My Tech notes

Motorola EX128 | Motorola India | Motorola EX115

noreply@blogger.com (balasaheb) — Fri, 01 Oct 2010 05:45:00 +0000

Motorola EX128 | Motorola India | Motorola EX115

Motorola India has also launched another Dual SIM touchscreen handset in India namely Motorola EX128. Motorola EX128 comes with a 3.2 inch WQVGA touchscreen display with 240x 400 pixels resolution, 3 megapixel fixed focus camera, music player, video player, video recorder and expandable memory.

Motorola EX128 also features EDGE, GPRS, GSM connectivity, Bluetooth, social messaging, Email and 910 mAh battery for talktime of 200 mins. It is available in steel gray color.
Motorola EX128 Price

Additional Key Specifications of both the MOTOROLA EX128 & EX115:

Supports various audio formats: MP3, AAC, AAC+, MIDI, WAV. AMR NB
Supports MPEG4, that makes soundtracks come alive with the music player
Messaging: SMS, MMS, EMAIL (POP3, IMAP) 1
A standard 3.5mm audio jack to enhance the multimedia experience
FM radio
Bluetooth A2DP2
Expandable memory up to 32GB3 on microSD card
Supports Quad bands1 850/ 900/ 1800 /1900; GSM/EDGE (Class10) 1

Motorola EX128 , Motorola EX115 Availability

Both, the Motorola EX128 and EX115 are available at retails outlets in India.
The Motorola EX128 is priced at a Best Buy price4 of Rs 5,990 (MRP: Rs 6,990) and the Motorola EX115 is priced at a Best Buy price4 of Rs 4,990 (MRP: Rs 5,990).

Motorola EX128 is available for Rs 5,990 (MRP: Rs 6990) in India.

Mastering Iptable Command Line Usage Linux Networking

noreply@blogger.com (Bhagwat) — Sat, 07 Nov 2009 13:30:00 +0000

Some of the most useful commands related to iptable,

To display filter table rules.

#iptables -t filter -L

To display nat table rules.

To display raw table rules

To display mangle table rules.

Port forwading
# iptables -t nat -A PREROUTING -i eth0 -d --dport -j DNAT --to
The above rule will change the destinationIP:portnumber of the incoming packet to private.IP:portnum
Enabing the packet forward in the kernel with proc entry.
#echo 1 > /proc/sys/net/ipv4/ip_forward

iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables as a special for Ethernet frames.

source

Dotnet, .Net 3.5, 2.0, C# Interview Questions

noreply@blogger.com (Bhagwat) — Sat, 24 Oct 2009 11:36:00 +0000

Few questions on dotnet, C# 2.0, 3.5
On Object oriented concepts

1)What is inheritance with e.g
2)What is polymorphism
-function overloading
-Function overriding
-virtual keyword use
-Static keyword and use
-Abstract classes
-Interface
-Object

3)What is threading and how do we use in realtime application(cognizant)
4)What is threadpooling, lock, monitor(write code sample)
5)Architecture of current project
6)Session state, diffrent types of state management.
7)What is Application_Start, how it works.
8)Type of authentication in asp.net
9)How to configure ASP.NET application.
10) What is Impersonation.
11) What is WebService, WSDL, UDDI, Discovery, asmx files.
12) How to implement WebService and use it.
13) When to use WebServices.
14) WPF, how to implement(BOA)
15) Testing concvepts.
16) Test attributes
17) Flow of Automation Test Method execution
18) Features of dotnet 3.5
19) CLR, garbage collection
20) Finally block
21) Manifest, Metadata, MSIL
22) Assemblies, Type of assemblies, strong name
23) GAC, gacutil, shared assemblies, path of GAC
24) Extended properties, propertyInfo
25) Better choice between WinForm and WPF
26) XAML, primitive
27) C# 3.0 features

Many are their will keep updating

Answers will be provided as per the need. Please feel free to query.

Tags: OOP, C#, framewrok, Dotnet, .Net, 2.0, 3.0, 3.5

Virtual Table *_vptr , VTBL, C++

noreply@blogger.com (Bhagwat) — Thu, 22 Oct 2009 18:21:00 +0000

VTBL or VPTR nothing but virtual table and virtual pointer in C++.

