Category Archives: software development

Generating alternative Solutions to Problems

In the article about problem solving in software engineering, i highlighted the major problem solving steps as:-

  • Define the problem
  • Analyse the problem
  • List/Identify  alternative solutions
  • Select the best solution
  • List instructions that lead to the solution using the selected solution
  • Evaluate the solution

In this post, i will focus on how to generate alternative solutions.The first solution you are arrive at may not be best of all possible options. It is important that we generate as many alternatives as possible. This will allow us to choose the most effective solution to the problem.

To generate alternative solutions, you can look at the problem in different ways. You are argued to find a new perspective that you have not yet thought about. One technique is to quickly list different solutions including those that do not look viable and then try to eliminate one by one and see where they fail. Try combinations of different parts of solutions.

You can also engage stakeholders. Usually stakeholders see problems from completely different perspectives. If you are a developer, involve users, involve sales people and other stakeholders.

Within the same group, brainstorming sessions tend to generate different solutions.  In general, the  more alternative solutions at hand, the final solution will be cheaper, elegant and easy to implement

 

151 total views, no views today

Inspiring quotes on computing

“It is not only the violin that shapes the violinist, we are all shaped by the tools we train ourselves to use, and in this respect programming languages have a devious influence: they shape our thinking habits.”
Edsger W. Dijkstra
“Program testing can be used to show the presence of bugs, but never to show their absence!”
Edsger W. Dijkstra

476 total views, 2 views today

Streamlining Software Development Projects

In most developing countries the software development discipline is emerging. Several private and government entities are in the process of automating different business activities. Just like the software discipline itself, the information technology professional are still gaining expertise in specification and verification of software solutions.Where the clients know what they want, they are not in position to explain it to the developers. And equally less experienced developers find it a challenge to understand the needs of the client.

To overcome this problem, some entities hire a consultant to help manage and supervise the implementation process. That is, there are two different consulting firms involved in the project – one to do the actual implementation and the other to supervise the implementation. They all work for the client, but the supervising firm ensures quality is delivered.
crb

This approach of a supervisor and the contractor is well tested in civil engineering works. Where you will find, the main contractor, the supervisor as independent contractors.

For this work, the discipline has to be mature such that the approaches and documentation are well understood by the different parties in the project. In some projects, this has improved the quality of the project because each contractor has a specific responsibility.

I have seen this approach work in software development with amazing results. Usually the supervising contractor requires domain knowledge to ensure that the engineering product serves the desired purpose. The presence of supervising contractor implies the need for proper specification, documentation and reports because these are part of the main inputs for the supervising contractor. The mandatory need for these documents guarantees a level of a streamlined the software development process.

1,047 total views, no views today

Learning is hard but unlearning is harder

During the week of  27 June – 29 June 2016 i attended the Summer School on Machine Learning and Data Science at the school at Makereree University dubbed “Data Science Africa 2016”. I happen to sit with a colleague who is an experienced and certified Java Programmer. As we paced through the examples on data cleaning using anaconda package, we relied both on new new knowledge and also tried to apply what we have learnt over past years in our professional programming experience.

We aimed at cleaning our dataset to get rid of rows without a value for one of the rows on multiple columns. Our data had a column for Gender and another for TesCondition. Now some of the rows had empty values for Gender, while others had empty values for TestCondition. We learnt that once you have a data frame, then you can apply a condition of the form,

 q1= Dataset[‘gender’!=’’]

And then use it query the data as dataset[q1] and this faithfully returned only rows with a value in the gender column. Our next task was to remove the rows with empty values in the ‘TestCondition’ column. Of course we easily figured out that we can construction another query

 q2=Dataset[‘TestCondition’!=’’]

And apply it to the result after q1.

But then our instincts dictated that we could achieve the same result by using Dataset[q1 or q2] – that is return columns where gender is not empty or testCondition is not empty. However the compiler severely rejected this. For sure we have learn’t and know that logical operation on two Boolean expression should yield another another Boolean. Then our unlearning process hard to begin! We checked the syntax, double-checked the indenting, double checked the expression one by one. Meanwhile we found ourselves a couple of tasks behind the rest of the class. Reason – we could not easily unlearn what we have learnt and believed to be correct overtime.

For a while we kept on trying related syntactical expressions from Java, C, C# and standard Python that were not successful. It quickly became obvious that because we were so convinced about the common usage of logical expression, it took us a lot of time to adjust and enjoy the syntax of the new data science platform. Learning the new syntax was much faster as opposed to the time we spent trying to ‘unlearn’ from the past language.

