Dr. Volkan Tunalı's Personal Blog

Computer, Technology, Science, Art

NoSQL Revolution (and Evolution)

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Revolutions are endemic to tech culture. A new group comes along and wonders why the last generation built something so complex, and they set out to tear down the old institutions. After a bit, they begin to realize why all of the old institutions were so complex, and they start implementing the features once again.

We’re seeing this in the NoSQL world, as some of the projects start adding back things that look like transactions, schemas, and standards. This is the nature of progress. We tear things down only to build them back again. NoSQL is finished with the first phase of the revolution and now it’s time for the second one.

I’ve read an interesting article about NoSQL databases at infoworld. The article explains how the revolution of NoSQL databases have emerged and what the current situation from the perspective of solution development is. I think the article touches on important issues where NoSQL databases have inherent weaknesses besides their advantages, and every solution architect or developer must be aware of those issues.

To read the full article, please follow this link: 7 hard truths about the NoSQL revolution.

Written by Volkan TUNALI

July 16th, 2012 at 4:34 pm

Cryptography Classes for .NET Compact Framework

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You may know that System.Security.Cryptography for Compact Framework lacks many cryptography algorithms compared to the desktop .Net Framework (2005 and later). In a project we have needed SHA512 encryption on Windows CE and we have found /cfAes library which provides almost all of the crypto functionality of .NET Framework. We are grateful to the author for sharing the class library.

The following table displays a comparison between the versions of .Net Framework with respect to the support for different crypyography algorithms (X means that it is supported, 0 means partially supported).

Crytpo Algorithm .NET 2003 OpenNETCF 1.2 /cfAES WSE 2.0 CF 2.0 .NET 2005
MD5 X X X X X
SHA1 X X X X X
SHA256 X X X
SHA384 X X X
SHA512 X X X
MACTripleDES X 0 X X
HMACSHA1 X X X X X
PasswordDeriveBytes X 0 X X
RC2 X X X X X
DES X X X X X
TripleDES X X X X X X
Rijndeal X X X X
RSA X X X X X X
DSA X X X X X
RIPEMD160 X X
HMACMD5 X X
HMACSHA256 X X
HMACSHA384 X X
HMACSHA512 X X
HMACRIPEMD160 X X
Rfc2898DeriveBytes X X
ProtectedData X X
ProtectedMemory X X
PSHA1 X X
AESKeyExchangeFormatter X X
TripleDesKeyExchangeFormatter X X
SecureString X X



You can download the source code of the library here.

Written by Volkan TUNALI

November 10th, 2010 at 11:56 am

Storage Cost over Years

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Every time I buy a new PC, either desktop or notebook, its hard disk capacity is larger than the previous one even though the total price of the PC is about equal. The same thing may apply for the other components of the PC like main memory capacity and CPU power, but hard disk capacity is something very different.

Matthew Komorowski has collected hard drive capacity/price data and created the graph below:

Storage cost over years
Source: http://www.mkomo.com/cost-per-gigabyte

Komorowski has also drawn a conclusion about the capacity/cost trend as:

Over the last 30 years, space per unit cost has doubled roughly every 14 months (increasing by an order of magnitude every 48 months)

Moreover, he has a formula for the cost as

cost = 10-0.2502(year-1980)+6.304

Below are two pictures from computer magazines of 80s. Incredible!

Written by Volkan TUNALI

September 18th, 2010 at 12:24 pm

Quote of the Day from Antoine de Saint-Exupéry

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Saint ExuperyHere comes the quote of the day from Antoine de Saint-Exupéry who is best remembered for his novella The Little Prince (Le Petit Prince):

Perfection is achieved not when there is nothing left to add, but when there is nothing left to take away.

- Antoine de Saint-Exupéry

I like this saying because it emphasizes that simple and effective approaches should be sought to design and build anything (eg. software producsts in my profession) elegant.

Written by Volkan TUNALI

September 17th, 2010 at 3:09 pm

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Hottest Majors for Future Career According to Microsoft

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careerThere is a blog article published recently at Microsoft JobsBlog which talks about the hottest fields of study for a career in technology. All these three hottest majors mentioned are data mining related. The list is as follows:

  • Data Mining/Machine Learning/AI/Natural Language Processing
  • Business Intelligence/Competitive Intelligence
  • Analytics/Statistics – specifically Web Analytics, A/B Testing and statistical analysis

The article concludes as:

These fields are very HOT and looking long term, the demand will be just that much greater in these areas.

You can read the full article at http://jobsblog.com/blog/top-three-new-tech-majors/.

Written by Volkan TUNALI

August 26th, 2010 at 8:48 pm