Software As Service

Windows 8 Programming Stack

2011-09-13T11:27:00.000-07:00

My take with few additions

Original Slide from MS

SIlverlight and XAML are not dead but HTML 5 and Javascript are supported out-of-the box.

Good summary available @ http://www.zdnet.com/blog/microsoft/microsoft-to-developers-metro-is-your-future/10611

Numbers and Pictures!

2011-08-15T21:48:00.000-07:00

Windows Phone 7 app

2011-04-13T23:36:00.001-07:00

Got windows phone 7 app going over the weekend. Hoping that will get new Windows Phone 7 codebase -"Mango" soon to build new cool applications

Above : Schedule application for Doctor and working Win Phone 7 tweet application

Push Pull

2010-11-20T14:43:00.001-08:00

in .NET, Reactive Framework provides great async programming model. More details @ Reactive Framework

Evolution of Data and UI

2010-09-26T19:31:00.001-07:00

Healthcare Interoperability 101

2010-06-28T00:17:00.001-07:00

In the US healthcare, there is a lot of buzz around "Interoperability". Mostly driven by standardization bodies and vendors, this discussion is lost in translation. Just count number of standards, HL7, LOINC, SNOMED, DICOM, CDA, AJCC, FORDS, etc. Don't worry if you don't know a few of these standards – Google will lead you in the right direction.

For system integrators, challenge is in synchronizing the relevant information and to facilitate the prompt decision making. Mostly the source data is stored in a relational format in the underlying RDBMS systems like SQL Server, Oracle, DB2, MySQL etc. In some cases, data is stored in legacy systems on mainframe computers in EBCDIC format. For example VistA, the Veteran Administration's aging Electronic Health Records (EHR) system written in MUMPS.

A good analogy would be to compare healthcare interoperability landscape with the United Nations General Assembly. In the UN, we have more than 150 countries and their representative speaking in hundreds of different languages and numerous dialects. Everyone is concerned with "Global Peace". And as was explained by one UN employee, the challenge is to establish the common ground, and ensuring that the message is not lost in translation. We in healthcare are facing the same challenge – for us, it's an interoperability challenge. For system healthcare integrators, interoperability is an ongoing struggle. Consider the following figure

Figure above represents the simplistic view of diverse message formats used in every day healthcare information exchange. Many expert working groups are investing a lot of time and energy in formulating these standards, and keeping them up to date. Most of these messages carry almost identical information like patient demographics, albeit in its own format. For example, X12 Eligibility request and HL7 patient demographics information. In the source data store, patient information will mostly be stored in the same location. Challenge is in figuring out the real cost of supporting these diverse message sets for system integrators like EMR/EHR vendors, and for the end users like providers and hospitals?

Time and again, these standards are presented as panacea for all healthcare data integration issues. Each group claims universal support and wide adoption on their website, and vendors supporting them use it wherever possible. Challenging or questioning their relevance is a sin. From BI system to PACS vendors, everyone is driving this bandwagon. IMHO, standards can resolve an interoperability issue is a myth. Standards are part of this puzzle but not the puzzle itself.

Another issue in interoperability domain is related to the special cases / exceptions. For example, In the US labs market, LOINC is a well established standard. But there are some reference labs where LOINC is not a good enough solution. So we end up with the broken system in which we implement LOINC plus custom codes. It's like writing 90% of the blog post in English with remaining 10% in some other foreign language. Supporting such special requests breaks the interop logic flow. At the implementation level, such requests are either implemented via lookup tables or through custom logic built inside the interop / rules engine.

Finally, the uniqueness of healthcare presents its own challenge. Consider the specialty like cancer care and in that specialty, a very specialized vertical like Brest Cancer treatment. Brest Cancer treatment and survival statistics reporting demands some special attention. Hence, we end up with FORDS - Facility Oncology Registry Data Standard. FORDS provides definitions and detailed instructions for coding patient diagnosis, treatment, and outcomes. Now, standards like FORDS play an important role in the cancer treatment domain. But for the system integrators, this is one more message format to deal with. In the end, we have to deal with multitude of interoperability challenges as explained below

Conclusion

Interoperability requirements will evolve with time. No one standard / group should try to design "Grand Daddy" of all these systems. Any such attempt will create a gynormous blueprint, practically impossible to implement.

References

Principles of Health Interoperability HL7 and SNOMED

What type of company are you working for?

2010-03-12T17:10:00.000-08:00

No great company can be built on revenue model – everything should start with product. Apple, BMW, and GE – everybody had a great product and then they built revenue model around it. If we drive our development to catch up with revenue, we will be in catch-up game all the time. We will end up adding a lot of functionality for anybody who wants to buy. Every opportunity is billion dollar one and every customer is God! We get it, but if we don’t know where we want to go – any road will take us there…

Are you working for a product driven company or revenue driven one? Answers are not simple as revenue will drive the product, and product will generate revenue. But there is a litmus test, if your short term plan is in flux and you bump on new keyword every three to five weeks, chances are you are driven by sales organization. If you have people talking about same technology for long time, and have a capacity built around it, then you are working for a product driven company.

For example, iPhone, Google, ebay was not built to make millions / billions and 110% growth. First the product was designed and developed followed by growth. Now anybody trying to catch–up with these companies are investing 10 bucks, and want 40 back in two years. And we all know where this strategy is going.

Alas! We know – We understand and then We ignore…what type of company are you working for?

Gen next coming

2010-02-26T22:12:00.000-08:00

Barbie The Computer Engineer...

Freash from Boot Camp

2010-02-13T10:43:00.000-08:00

I just got back from Silverlight 4.0 Microsoft boot camp. It was great experience [much better than a three day conference]. OOB,MEF,RIA web service,isolated storage,local mesh and much more...

