javascript, the framework is available to include as client side scripts. This framework also improves the language' support for encapsulation.

#codejam problem

There are N hot water  taps that can be opened and closed one at a time to fill a reservoir with volume V and temperature T. Each tap has a rate Ri and temperature Ti. Find the minimum time required to fill the reservoir. 

If N == 1,
       if T != T0 return -1;
       return time-taken  = v/R0
If N > 1
     If T < min (T0, T1) or T > max ( T0, T1)
              Return -1;
     If T0 == T1 return time taken = v/ (R0+R1)

        t0 = (V - V * T / T1) / (R0 - R0 * T0 / T1)

        t1 = (V * T - t0 * R0 * T0) / (R1 * T1)
      #The respective contributions are taken into account above and since they are independent they can be opened simultaneously
       Return max (t0, t1);
       Courtesy: Zibada Similar to the deer hike problem mentioned earlier

#codingexercise
For simultaneous flow from more than two taps above, we would have the forms
(V - V×T/T1 -V× T/ T2)/ (R0- R0*T0/T1 - R0*T0/T2)