The time taken to unlearn can vary from individual to individual. And a famously put by E.W.Dijkstra (1995) that ‘The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offense” .Dijkstra further “the teaching of BASIC should be rated as a criminal offense: it mutilates the mind beyond recovery

Indeed I have had comments from programmers as they attempt to cross from one language to another.

From C, C++, Java, PHP to Ruby
Any body who has done programming in this languages understands the importance of terminating statements with semi-colon (;) and strict naming of variables. One programmer could not come to terms with the fact that variable names of the form is_avaialable? Are perfectly acceptable in Ruby.

From C , C++, PHP to JavaScript

The notion of functional prototyping in javascript coupled with variable scoping in javascript has proved to be profoundly different from the typical static scoping most developers with expertise in C, C++ and Java are familiar with. In C, C++, Java the following code will terminate and producing twenty outputs

for(int i =0; i<10;i++){
  for(int i=0; i < 2 ; i++){
    System.out.println( i);
  }
}

while in javascript,

for(var i =0; i<10;i++){
  for(var i=0; i < 2 ; i++){
   console.log( i);
  }
}

will create a an infinite loop.

Have you had a challenge unlearning something?

731 total views, no views today

Why Steal Software When There is Free Software?

Recently, one of the leading commercial software companies in the world has hired one of the leading advocates in town to crackdown individuals and organisations that are using software which is not licensed. That is people engaged in theft of software products — an act that is often called software piracy. In the past, there has been a feeling that most of the software companies are not local and therefore do not have local presence to detect and followup individuals using their products illegally. However, as of today, perhaps with the help of the credit crunch, even the largest companies are determined not to loose any revenue on products that represent their livelihood. Considering the price of these products and current economic downturn,   it may not be possible to pay for them and yet it is not possible to do without.

Actually, there is a better and smarter workaround. There are free software alternatives for all your needs ranging from simple document editing to advanced professional systems. Besides when you pay for the commercial products, you do not really own it, for instance it would be illegal to lend it to your friend or wife. Commercial software products are like buying a car that you cannot even give a driver to drive you or your spouse to pick your daughter from school.

Free software precisely means free of charge, that is software you can get at zero price. Moreover, free software gives the user freedom to use, to study and change it, and to redistribute it with or without changes. That is, you have the liberty to copy and redistribute in modified or unmodified form either without restriction, or with minimal restrictions to ensure that further recipients can also do similar things. Therefore those interested and with the technical know how can modify the software, add value or remove those unwanted features. Think about how often, you wanted to do something with a system, but it could not.

Let me first answer the question that might be developing in your mind – who owns the software if any, and how do they benefit? Precisely, a group of software engineers come together to build systems of interest. The answer is simple, the users do not directly pay for the software, but advertisers pay. In fact, to most commercial products there is a corresponding free software product. If your software needs are typing documents, spreadsheets, then OpenOffice is the answer to your needs. OpenOffice is free, powerful and provides an exceptional user experience. Of course you need an Operating System to start with. An Operating System controls and coordinates the activities of your hardware and other software on it. For free excellent Operating Systems, there are many choices from Linux based variants. My favorite is Ubuntu — “linux for humans”, spearheaded from South Africa. With Ubuntu, you do not worry about computer virus and comes with a collection of other software for all common activities. Be it music players, games, Internet software, e-mail software, they are all available on Ubuntu free of charge.

There is this old adage that free things are usually expensive. Free software is perhaps the first product am aware of to defy this adage, it is given completely free of change and performs better than the counterpart commercial software products. Take a case of Ubuntu, no virus is yet known to attack it. Indeed, the open source community has shown the way for many years: open peer review has proved to be an extremely effective way to detect design flaws, inefficiencies, and security holes.

Today, there are tens of millions of people around the world that use free software. Some free software products such as Apache Web Server command up to seventy five percent of the market. The question I have posed today, is then, why steal software when there is free software? Perhaps, one of the answers is that you are not aware of these free and excellent products. Maybe the one who exposed you to computing literacy had the same problem. There is always the first time, moreover, the free products provide similar or sometime better user experience because they are reviewed by many people. You have the freedom to lend or duplicate and use in anyway. Most important, if you have the competence, it is possible to personalise the software by removing or adding functionality to fit any taste.

1,762 total views, no views today

What About Sub-standard Software Systems

Like any incurable disease it (software) attracts more quarks, magicians and fortune tellers – -E.W. Dijkstra

In the past five years, I have come to think that it is valuable for the general public to know the distinction between a good computer system and a bad one, especially that the consequences affect even the innocent. Perhaps you have been to the bank and a teller casually announces that you can not withdraw or deposit money because the system is ‘down’, or you can not access your academic transcript because the system is ‘unavailable’. Maybe you have ever missed salary because of the computer system! Failure to withdraw your money may mean the landlord evicts you from the house or your son misses school. Failure to get the transcript may mean a missed life-time opportunity.