What we saw in these four days in Redmond is really amazing, and talking to silverlight dev team was a great experience.Friends, river of possibilities is flowing high - its just a matter of jumping in and being part of the fun ride...

I am working on a silverlight 4 test app. Will blog a bout it when its ready.

Till then, have fun, stay in touch and be safe!

Ciao!

Design 101

2010-01-21T07:25:00.000-08:00

I was reading "Dreaming in Code" and thinking about many project I worked on in my career...

And the thought of production tragedy kept coming at me. So finally got it...

When Design is a disaster and Implementation is catastrophe - production will be Tragedy!

SOA: CAPEX Vs OPEX

2009-12-27T22:02:00.000-08:00

When is your Information Technology investment in general and Service related investment in particular is CAPEX and not an OPEX? Let’s consider an example, if service is a value-add then money spent on it will be CAPEX, otherwise if it is something you have to do to keep your product alive – it’s definitely OPEX.

From architecture point, CAPEX services can be developed in an isolated environment and tied back to the product via satellite interface. Many such services are offered via browser and charged on pay-per-use billing model. On the other hand, core business services like messaging and security are integral part of the product and are tightly integrated with it. Mostly, customer will end up paying for OPEX service in one way or other.

Recently, my cell phone provider offered me additional data storage for fixed cost per month. This is a good example of a CAPEX service. Same provider is charging me fixed price for each text message [since I don’t have text plan] – I guess, for the provider, this is an OPEX service.

There are many things we consider while evaluating any technology including distribution model. With SOA, this distribution channel and CAPEX / OPEX model will decide many things like coupling architecture, SLA and revenue projections…

**I am not an accountant and do not understand the nuances involved in this CAPEX Vs OPEX discussion. So feel free to correct me …

Happy Holidays!

Ref:
http://www.stratetect.com/2008/06/capex-vs-opex-what-is-the-difference/

X12 and HL7 view of the patient

2009-11-03T12:18:00.003-08:00

Impedance mismatch

2009-10-18T11:57:00.000-07:00

Healthcare Demo App on SQL Azure Platform

2009-10-02T23:12:00.000-07:00

In our Azure user group meeting and at the LA CloudCamp, I heard many people asking about support for entity framework on top of SQL Azure platform. The best way to test / ans / find out is to build an application.

So I have developed a healthcare app [provider claim lookup] on top of SQL Azure. This app is based on "Code Far" model -i.e. app is running of the hosted server but data is stored in the cloud.

Developed using : Dynamic Data Entities Web Application, Entity Framework, SQL Azure, ASP.NET / C#

Here is a link http://www.zimbatech.com/healthcaredemo/

abhi
www.zimbatech.com

LA CloudCamp -Data in the Cloud

2009-10-01T15:27:00.000-07:00

We had a very good CloudCamp in LA. It was my first unconference – I was not sure what to expect and what I will learn. But at the end of the day [around 11.45 PM or so], when I was walking up to my underground garage on the corner of 5th and Olive, I felt really good about it. It was on the fly brainstorming session with 100 plus technology related folks.

The way this camp was conducted is impressive and food [please read it as free food] was awesome. They had unlimited beer for those who would like to climb up in the cloud before getting into any serious conversation…

We focused on the general theme of data in the cloud. I started the conversation with CAP [not CRAP]. C: Consistency, A: Availability and P: partionshing [a.k.a. load balancing, scaling etc.]. It is mathematically proven that one can have any two of these three qualities in any massively distributed system. Now if we are building an app for the cloud – this principal is very important as there is a network in the middle… it was a discussion that could almost go on for days if not weeks, and we had to wrap it up in half an hour. So the conclusion was twofold – know the limitations and choose what you want before you build your app – you can have any combination of CAP – viz – CA, AP or CP but not all…

Then Lynn Langit of the Microsoft presented on SQL Azure. It was a very good, house full presentation. Our small room was jam packed to its limit and Lynn did a great job of introducing this RDBMS in the cloud. Yes, we heard all those legitimate concerns one more time – how can you build a real database with 10 GB, and what about replication? But as Lynn said this is V1 [and we know from our experience that MS gets the right product out with V3]. I learned one important lesson in this session – when there are non-microsofties around – explain every acronym you use. For them PDC and RTM is like JAOO to the Microsoft community.

Our final talk was on scaling the data in the cloud. From what I understood [which might be way off the mark], there is altogether other alternative to the RDBMS model. Things like Tokyo Cabinet and hadoop , HBASE, CouchDB, etc. [WOW – I remembered all these things]. The point of this discussion was, start thinking outside the box. There are other ways to think about transactions – like BASE, and ACID is not the only way to achieve the consistency. This session was more techno- philosophical. Take away, as per our DBA friend –“RDBMS is crap, start thinking about alternatives”. In the end, the data structures you want to use depend on the type of applications you want to build. Facebook and banking app are two extreme end points on this scale, and have their unique requirements. Albeit, both of them deal with large datasets…

In the end, walking back to the parking lot, I heard this interesting comment –“I went to watch a movie and they told me to act in it, there was no Tom Cruise or Don Box, Lary Ellison in the room, and I ended up presenting the show. Oh! Well – thank god my wife was not in the room…please pardon me if I said something stupid, you know I was little bit drunk…”

abhi
www,zimbatech.com

SQL Azure Object Browser

2009-09-26T13:09:00.000-07:00

Yesterday, I did a blog post on how to alter a stored procedure. On Microsoft Azure Forum, Gaurav has suggested two very good options. Both of them are a scale down version of SSMS - but are way better than the existing support of SSMS for SQL Azure - they provide decent object browser and you don’t have to cancel the login first time you connect to the SQL Azure database...

