Chủ Nhật, 29 tháng 5, 2011

Move to new page

This blog marked my memorable time in my undergraduate school at Ho Chi Minh city University of Technology, Vietnam. During my undergrad, I concentrated mostly new and wonderful technologies, especially Sun's technologies.

Currently, I am a graduate student at Nation University of Singapore and I am pursuit my research in Parallel Computing, specifically Verification for Parallel Programs. Therefore, I have decided to completely move to my new blog at http://leduykhanh.blogspot.com/ which has more focus on what I am doing. The new blog serves as my knowledge archive and I hope that people in the Internet also find it helpful.

See you there ^_^

LDK

Thứ Ba, 12 tháng 1, 2010

What is Open Source

I read this article on Sun Microsystems websites which gives an good explanation of Open Source.
http://www.sun.com/emrkt/innercircle/newsletter/0110/sponsor.html?cid=e10088nf

Bob: Open source is often inappropriately used in the same context as freeware or shareware. Can you clarify what open source is and why it's important for CIOs and IT?

Simon: The term "open source" was first applied to software in 1998/1999 as part of the Open Source Initiative. During the preceding 20 years, the expression "free software" had been used to describe the same concept and, understandably, people were confused. They assumed free software must be defined by price, as in "free beer." Free software and open source software are best characterized by the set of freedoms that they offer. Open source software is free in the sense that it offers liberty. It's critical that CIOs focus on liberty rather than solely price. Liberty can save you money, but saving money doesn't necessarily give you liberty. Freeware and shareware are marketing mechanisms related to price rather than liberty.

Bob: You say open source is about liberty. I often refer to the same idea as low barriers to entry and exit. Is that a fair assessment?

Simon: Yes, that's fair. When I say liberty, I'm talking about a set of freedoms defined by [software freedom activist and computer programmer] Richard Stallman over the last 27 years. I characterize Stallman's freedoms this way:

  1. The freedom to use software for any purpose.
  2. The freedom to study software and understand how it works.
  3. The freedom to modify it to make it fit your purpose.
  4. The freedom to pass your modified version on to whomever you please.

Those four freedoms lie at the heart of the value proposition for CIOs — freedom to use the software for any purpose without having a relationship with any particular vendor. You may choose to have a relationship with a vendor later to service or modify the software, but it should be up to you to decide when to deploy and pay for service. The freedom to study the source code is freedom to access the market full of experts. The freedom to modify the source code means that the CIO is free to participate in the marketplace to get extensions, add-ons, and customized versions. And lastly, the freedom to pass it on to whomever you please means that anyone in the extended ecosystem can use the same software without barriers to rollout or licensing.

Thứ Hai, 30 tháng 11, 2009

IT salary survey

Long time no blogging ^_^ Don't want my blog with full of dust, today I decide to compose a new entry.
After reading the statistics from http://www.certmag.com/read.php?start=0&in=3915, I would like to have some notes

1) What we should study?

"Rounding out the top five highest-paying certs in 2009 were: (ISC)2 Information Systems Security Architecture Professional (CISSP-ISSAP) with $136,060; Brocade Certified SAN Manager (BCSM) with $136,020; Brocade Certified Fabric Designer (BCFD or BCSD) with $135,600; and the (ISC)2 Information Systems Security Management Professional (CISSP-ISSMP) with $134,100."

Obviously, I should be Security and Telecom ^_^


2) Should we study graduate schools?

"Another finding is that the majority of individuals in each of the other groups — including those with a high school diploma, a two-year associate’s degree, technical training, bachelor’s degree and master’s degree — reported annual earnings between $100,000 and $109,999 this year. These results are somewhat surprising given the vast difference in qualifications and skill sets that exists among these groups.

What has remained constant, however, is the fact that the majority of those who possess a doctorate command the highest annual salary among all groups — 11 percent of those with a doctorate reported earning between $110,000 and $119,999 this year."

If you have an PhD, you will have an increase of 11% in terms of salary. But reconsider about PhD. You spend 4-5 in graduate schools just to earn an increase of 11%. In terms of opportunity cost, PhD doesn't make sense.


3) If no PhD, what should we study?

"Trends such as “hybrid jobs,” which are positions that blend IT with expertise in another industry — health care, for example — require much more than simply an IT specialization. Often, they entail obtaining another degree in a different subject."


