Common Sense 4 Common People

The Law of Late Projects

Very recently a good friend of mine, Prof.Vasilis Vassalos, made a comment on Facebook about Parkinson's law by referring to this article.

Parkinson's law says that all work expands to fill all time available for its completion.

This has be proven statistically to be very true, so nobody can doubt it. However some of the consequences of this law often go unnoticed as the law's wording and meaning gets twisted and turned over to suit one's needs.

FireWire 1.6 Gbps and 3.2 Gbps announced by DAP Technology!

Last week I told you about the forthcoming news on 1.6 Gbps and 3.2 Gbps FireWire.

Now, here is the official press release from DAP Technology!!!

Have fun!
Dimitris Staikos

FireWire moving forward

Two weeks ago I visited the Vision Show 2009 exhibition in Stuttgart, Germany.

Two very important things happened there with regards to FireWire (IEEE 1394) technology.

1. DAP Technology made a demo of their S1600/S3200 solution. That's 1.6Gbps and 3.2Gbps respectively. It worked fine over 10m standard FireWire cables.
   The demo was semi-public and DAP will make a relevant press release within the next days.
2. Two companies demonstrated their S800-over-Coax cable solutions, using the S800 coax transceivers of Eqcologic.

They are both great news for FireWire, because they show that FireWire is still moving forward.

Have Fun!
Dimitris

Rules of program optimization

I recently watched a recorded presentation of Prof.Diomidis Spinellis, author of a couple of world famous books on programming, like "Code Quality". At some point Mr.Spinellis discussed the issue of program optimization and mentioned some famous quotes related to this issue, quotes that were also listed in his "Code Quality" book:

• The First Rule of Program Optimization: Don't do it.
• The Second Rule of Program Optimization (for experts only): Don't do it yet.

These come from M.A.Jackson. It is hard to exaggerate how much I agree.

I would like to add my own rules to the list :-) Maybe others have said similar words, but now I copy from my own brain:

• The 3rd Rule of Program Optimization: Make sense of it in the real world first.
• The 4th Rule of Program Optimization: Measure it and justify it before you commit to it.

Programmers often set sail to optimize a piece of code, just because it is plain for all to see that this piece of code CAN be optimized. However, you should do some serious thinking first to see whether it makes sense to optimize this piece of code. How often is it run, under which paths, how long does it take to execute, etc. For example don't optimize code to turn a 0.1 msec into a 0.01 msec if that runs once every minute.

Does it make sense to optimize a process that is executed once a day, if that process takes 10min, 20min, 120min, 360min? Would it make sense to optimize the 10min to 1min (10/1 improvement), the 120min to 30min (4/1 improvement) or the 360min to 120min (3/1)?

You definitely can't tell the answer by looking at the numbers. Maybe the 360min procedure runs at the end of the day, after all employees are gone, so no one benefits from the improved performance, but then the backups can be scheduled earlier. Or the 120min process runs over lunch break, so having it finished before people return from lunch does not make that much of a difference.

That's the meaning of the 3rd rule, don't look at the code searching for optimizations, look at the real world for optimizations.

The 4th rule is a bit drastic. After you decided to optimize the code, do some measurements. Careful measurements of the old implementation, careful measurements of the new implementation. If the improvement is NOT worth the while, then you might as well scrap the optimization. Throw it away. You thought you had good reason, you made extensive changes but didn't get the improvement you expected; no hurt feelings, just dump it.

Code complexity and maintainability are far more critically important than a minor performance optimization. KISS should be the topmost priority, not writing code that makes programmers feel good about themselves ;-)

Have Fun!

Dimitrios Staikos

The Internet says...

Today I was walking the streets of downtown Stuttgart in Germany and of all things possible, I was looking for a post office. I was given some directions by some friendly local, but I still couldn't find it. So I asked another passerby for assistance.

He didn't know, but he immediately popped out his cell phone and told me "Let me check on the Internet". I don't know why, but I felt that this event transitioned me into a whole new era. Most likely because it was the first time in my life that a completely random passerby would access the Internet in order to offer me the assistance I was looking for.

What amazed me even more was the way he formulated his reply soon after:

"The Internet says it's on Marienstrasse 19".

Have Fun!
Dimitris Staikos

PS: Beware of what the Internet says... The post office wasn't there ;-)