1. Cerebrata supports Windows Azure Platform. An online demo can be found on

http://www.cerebrata.com/Blog/post/Browser-based-SQL-Azure-Explorer...

I am impressed with the functionality offered here

2. SQL Azure Manager by http://hanssens.org/post/SQL-Azure-Manager.aspx

This is a ClickOnce app and only supports table and views but you can run your TSQL here. One can use a combination of these two apps to simulate almost 75% of the SSMS support and is good enough for most of the routine stuff.

abhi
www.zimbatech.com

Alter Stored Procedure in SQL AZURE

2009-09-25T23:02:00.000-07:00

Absence of object browser in SQL Azure throws many challenges. For example, how would you update a stored procedure in your SQL Azure database? The challenge is to get the source code from the cloud database.

select * from sys.objects

will only display the objects in your database and not the source code for any stored procedure or view etc.

Here is my hack to get the source code for any stored procedure.

1. SELECT * from information_schema.Routines

Will give you the list of all stored procedures. For example you want to alter the stored procedure usp_Test. Then

SELECT routine_definition from information_schema.Routines where specific_name ='usp_Test'

Now copy the contents of routine_definition – this is the source code for usp_Test. In my case this is

CREATE PROCEDURE usp_Test AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON; -- Insert statements for procedure here select count(*) as TotalVisits1 from visits END

3. format this code

CREATE PROCEDURE usp_Test
AS BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
select count(*) as TotalVisits1 from visits
END

4. change CREATE PROCEDURE to ALTER PROCEDURE

ALTER PROCEDURE usp_Test
AS BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
select count(*) as TotalVisits1 from visits
END

Update the source code as required and execute the TSQL

5. This will update your stored procedure in the cloud database.

I guess, best practice would be to mantain a local copy of your database and keep it in sync with your cloud database. That way we can run the code on our local copy and just run the script against the cloud database.

Oh! Well – we are just learning and I did not have a local copy of my test database. Again, this is not an elegent solution but it does work, so if you can recommend / find any better solution – please let us know…Thanks.

SQL AZURE Service

2009-09-21T17:10:00.000-07:00

Finally, I got the SQL Service up and running. It is running of the hosted server

MyCloud Service

While working on this app, I found some interesting things. Here is a short summary

1. select * from sys.objects IS YOUR NEW OBJECT BROWSER

2. truncate table tablename will not work in SQL Azure - yes,drop and delete does work.

3. select @@servername will not work but select @@version does work

4. DO NOT TRY exec sp_help and exec sp_who – it will not work

5.Insert WILL NOT WORK if you forget to add a primary key on your table - For example

create table test
(
my_id int,
my_name varchar(10)
)
insert into test values (1,'abhi')
and you will get an error –“ Heaps can not be replicated tables. Please create a clustered index for the table.” . Just add a PK on my_id and things will work as expected

6. Migrating data from your local DB to the cloud is not easy - check out >http://www.stephenforte.net

7. Copy connection string from your >https://sql.azure.com/ServerInfo.aspx page - this is the easiest and fastest way to connect your app with SQL Azure

Also,I will be presenting on SQL Azure in the upcoming SoCal Code Camp 2009 @ USC

MVC

2009-09-19T17:44:00.001-07:00

Evolving Architecture – Breathing Code

2009-09-17T12:23:00.000-07:00

Gone with the wind…

2009-09-16T16:36:00.000-07:00

Recently, I drove almost 85 miles for an interview. When I entered into the office, I was greeted by a very enthusiastic developer. And then came the moment of truth – he walked me into a room and told me to take a hands-on programming test. OK. The test was on VB6 programming. Well, what happened next is a very funny story, but it kept me nagging that I haven’t thought about VB environment for long time…with all this .NET code around, I just forgot about my old pal VB. Yes – it’s been almost a decade for me when I wrote any code in VB. And then while talking to somebody on COM/DCOM horror stories – I was told that the official support for VB development environment is gone. I found following post on VB resource center

“The Visual Basic 6.0 IDE will be supported on Windows Vista and Windows Server 2008 as part of the Visual Basic 6.0 Extended Support policy until April 8, 2008… ”
From http://msdn.microsoft.com/en-us/vbrun/ms788708.aspx

Yes – VB runtime will be supported till 2019, but support for Visual Studio 6 is gone. Well, everyone using VB 6 is aware of this fact, but for me, on personnel note – it is a weird feeling...

"I have forgot much, Cynara! gone with the wind."

Graph of diminishing questions

2009-08-21T23:15:00.000-07:00

How do you feel if somebody asks too many questions?

Well, whenever we have a new team member joining our group – we all go through the same experience. I call it - graph of diminishing questions [as shown below]

We see one of the following reactions or some combination of it

1. why s/he is asking so many questions - come-on it’s a simple business application - and you are hired to work on it - go figure it out - we gave him / her access to all the systems, code, database - what more can we do - I mean put some break points - run some queries - go figure it out on your own - that’s why you are hired - don’t ask me all these stupid questions?

2. I am not sure why s/he is not asking any questions. If you don’t understand then just ask us. But please don’t say yes when you don’t get it. You know - just yesterday, I was at his/her desk, and by looking at the screen, I can tell you s/he is lost, I don’t think s/he knows anything about the system - and I am not sure why s/he is not asking any questions?