Having a non-IT degree + IT degree are the best. For example, MBA + IT Engineer Master is wonderful.

4) Is Web Development out of date?

"As for lower-salary-tier IT specializations on the slump, Web development seemed to continue its downward trend from last year, with about 17 percent of its respondents indicating that they earn less than $20,000."


The answer is YES.


5) How are developing countries's IT pros, especially Vietnam?

"Last year’s Salary Survey had Vietnam, Sri Lanka, India, the Philippines and Pakistan as its lowest performers in terms of salary — in that order. These countries had similarly low numbers this year, with 82.6 percent of respondents in the Philippines, 76 percent of respondents in Pakistan, 74.8 percent of respondents in India, 73.5 percent of respondents in Sri Lanka and 70.6 percent of respondents in Vietnam earning less than $20,000 a year."


Poor Vietnam, but it reflected that real situation in developing countries.


SUMMARY

BEST JOB: IT Security/Telecom Engineer Bachelor + MBA + Working in US or EU ^_^


Good luck ^_^

Thứ Tư, 5 tháng 8, 2009

Nested Parallel for and OpenMP compilers

Nested parallelism behavior depends on the implementation therefore it's different on different compilers.

For example with nested parallel for

#pragma omp for
for ( , , )
#pragma omp for
for ( , , )
foo();

On GNU compiler (gcc 4,3,3 for example), you will see the warning: "work-sharing region may not be closely nested inside of work-sharing, critical, ordered or master region".

However, on SunStudio 12, an error is thrown: " pragma for is not allowed to be nested inside of for".

Be careful and considerate when using nested parallel for.

GNU Feature Test Macros

Why do we usually specify #define _GNU_SOURCE in our source code?What does it actually mean? #define _GNU_SOURCE is a GNU Feature Test Macro. GNU Feature Test Macros enable extensions on glibc (GNU C Library). I helps the system to have more functionalities.

For more information, please have a look at http://www.gnu.org/s/libc/manual/html_node/Feature-Test-Macros.html

Thứ Năm, 30 tháng 7, 2009

Thứ Hai, 1 tháng 6, 2009

Celebrating the release of OpenSolaris 2009.06!

From http://www.opensolaris.org/jive/thre...start=0#382392

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Today marks the release of OpenSolaris 2009.06, the third release of the OpenSolaris Operating System.

We've shifted gear, bringing you a new set of features right to your door, from the desktop to the data center. For a complete list of what's new with this release, check out the OpenSolaris 2009.06 What's New Guide

http://www.opensolaris.com/learn/fea...ats-new/200906

OpenSolaris for SPARC is now available as part of this release, and will work on systems with an OBP level of 4.17 or greater. You can check out the required specifications at

http://www.opensolaris.com/learn/specifications/

along with the hardware compatibility list

http://www.sun.com/bigadmin/hcl/data/os/

Download Links:
=============
http://dlc.sun.com/osol/opensolaris/...l-0906-x86.iso LiveCD
x86/x64
http://dlc.sun.com/osol/opensolaris/...l-0906-x86.usb LiveUSB
x86/x64
http://dlc.sun.com/osol/opensolaris/...6-ai-sparc.iso
Automated Install SPARC
http://dlc.sun.com/osol/opensolaris/...906-ai-x86.iso
Automated Install x86/x64

http://dlc.sun.com/osol/opensolaris/...906-hashes.txt MD5
sum hashes

Release notes:
============
As always when installing the latest images, check out the release notes for both x86 and SPARC for any known issues

http://www.opensolaris.org/os/projec...es/200906/x86/
http://www.opensolaris.org/os/projec.../200906/sparc/

How to update:
============
Upgrading from OpenSolaris 2008.11 (or any previous releases) is easy using the Package Manager or pkg(1) command line. Check out a screencast of how to upgrade

http://webcast-west.sun.com/interact...123/index.html


Thanks are due to a large number of people who've helped contribute different projects to this release, both within the OpenSolaris community itself and the wider free and open source world. We'll be celebrating at CommunityOne with a great line up of OpenSolaris content - if you happen to be in the area, please join us and help us celebrate this release!

http://www.opensolaris.com/communityone/

Enjoy!
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