Such systems lead to wastage of millions of money, put lives at stake and businesses on the mercy of quarks. For government, the security of nation can be put at stake. The more computer systems fail, the more it becomes incurable because the general public has come to believe that it normal for systems to usually fail

A comparison with civil works

A comparison between the engineering of computer systems and civil engineering is informative. Unlike civil works, where the effects of a rudimentary engineering or lack of it are there to see through collapsing buildings, eroded fences and roadworks that are often fatal and lead to deaths, the effects of a rudimentary computer system are not readily visible. Mechanical engineers can get away with approximations for unknown or incalculable effects, substandard materials, and other surprises by building in safety margins. However, in software systems a single bit error can have disastrous consequences. Despite the the invisible nature of immeidate impacts of ill designed computer systems, the consequences  go beyond what most can predict and can be as fatal as a collapsing building with occupants.

Unlike civil works that may be faced with fake construction materials (such as cemment in Uganda), the key players in the construction of software systems are the programmers and those that buy the software. So the quality of the software is enitely in the hands of programmers.

Now warrant not guarantee -“as is”

 Interestingly, computer scientists mastered in advance, the art of hiding their incompetencies. They use fancy terms such as bugs to describe what ordinary means a malfunction. That is, a system that can not correctly do what it was intended to do. They do not even want to take responsibility of their own actions. Most software systems provide no guarantee or warrant for even the very mission the system is supposed to achieve.

The public has also accepted this situation and with not regret, it is not is common to hear  with a smile  that the computer system is not working, or the computer system is unavailable. Such lame explanations that have made system failure synonymous with the computing discipline are hurting. Such systems should not be casually accepted and need to be questioned for evidence of rigorous software engineering in the design and construction.

Good software is supposed to be reliable

Like any tool, a good software system is supposed to be reliable, that is safe to use by virtue of the fact that, when used, it acts as intended, or, more precisely, it reacts upon our inputs as intended. Even before subjecting a software system to a rigorous check for suitability of purpose, some indicator of incomplete and poor workmanship are usually there for even the computer illiterate to see. The first systems to be dismissed with contempt are those that fail due to any user inputs or limit existing good manual practices. That is, start by entering any data and good system should continue to behave normally. Bad systems will fail. Such systems are a clear manifestation of inept software engineering where the system is erected prematurely.

The buyer  at fault 

Executives, procurement officers should be aware that any programmer of some intelligence can cook up a computer system, the properties of which are utterly unattractive and unrelated to anything else. They need to be aware that the construction of computer systems is not a chaotic process with out systematic means to evaluate and sort them.

The executive managers with no formal training in software engineering approve these systems on the basis of their computer literacy normally in typing skills and email forwarding. Simple clicks and intelligent animations are usually enough to   append their signatures on products that are an art of ingenious and intelligent computer quarks.

Software production is a systematic process and quality can be assured

The most important aspect of a software-based system lie in the modeling and analysis of its interactions with external factors and overall mission assurance. Before purchasing or accepting to use a software system, it must be checked for for system-level information assurance issues. It must be checked for Possible fail-stop mechanisms and procedures, fallback, contingency solutions for both direct and secondary effects of failure modes. And Usage scenarios are frequently not a priori limited.

The regular failure and unavailability of computer systems has convinced the general public that it is normal for computer systems to fail. The proliferation of poor systems is a making of buyers who are easilty decieved by self made computer experts. As Edgar Dijkstra put it, Like any incurable disease it (software) attracts more quarks, magicians and fortune tellers

2,518 total views, no views today

Turning ‘software’ into a ‘software service’

This article looks at how to turn an  existing software that is not service oriented into a service that can be used in a service oriented architecture. We need to know  exactly-  what  is a service?  We are assuming the resulting service will provide  identical functionality. So the  only difference between a software service and other software components is at the interfaces. The interfaces define how the service can be used individually or as part of a larger system. In summary a service needs to achieve the following properties :-

  • is self contained, highly modular, and can be independently deployed. A service can do something useful in its own right.
  • is distributed component, accessible over the network or locator other than the absolute network address.
  • has a published interface, so users only need to see the interface and need not to know the internal details of the implementation.
  • is discoverable, meaning users can look it up in a special directory service where all the services are registered. Services designed for public use require to be discoverable, otherwise potential users may never learn about the service.
  • stresses inter-operability such that users and providers use different implementation languages and platforms. That is any software can be turned on a service for use with other services regardless of the languages in which they are implemented.
  • is dynamically bound, which signifies that the service is located and bound at runtime. Therefore service users do not need to have the service implementation at build time.