3. Well s/he is a smart person but I think – I don’t know - s/he might have over promised in the interview and now struggling - I think s/he is not that smart as was told to us [by somebody – may be our boss…]

4. We don’t do too much training here - we throw the baby in the water and if she can swim - she can stay

5. We do work with new people and explain them the system and also help them understand the real challenge

I can go on and on and on, but I guess the point is simple - what do you do? I am sure almost everybody wants to opt for no 5, but in reality we are somewhere between 1 and 4. Challenge is to change our culture and look back at our own experience, and remember the day when we were new. When everything looked like a big mystery and intimidating nightmare. We had no clue where to start and what to do. This will force us to help others in understanding the mess [sorry software] that we help [or were paid] to build...

How many CPUs your operating system can handle?

2009-06-11T17:06:00.000-07:00

How many CPUs your operating system can handle? 2 / 4 / 8 – many a times ans is very simple – I don’t know? How to find the answer? Here is one easy way to get to the bottom of this issue. Go to the Task Manager and right click on any process , and then click on the set affinity option as shown below. You will get the answer. Note: this is the number – how many CPUs can be managed by your OS and not the underlying hardware.

And here are the specs for a machine I used in this excercise

Multiplexing strategy for reducing software licensing cost

2009-05-03T18:24:00.000-07:00

Software licensing is a complex and confusing topic. Most of us know how to use and master any given software like SQL Server, Oracle, or Crystal Report etc. But purchasing a software and figuring out the real cost is a challenge. Questions like do you want to go with named-users or per core licensing or on the basis of number of processors or total number of CPU’s are confusing. For example, Microsoft will charge you based on the number of processors in your server irrespective of number of CPUs / core per processor and Oracle will treat each core as half the processor. For example, on 4 quad core server [4 processors with 4 CPUs on each processor = 16 CPUs or cores], SQL server will cost you for 4 licenses and Oracle will result in 8 licensees [16 * 0.5 =8] [1]

Now this might be acceptable for enterprise grade tools like RDBMS or reporting solution. But many a time we end up buying 8 or 10 copies of small commodity software used by a department or a group of users working on a special project. Most of these tools are sold on per instance basis. So we end up paying for 10 copies and installing it on individual desktops. This also results in maintenance nightmare.

There is a better way to deal with such commodity tools – strategy known as multiplexing. It’s very straight forward – all you have to do is to install one instance of the commodity software on your central server and write a wrapper around it. The wrapper can be exposed over the network [LAN / WAN / Internet] using http, https etc. Yes, you will have to write a web application that will expose the interface for the commodity tool. Many a times, this strategy will work like a charm [except if licensing agreement for the commodity tool explicitly deny the permission for any such exercise]. Note – this does not involve changing any of the bits / code in the commodity software – all you are doing is to expose its public interface over the network. Threading and deadlocks might pose some challenge when shared resources are simultaneously utilized by many users. But this can be avoided by placing an explicit lock on shared resources like file folders. Additionally, this public interface can be modified to accept the inputs from internal resources like local databases, file system etc.

If used judiciously, multiplexing can deliver a great business value.

Reference:

1.http://www.microsoft.com/Sqlserver/2005/en/us/special-considerations.aspx

Web 2.0 and Cloud Computing

2009-04-20T18:15:00.000-07:00

It is always good to compare different technologies. That way we can see whether the technology is maturing with time and is worth considering it for real. But the challenge is to find a tool that would help in this endeavor. I found “Gartner Hype Cycle” [GHC] really effective in comparing different technologies and their evolution.

So I wanted to see how web 2.0 is doing over last three years and where does cloud computing stand on this technology curve. I always believed that image is worth thousand blogs…so here you go – GHC for 2006, 07 and 2008 and the evolution of web 2.0 vs. cloud computing. ..

Reference
for 2006
http://www.saastream.com/my_weblog/images/2007/10/02/gartner_hype_cycle_emerging_techn_4.jpg
for 2007
http://3.bp.blogspot.com/_7vNv3GLH8Mo/SKwvl_0JTqI/AAAAAAAAAG4/3pnTC4Q4gp8/s400/hype-cycle-for-emerging-technologies-2008-400.jpg
for 2008
http://www.flickr.com/photos/lafabriquedeblogs/2796357787/

Virtualization : as experienced from ground zero

2009-04-19T11:55:00.000-07:00

Virtualization is a big theme in the contemporary enterprise architecture. Many documented case studies highlights the virtualization benefits including better hardware utilization, grater ROI and lower TCO. This deal is so great that you can’t overlook this option…

But, and this but is a big one. But the reality is not that green. From software point of view, it is not able to utilize 100% of the physical infrastructure. Like in our example, we have 8 CPUs and 128 GB of RAM, but each virtual machine can only use up to 4 CPUs and 64 GB of RAM. Systems like RDBMS thrive in many-core / multi-processor environment. So by limiting the number of CPUs or memory, we are minimizing its capacity. This is what we experienced when we decided to use a hypervisor [and this is mostly true for any hypervisor].

In future version of hypervisors, this limitation will be fixed. Based on the processing load, each VM will be able to optimize the physical resource utilization. But as of today, there are some hard limits on no of CPUs and RAM each VM can use.

So to conclude, in our test case – let’s compare machine A with 8 CPUs and 16 GB of RAM with machine B with 8 CPUs and 128 GB of RAM. Machine B is virtualized and is used to run 2 VMs with 4 CPUs each and 64 GB of RAM. Both the VM’s on machine B are operating in parallel and are used for running an instance of SQL Server 2005 and a file server. Which SQL Server instance will run fast – one that is running on machine A or on machine B? What if we bump up the RAM in machine B up to 256 GB? These are some solid question one should consider seriously before jumping on the virtualization bandwagon. Yes, all these issues will be fixed in the future versions and all vendors are working on it. But from pure architecture point of view, as of today, one should consider these limitations seriously.

