Thursday, November 02, 2006

Lean Software Development according to Poppendieck

To create a Lead process, waste should be eliminated.

Taking this approach to software development (from requirements to deployments) helps explain many of the project failures I have saw or heard about.

In software development, the following are considered waste:

1. Partially Done Work
This is hard to first see, but a module that 'almost' works (but then abandoned for months) has very little value. So is a module that is so-called complete, but is untested, and therefore the bug-fixing work is not done.
This is similar to 'inventory' in classic lean; there is a high cost in having partially-done software (the knowledge gets obsolete, APIs and other systems shift, etc) which is not obvious to management.
Also, if it isn't deployed now, there is a chance that it would never be deployed.

2. Extra process
Clearly, stacks of paper have no positive impact except whatever benefit they did to the shipping code.

3. Extra features
Any additional line of code, and every additional feature, adds system complexity. Fixing a bug would now cost more; adding other (important) features would take longer. Carrying 500 pounds of dead weight in your car is only going to slow you down, and so are deadweight features

4. Task Switching
Every time a developer has to perform multiple tasks, they all take longer, and focus is lost.

5. Waiting
Having to wait (for approval, feedback, etc) slows the project down and wastes time

6. Motion
Especially in document handoffs, when every time a document is passed to the next person, knowledge is lost.

7. Defects
Bugs slow the process down since they require fixing, testing, and can cause other types of slowdown (such as causing developers to lose focus on their new features). Buggy code takes longer to complete.

Friday, October 27, 2006

Lean Software Development

Wikipedia states that "Lean Software Development is a translation of lean manufacturing principles and practices to the software development domain."

Lean software development, to me, is best viewed as both the philosophical underpinning of Agile, and as the extension of a similar approach to the entire software 'production' chain, from conception, through approval, to deployment.

The main points that a developer or a program manager would find helpful are:
* System: Optimize the system, not each part separately
* Value: understand what creates value for your customer, and how your organization creates value
* Flow: Maximizing speed minimizes wastes
This one is hard to see at first. But delivering a functioning solution earlier is critical since:
- You are producing the solution since it has value to the customer. The sooner the customer uses a functioning system, the more time he gets the benefit for, so the higher his total benefit is. If the core systems would save the customer $100k a month, delivering a core system 3 months later just cost $300k
- The time it takes to initiate and approve a project counts as cost, too. That stack of 'waiting for approval' projects on the VP's desk is costing the organization, the same way that the queue of people waiting for service in the grocery store costs you time.
- The more 'outstanding' projects there are, the more multitasking people need to do. Multitasking is expensive and inefficient.
- The more time passes, the less knowledge is fresh. Knowledge is what software development is all about.
* Pull: Deliver value based on customer (or next-in-production-chain) needs
And the perfect bad example is when the test organization is months behind the developers in testing. The dev team might be code-complete, but the product won't be shipping for six more months...

Special thanks to Alan Shalloway and his Lean presentation. The errors, of course, are all mine.

Thursday, July 13, 2006

12 Basic Principles of Design For Perfomance

Goals and measurement:

1. Set performance goals
2. Set a performance 'budget' (e.g. 300ms for update etc)
3. Define performance testcases


4. Understand resources - disk, memory, network bandwidth, database connections, and local data protected by locks
5. Cut the deadwood - especially when reusing existing services and components, make sure your code doesn't do more (create more results, processes more data) than is needed.
6. Batch work - this will minimize roundtrips and enable efficiency gains from accessing resources only once.
7. Pool shared resources - such as database connections, TCP connections, or anything which has setup and teardown costs
8. Process independent tasks concurrently
9. Consider affinity - put resources near where they will be used; duplicate readonly resources (trade-off storage/memory for access time)
10. Use caching; design appropriate cache policy
11. Consider the efficiency of your algorithms; prototype algorithms early
12. Identify bottlenecks; there is always one more bottleneck

Sunday, May 14, 2006

Programming languages popularity trends

This information is based on Google Trends (, which compares number of queries for a keyword
comparing the keywords C# and Java, Java queries are more popular by trend downwards, while C# queries trend upwards. Similar results come from comparing the keywords "c# source" and "java source", "c# programming" and "java programming"

Saturday, January 21, 2006

Programming languages popularity

Trying to measure programming languages popularity is hard.
In an earlier post, I measured the number of the availability of jobs based on and similar places. Another interesting article is here. Both analysis supprt the view that C# and .NET jobs constitute the leading section of the job market, and more non-scientific research leads me to believe that .NET constitutes a majority of the NEW (as opposed to legacy, or code maintnance) programming jobs.

What do you think? I am looking for feedback, or your own experience.

Monday, January 02, 2006

telnet rules

A fact often missed by people too-used to web sites is that most services on the internet have underlying protocols. For example, if I want to do internic search on a domain name, I could google for a service that does just that; but I can just as easily get the information myself from port 43 of

telnet 43
and you get (truncated):
Domain Name: BLOGGER.COM
Whois Server:
Referral URL:
Name Server: NS2.GOOGLE.COM
Name Server: NS1.GOOGLE.COM
Name Server: NS3.GOOGLE.COM
Name Server: NS4.GOOGLE.COM
Updated Date: 22-jul-2005
Creation Date: 22-jun-1999
Expiration Date: 22-jun-2011

now, wasn't this easy?

.NET jobs exceed Java jobs

With the release of Visual Studio 2005 and the growing popularity and maturity of .NET, it seems more and more businesses are looking for .NET developers, as opposed to Java developers. Java popularity also suffers from competition from other Open Source languages and platforms such as Perl and Ruby (on rails).

For example, a quick search [Jan/2/06] on for .NET for '.NET' finds 9444 positions; 'Java' returns 2635.
Note that a search for 'C#' only returns 797 positions; .NET is by far a stronger brand name than C#, and the '#' sign wreaks havoc with multiple search engines.

Similar nationwide searches in read
Java : 6126
.Net : 10871
C# : # not supported in yahoo search

XML is also becoming a strong requirement:
XML ( 3396
XML (Dice): 6949

Tags: jobs .net java software market