Therefore, turning  a software system into  a service consists of encapsulating the software such that it is  exposed  to the web via well defined and  flexible network accessible application programming interface (API).  This can only happen using a set of inter-related technologies. Currently web services provide a technology suite that can provide the above listed characteristics.

Our next article will relate the technologies in web service to   the properties of a service.

2,431 total views, 3 views today

Problem Solving – Analyse/Understand the Problem

The goal of problem analysis is to gain better understanding of the problem being solved before development begins. It is import to know why the problem is occurring, when and how often. Try to understand the first cause of the problem. Root cause analysis is a systematic way of uncovering the root, or underlying first cause of an identified problem or a symptom to the problem. Tools such as fishbone diagram or pareto chart can help visualize the problem.

Identify stakeholders – understand needs of users or other stakeholders. A stakeholder is anybody affected by the implementation of a new system or application. Probing questions include

    • who are the users of the system?
    •  who is the customer?
    • who else will be affected by the system?

Define a solution boundary- the solution boundary divides the world into two parts, your system and the rest of the things that interact with your system. The system boundary defines the border between the solution and the real world that surrounds the solution. A boundary is an interface between the system and the environment or other system. All interactions with the system occur via interfaces between the system and the external world.

Understand what is involved in solving the problem. This is involves a identifying what is information is needed and what information is available.

Identify constraints to be imposed on the system – a constraint is a restriction to the degrees of freedom we have in providing a solution. Constraints may be political, economical, environmental, technological, materials and resources as described below
Economical

  • What financial or budgetary constraints apply?
  • Are there costs of goods sold or any product pricing considerations?
  • Are there any licensing issues?

Politics

  • Do internal or external political issues affect potential solutions?
  • Are there any interdepartmental problems or issues?

Technology

  • Are we restricted in our choice of technologies?
  • Are we constrained to work within existing platforms or technologies?
  • Are we prohibited from using any new technologies?
  • Are we expected to use any purchased software packages?

Systems

  • Is the solution to be built on our existing systems?
  • Must we maintain compatibility with existing solutions?
  • What operating systems and environments must be supported?

Environment

  • Are there environmental or regulatory constraints?
  • Are there legal constraints?
  • What are the security requirements?
  • What other standards might restrict us?

Schedule and Resources

  • Is the schedule defined?
  • Are we restricted to existing resources?
  • Can we use outside labor?
  • Can we expand resources? Temporarily? Permanently?

3,579 total views, no views today

Problem solving -Define the problem

“Until the problem is well defined and articulated it is impossible to arrive at a solution”

The first step to solving any software engineering problem is to define the problem. Articulate the problem and eliminate all unnecessary terminologies and jargons. Start by reading the problem completely at least twice. Read and establish the context of each key word. If time allows, research about the problem.

Ensure that there is agreement on the problem to be solved. Try to restate the problem in you own understanding.  Find out from the person who posed the problem whether the restated problem is the same as the original problem. Identify instances of the problem and see it is possible to solve an instance or example problem A solution to the example problem may lead to insights about how to solve the general problem or bring about any remaining misunderstanding.

Look at the problem from multiple perspectives. Each perspective may reveal additional information about the problem. The problem should be distinguished from its symptoms such that the root cause properly identified and stated.

The output of this step is a well-defined and articulated problem that focuses on what is required for its solution.

1,606 total views, 2 views today

Software programming and problem solving

Programming is the process of planning a sequence of steps called instructions for the computer to follow. The fact that you are reading this post you already know that computers lack common sense and cannot make any judgment. So the computer will do as instructed by the programmer through the computer program. Programming is more about problem solving than coding.

A problem is the difference between things as perceived and things as desired. A solution will move the situation from the things as perceived to the things as desired.

Programmers are problem solvers and need to improve the art and science of problem solving. On one hand problem solving involves an element of art in that experience, judgment and common sense can help deliver smart solutions. On the other hand problems solving is a science involving scientific means of arriving at solutions. Overall, there are several steps to be taken to solve problems

  • Define the problem
  • Analyse the problem
  • List/Identify  alternative solutions
  • Select the best solution
  • List instructions that lead to the solution using the selected solution
  • Evaluate the solution

in the next post, more details on each step shall be discussed

1,433 total views, no views today