A lot will depend on the processing load and type of applications running on these virtual machines. For busts and spikes – you need a ton load of RAM and huge processing for a while but after that all that capacity is just idling around. What if that bust or spike is the reason for provisioning such a huge hardware capacity? Can we run this busty system in a virtualized environment and let it suffer because of VM’s limit on no of CPU it can handle and maximize our hardware utilization or go the traditional way and provision a big machine just to handle this one mission critical load efficiently and effectively? These are some critical questions one would face while moving the production applications in a virtualized environment. There are no easy answers and the only way to insure the success is by doing as much testing as possible.

On the Benefits of Learning Multiple Languages

2009-02-01T21:40:00.000-08:00

Finally, I got to the pile of magazines I wanted to read for long time. I found this article in Visual Studio magazine. I liked the title and started reading it. The basic premise is – “Learning other programming languages can make you more fluent and give you a better understanding of the language you depend on primarily.”

So I started coding in the language I know the best – C# and wrote some code


using System;

namespace demo
{
    internal class Test
    {
        public static void Main()
        {
            const int i = 2;

            //static method call
            Console.WriteLine(IsEven(i));

            //generic delegate
            Func<int, bool> f = IsEven;
            Console.WriteLine(f(2));

            //anonmous method + lambda
            Func<int, bool> f1 = j => j%2 == 0;
            Console.WriteLine(f1(2));

            Console.ReadLine();
        }

        public static bool IsEven(int number)
        {
            return number > 0 ? number%2 == 0 : false;
        }
    }
}

Now, I wanted to convert this code to visual basic. Interestingly, I found a decent conversion method to get this thing done. I used .NET reflector. I used reflector to disassemble C# .exe and then to convert the code to VB. Reflector did a good job and produced following VB code


Friend Class Test
    ' Methods
    Public Shared Function IsEven(ByVal number As Integer) As Boolean
        Return IIf((number > 0), ((number Mod 2) = 0), False)
    End Function

    Public Shared Sub Main()
        Console.WriteLine(Test.IsEven(2))
        Dim f As Func(Of Integer, Boolean) = New Func(Of Integer, Boolean)(AddressOf Test.IsEven)
        Console.WriteLine(f.Invoke(2))
        Dim f1 As Func(Of Integer, Boolean) = j => ((j Mod 2) = 0)
        Console.WriteLine(f1.Invoke(2))
        Console.ReadLine
    End Sub

End Class

The only point it tripped is on the lambda expression syntax =>. So, I had to do a little bit of Googling to find the correct VB syntax. And, finally got the VB code like


Friend Class Test
    ' Methods
    Public Shared Function IsEven(ByVal number As Integer) As Boolean
        Return IIf((number > 0), ((number Mod 2) = 0), False)
    End Function

    Public Shared Sub Main()

        Console.WriteLine(IsEven(2))
        Dim f As Func(Of Integer, Boolean) = New Func(Of Integer, Boolean)(AddressOf IsEven)
        Console.WriteLine(f.Invoke(2))
        Dim f1 As Func(Of Integer, Boolean) = Function(j) j Mod 2 = 0
        Console.WriteLine(f1.Invoke(3))
        Console.ReadLine()

    End Sub
End Class

I enjoyed this exercise. In fact, in the same edition of the VS magazine, I found couple of interesting articles - What VB Devs Should Know About C# and What C# Devs Should Know About VB.

If you are involved in any migration effort from VB to C# or vice versa, or work in the mix environment with a lot of VB and C# code co-existing peacefully , then you will find these articles really useful.

Towards Distributed Applications…

2008-11-02T12:06:00.000-08:00

2008 is the year when we saw the commercial emergence of the many-core / multi -core hardware architecture. As a result of this, field of distributed computing is really buzzing with a lot of activities and cool technologies. Two such projects that attracted my attention are project Volta and DryadLINQ in Microsoft domain and Lively Kernel in the Java world. Let’s focus on Dryad and Volta first.

One common thing about Volta and DryadLINQ is that they focus on making distributed computing easy for the common programmer like me. [DryadLINQ documentation refers to this class of programmers as ordinary programmer – LOL!] . The strategy here is to abstract away the underlying complexity in building the distributed systems and to minimize the disruptive impact of the new technology.

This goal is achieved by focusing on different levels of the .NET implementation stack. This way, as a developer, I can still write my same old C# / VB sequential, LOB code and the technology will transform it into a distributed application.

As with any new technology, there will be few bumps on the road. At the time of writing this post, I found following message on the Volta site –

“Project "Volta" Temporarily Unavailable”

Good news is that big vendors like Microsoft and Sun are taking the bull by the horns. There is no one right answer in solving this complex problem of converting existing sequential , single processor LOB applications into multi-core/ many-core enabled , inherently parallel, distributed applications. We will witness multitude of solutions on hardware and software level. We have seen this gold rush before in the good old days of RDBMS emergence. Let’s hope that same thing will happen with the distributed computing infrastructure.

For more details on Volta and Dryad, check out the following links and publication

1.http://channel9.msdn.com/posts/Charles/Erik-Meijer-Volta-Wrapping-the-Cloud-with-NET-Part-1

2.Volta: Developing Distributed Applications by Recompiling, IEEE Software Sept/Oct 2008 issue

3.http://research.microsoft.com/research/sv/dryad/

Caching in the Distributed Environment Slides

2008-10-27T12:23:00.000-07:00

I did a presentation on "Caching in the Distributed Environment" at SoCal Code Camp 2008. Here is the link from where you can download this presentation

http://www.scribd.com/doc/7564192/Caching-in-the-Distributed-Environment

Let me know if you have any questions / suggestions

thanks.

abhi

Caching in the Distributed Environment

2008-10-04T16:16:00.000-07:00

Microsoft Architecture Journal has published an issue on Distributed Computing. A pdf copy of this issue can be downloaded from MAJ Issue 17

My paper on caching is included in this issue. I will be presenting this paper at SOCal Code camp 2008.. In this presentation, we will cover the fundamentals of caching, different caching patterns [for example, shared, primed, demand, transactional caching] and some real life caching examples. We will also discuss about the project Velocity - MS distributed caching platform.

See you @ the code camp

Finally, I learned something

2008-09-13T14:10:00.000-07:00

I had a chance to talk to one of my friend who is working on his dissertation. He is focusing on psychological aspects of success. After a long discussion with him about many topics, one thing really stood out by itself. Success is all about creating realistic targets and achieving them with pragmatic efforts. For example, if you can lift say 35 lbs/kgs then go for 35 or say 36-37, but beyond that you are in the stress zone. Now if you set the target of lifting say 40 lbs then give yourself some time – a realistic one would be a few weeks – anywhere between 2-3 weeks. If you try to achieve this overnight then you are in the stress zone. Be realistic is what I heard almost every time we talked about success.

I am definitely overweight. My weight should be in the 150 lbs range and it hovers around 162 lbs. So I belong to the club of 60% overweight Americans. If I set the target of 150 lbs in 3 weeks, I am in the stress zone, but if I do it in say 8 weeks – that’s more realistic.

Another stress factor was really a news to me. The Focus – almost every job requirement on DICE and Monster has it – we need someone who can multitask. Multitasking is not a synonym for focus – is it? According to psychologist, multitasking will reduce the quality of your work and will lead you to a stressful situation. So realizing the limits of what is doable and what is not is really important. Yes, we can chat with our friends while seating in a long design meeting, but I don’t think that’s possible if you are in the middle of a refactoring session.

Personally, I would like to avoid multitasking as much as possible. Now I know this is not something my boss or employer would like to know. But I would prefer quality over quantity anytime – anywhere. I have just started reading a WCF book –Learning WCF. My goal was to finish it over the weekend and to get the ball rolling come next Monday. Without realizing, I was pushing myself into the stress zone. Practically, this is an impossible target. So I am going to give myself a few more weeks and try to stick to my plan. I have one more book seating on my desk – Service Oriented Modeling. But for now, I am going to move this book back to my bookshelf. Wow! Finally, I learned something…

A great fit ..

2008-09-07T14:05:00.000-07:00

[And] I think you are a great fit for this…

What is Business? From Nature of the Firm by Coase [1] to the Porter's 5 forces analysis [2], this question is analyzed and explained in numerous studies and research. Still this important question is overlooked in many discussions related to this topic like a role of an architect. Figure 1 is another interpretation of the Marketplace and the Business

Figure 1: The Marketplace and the Business
There are enterprise architects, solution architects and infrastructure architects. Sometime the job description is a combination of all of the above or none of the above based on the situation and the project. A new way of looking at it is in terms of depth and width. An enterprise architect is responsible for managing the big picture and hence is a width base role. Solution architect focus on the project or a particular part of the project like performance or security and hence is a depth based role. Infrastructure architect is responsible for the infrastructure – viz SAN/WAN, servers, scalability, etc.

Architects are also responsible for coordinating operations between all other components of the business like HR, Marketing, Sales, etc. and the IT. Sometimes this means a political position and in other cases it’s a technical responsibility. Enterprise frameworks did an excellent job in capturing the technology component. The political/people part of the puzzle is mostly an on-job learning/training activity.

The role of an architect is to understand the business strategy/vision and implement it successfully in terms of improving existing process or by creating new processes. As explained in figure 1, it is important to understand the reason behind the project. For example, a project to support a new service or product will be totally different from the project focused on improving existing product/service. With a new product or service, an architect has got the freedom to start from scratch with a blank slate. Project focused on improving the existing product/service will mostly be a migration project like upgrading a legacy system, implementing some sort of application integration, etc.

An architect is like a conductor of an orchestra. Although, conductor does not play any instrument, he is responsible for producing the melody bounded by the music rules like the Symphony No. 40 [3].

Oh! What about an enterprise solution architect? The headhunter kept going on and on for almost five minutes. And then he said, you know, you should consider this seriously as their business is doing really good and they are growing really fast. A position with a local, stable, fast growing, privately owned company and yes, the salary is in six digits. I asked him, what is their business and he said does it matter? They are looking for an enterprise solution architect. [And] I think you are a great fit for this…

Resources:

1.http://en.wikipedia.org/wiki/Ronald_Coase
2.http://en.wikipedia.org/wiki/Porter_5_forces_analysis
3.http://en.wikipedia.org/wiki/Symphony_No._40_(Mozart)

David Linthicum on SOA

2008-09-01T23:28:00.000-07:00

Vendor Driven Architecture [VDA] ,Manage by Magazine [MBM], Rabbit Consulting, think strategically and not around the quarter for making the bonuses. I heard all these terms in a SOA presentation by David Linthicum.

Here is the youtube URL - http://www.youtube.com/watch?v=0CbjUNzBV6I&feature=related

Here are some tidbits from this presentation

Architecture is something that you build not buy

Good Architects are expensive

Its up to you to decide what you want to build – SOA Zoo or SOA architecture

How NOT to build EA - signs to look for

Enterprise Architect is a position with no power and no authority

Architects write the documents that nobody read and talk about the things no body listens

ORM Manager

2008-08-22T20:07:00.000-07:00

ORM manager will populate the data stored in the persistent storage like a database in the form of an object graph. ORM manager will use different object mapping strategies like table per hierarchy [TPH], table per type [TPT] or table per concrete class [TPC], etc. in populating the object graph. LINQ to SQL is based on TPH. Hibernate supports TPC, TPH and table per subclass mapping strategy [1]. Following is an example of the TPH.

Table Per Hierarchy ORM implementation

Reference:
1. http://www.hibernate.org/hib_docs/reference/en/html/inheritance.html accessed on 08/21/2008

Meaningful Identifiers

2008-07-21T17:05:00.000-07:00

Anthony, _anthony and anthony were good friends. Anthony is a grown up guy,_anthony is a boy and anthony is a dog. One day, Anthony invited _anthony and anthony to his place for the party. _anthony was not feeling well but decided to tag along anthony. _anthony is too young to drive so they decided to walk to the Anthony’s place. Unfortunately, anthony could not walk so they called a cab. _anthony…

Who cannot walk? A dog or a boy…

Let’s re-factor this story a little bit. Let’s rename Anthony to MAnthony, _anthony to BAnthony and anthony to DAnthony. M for men, B for boy and D for dog.

With these new identifiers this story will be much better [to read and understand]. As in any story or a novel, meaningful identifiers are really important. Identifiers in any source code provide a meaningful token for the underlying memory. Identifiers tell a lot about the program. Just looking at the identifiers like account, debit and credit one can figure out that the system is a financial system.

This is a good read for anyone interested in more details on the way we program

VS 2008 Debugger going crazy?

2008-07-14T18:21:00.000-07:00

Look at the code below and put the breakpoint on line
if (_s == null)

observe the behavior when we do something like
s2 = Singleton.getSingletonInstance();

using System;

namespace Pattern
{
class Program
{
static void Main(string[] args)
{
Singleton s1, s2;

s1 = Singleton.getSingletonInstance();

s1.instanceCount = 100;

s2 = Singleton.getSingletonInstance();
}
}

sealed class Singleton
{
private static Singleton _s = null;
public int instanceCount;

private Singleton()
{
}

public static Singleton getSingletonInstance()
{
if (_s == null)
{
_s = new Singleton();
}

return _s;
}

}
}

When the breakpoint will hit, try watching the value of _s. The watch window will pop endlessly all over the screen when you click on the following + sign next to the static members icon.
Screenshot:

SoCal Code Camp 2008

2008-06-20T09:54:00.000-07:00

I will be presenting at Next Code Camp June 28th and 29th at University California San Diego Extension [www.socalcodecamp.com]

Topic: Using LinqDataSource with ASP.NET data controls

When: 3:00 PM - Sessions Room 110 on 06/29/2008 - driving directions can be found here

Check out LinqDataSource Sample

We will work on this sample in session.

Thanks

LINQ to SQL model

2008-06-06T12:20:00.000-07:00

Type of Exceptions

2008-04-19T21:28:00.001-07:00

Nullable Object Pattern

2008-04-16T10:01:00.000-07:00

Experience

2008-04-04T11:08:00.000-07:00

Logic

2008-02-19T21:31:00.001-08:00

Wrapper Application

2008-01-08T20:41:00.000-08:00

Architecture pattern : Coupling

2007-12-25T20:14:00.000-08:00

Software Development

2007-11-29T14:50:00.000-08:00

Aspect Oriented Programming

2007-11-11T23:19:00.000-08:00

Structural inefficiency in Health Care Network

2007-10-27T13:57:00.001-07:00

Focus

2007-10-14T14:17:00.000-07:00

Disable Browser back button

2007-10-04T11:47:00.000-07:00

"No back button when you do this."

code:

"a href="http://soaas.blogspot.com/" onclick="javascript:location.replace(this.href); event.returnValue=false; ">No back button when you do this. /a"

Evolution of Computer Systems Architecture

2007-09-30T13:24:00.000-07:00

“Had we had such a progress in transportation as we have in computers, one could travel cost to cost in few seconds at a cost of few pennies…”

IT Infrastructure Planning

2007-09-19T16:48:00.000-07:00

Outward Software Development Model

2007-09-04T15:34:00.000-07:00

Outward Development Model [ODM] is very common in projects involving op sys development, application framework development, platform integration tools, etc. Is there any real alternative to this model when we are working on such a big project with very wide impact? TDD, XP,RAD, DDD…

Can Rome be built in a day?

Object Relational Mapping

2007-08-24T15:48:00.000-07:00

C# Compiler Mysteries

2007-08-02T19:04:00.000-07:00

This is an ERROR

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
SortedList sl = new SortedList();
}

This is NOT an ERROR

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
SortedList sl = new SortedList();
}
}

Want to know more about this , check out
http://msdn2.microsoft.com/en-us/library/xaw06638(vs.80).aspx

And here you will find more opinions
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1780871&SiteID=1&pageid=0

Role Permission Explosion in Role Base Access Security [RBAC]

2007-08-01T12:39:00.000-07:00

Formula: nCr = n! / [(n-r)! r!]

n : Possible Permissions

r : Possible Roles

So for 3 Permissions, possible roles are

3C1+3C2+3C3 = 7

So for 3 permissions, we have 7 possible roles in 1 application. If we have 2 applications then the no of roles will be 14.

Challenge

How to minimize / manage roles?

Solution:

By Grouping

Role Hierarchy
Role Linking

By Enforcing Business Rules

Application Performance and Simplicity

2007-07-06T10:20:00.000-07:00

Filter and Pipe with Publish and Subscribe Flavor

2007-05-15T18:13:00.000-07:00

Filter and Pipe Pattern for SaaS

2007-05-15T11:57:00.000-07:00

SaaS in Action!

2007-04-23T12:13:00.000-07:00

Check this out

http://www.clocklink.com/ENG/gallery.htm

Just copy the html code from this website on any webpage. This script will give you a decent , ajax enabled world clock. Cool app and good example of software as service.

SaaS : $19.3 billion by 2011

2007-03-14T12:10:00.001-07:00

Check this out

"According to Gartner, the market for SaaS applications grew by 26 percent last year, from $5 billion in 2005 to $6.3 billion in 2006. The consulting firm expects demand for SaaS to continue growing at a 25 percent compound annual rate over the next five years, to $19.3 billion by 2011. Most of those dollars are going to new entrants rather than established software vendors like Oracle (Quote), SAP and Microsoft (Quote)."

For full story - check this out "Vendors Missing the SaaS Wave By Michael Hickins " [http://www.aspnews.com/news/article.php/3664361]

More Power per Source Code line

2007-03-13T11:11:00.000-07:00

Now this example is just hypothetical and grossly overestimation of the reality. But the point is, we are writing less line of code to achieve same results. In my opinion, this is because

1. Powerful programming constructs and smart compilers [for example, C# closure]

2. Advances in Algorithm and Hardware

3. Greater level of code level abstraction

For Example, Consider following example in C# and same code compiled by MS CLR

[Example from : http://www.thinkingms.com/pensieve/CommentView,guid,fd10bfa8-1aeb-4353-84c8-cd80e418424f.aspx]

// Display powers of 2 up to the exponent 8:
foreach(int i in Power(2, 8))
Console.Write("{0} ", i);

Now this code will be compiled as

public static IEnumerable Power(int number, int exponent)
{
int counter =0;
int result = 1;
while(counter++ < result =" result">
{
result = result * number;
yield result;
}
}

So the point is, foreach is an elegant syntax. It also hides a lot of complexity at the programming construct level. Now, the level of abstraction and its impact on performance is altogether a different topic.

Still, if we are using high level language like C# or Java for developing business applications then this abstraction and syntax simplicity is good. [This argument is based on a long discussion with my friend Jon Saltzman]

Again, I heard an argument that this abstraction will result in increased programmer productivity. I am not sure about that. Anyway, point is modern programming languages provide more power per source code line

Gartner Hype Cycle

2007-03-09T15:00:00.000-08:00

Time and again I have seen and heard discussion on the rise and fall of a particular technology. With multi core processors and Internet based distributed programming – this debate is getting sharper by each passing day.

I found one tool to analyze the rise and fall of any technology against the proven industry data – “Gartner Cycle”. Here is my take on current state of the technology...

One More Security Model

2007-02-18T15:15:00.000-08:00

Here is another security model. We used this in one of our application.

Algorithm

1. Accept Username and pass it to the database in plain text
2. At Database, from username find out the corresponding salt value
3. Encrypt the salt value at database end and pass it on to your app
4. Decrypt the salt value at app level and compute the hashed password at app level
5. Hashed password = salt value + user password
6. Encrypt the hashed password at app level and pass it on to database
7. Decrypt the hashed password at database level and compare it with one stored in database
8. If match is found - pass 1 else pass 0

Assumption

1. No password is stored in database; only hashed password is stored with corresponding salt value and username
2. We have used identical .NET assembly [same algorithm for encrypt,decrypt and hash mechanism] at app and database end. .NET CLR integration is used to implement this dll functionality inside database
3. Webservice is used to communicate with database. HTTP Endpoints and HTTP.SYS is used to create this web service

Platform

Windows 2003, .NET 2.0 and SQL Server 2005,ASP.NET

Business Models of the Future

2007-02-08T17:13:00.000-08:00

Read this interesting argument regarding the Software Business Model of the Future at http://knowledge.wharton.upenn.edu/article.cfm?articleid=1651&CFID=3283734&amp;amp;amp;amp;CFTOKEN=97771900

Gist of this intellectual argument can be summarized as follows

Business Models of the Future

2007-01-30T17:08:00.000-08:00

Difference between ASP and SaaS business model

The extended Application Service Provider Service Model

2007-01-30T12:32:00.000-08:00

The International Association of Software Architects published myarticle on SaaS - “The extended Application Service Provider Service Model” in the December 2006 issue of the “Perspectives of the IASA” magazine.

Abstract

The paper will focus on the process of service delivery in an extended Application Service Providers [ASP] model. The aim of this paper is to establish the unique characteristics of an extended ASP model. Observations in this paper are based on a Service Oriented Architecture (SOA) implementation. This paper discusses the service delivery model, and addresses challenges and benefits of an extended ASP. It will conclude with a discussion of the service implementation strategy.

Direct link for PDF

http://www.iasahome.org/web/home/perspectives?p_p_id=20&p_p_action=1&p_p_state=exclusive&p_p_col_id=null&p_p_col_pos=0&p_p_col_count=0&_20_struts_action=%2Fdocument_library%2Fget_file&_20_folderId=9&_20_name=IASANewsletterDec2006.pdf

Code Camp 2007

2007-01-30T12:28:00.000-08:00

SoCal Code Camp : Software As Service [SaaS] for Developers presentation

What is SaaS? From Salesforce.com to workday.com, many vendors are offering Internet based, hosted software services. This business model is commonly known as SaaS. Presentation will focus on Design and Development of SaaS. We will cover the fundamentals of SaaS, service design guidelines, database considerations, operational and performance issues in SaaS domain. Presentation will be available on-line.

Download this presentation and Demo Application Source code [c#,T-SQL and ASP.NET] from :
http://www.amgsiu.com/infocenter/wp-content/uploads/2007/01/CodeCamp.zip

For Refrence Please check : http://www.iasahome.org/web/home/perspectives [Download the latest issue of the Perspectives!]