It gets created when we create function with virtual keyword. As soon as we create the virtual function in a class A table gets created behind the code.

BaseClass
{
virtual void function1(){...}
}

ChildClass : public BaseClass
{
virtual void function1(){...}// method overridden.
}

When we override method that is create another version of function in derived class ChildClass in above case then the *_vptrvirtual void function1(){...}// method overridden. gets created for BaseClass.

So VTBL Of Base Class has entry for function1 and Child class will be pointing to that function. *_vptr is nothing but the pointer to function.

Note: ones the virtual keyword is introduced all the upcoming functions are considered as virtual.

ChildClass: public BaseClass
{
virtual void function1(){...}// method overridden.
void function2(){}
}

In above case function2 also considered as virtual.

BaseClass will not be pointing to any of Child Class functions and ChildClass will be pointing to all the virtual functions whose entry is in VTBL of baseclass as soon as the object of the base class instantiated or the method is overridden.

Tags : pointer, virtual, C++, function pointer,VTBL, VPTR, Function overriding , polymorphism

How to unzip .torrent files on Windows PC?

noreply@blogger.com (Bhagwat) — Tue, 15 Sep 2009 07:16:00 +0000

how to unzip .torrent files?
You do not need to decompress .torrent files. The .torrent will disappear from the end of the file once the file has finished downloading onto your computer.

Then you can use the file as you see fit. It may be a .mp3 file, a .zip file, etc
to use bittorent, you need a client. then open the .torrent file in azureus and you will download the file that the torrent is for. the .torrent isnt the file itself, it just tells the client where to get the file.
Here are some popular torrent clients for windows.
Download Azureus at Azureus
Azureus - now called Vuze - Bittorrent Client

Requires Java for Windows; if you are first time installing
http://java.com/en/download/inc/windows_new_xpi.jsp

Few more popular bittorrent clients for windows

Check out Comparison of BitTorrent clients - from Wikipedia, the free encyclopedia
BitTorrent is the name of a peer-to-peer (P2P) file distribution protocol, and is the name of a free software implementation of that protocol.

Creating & Working On a CVS Branch Example Usage

noreply@blogger.com (Bhagwat) — Fri, 21 Aug 2009 13:20:00 +0000

Example usage OF Creating & Working On a CVS Branch

Tried working hard on CVs commands, here is simple example for working in branch using CVS, CVS is becoming nomore use with everyone opting for SVN, still CVS usages is wide as it is old,
Lets start with CVS commands to create a branch
This is done with two commands,

cvs tag -b release-1 //create branch
cvs update -j release-1 //merge the changes in main tot

Lets see with simple example
Creating and working on a branch for the existing kernel source.
#cvs co kernel/linux-2.6.26
#cd kernel/linux-2.6.26/
#cvs tag -b release-1

First we created a branch to the kernel source, as we are doing first release.
Continue your development work for second release.
After some time, reported a problem in the first release.
So you need to Get the kernel source code of first release.
#cvs co -r release-1 kernel/linux-2.6.24
and fix the problems
Now If you want to merge these changes in to main trunk.
#cvs update -j release-1
And you are done with usage OF Creating & Working On a CVS Branch

Linux SMB write performance With Simple Tips

noreply@blogger.com (Bhagwat) — Wed, 12 Aug 2009 06:19:00 +0000

SMB write performance can be increased by Tuning the buffer cache.
The secret to good performance is to keep as much of the data in memory for as long as is possible. Writing to the disk is the slowest part of any filesystem. If you know that the filesystem will be heavily used, then you can tune this process for Linux Samba.

writing out dirty blocks to the disk until the filesystem buffer cache is 80 percent full (80). default is 40%, source = http://tldp.org/LDP/solrhe/Securing-Optimizing-Linux-RH-Edition-v1.3/chap29sec287.html

by writing
echo 80 > /proc/sys/vm/dirty_ratio

I am getting around 2MB increase while write operation, tested in Xp.

I have tried with this single option, as the ref source is for linux 2.2 and we are using 2.6 kernel.
we can try out Linux General Optimization suggested at http://tldp.org/LDP/solrhe/Securing-Optimizing-Linux-RH-Edition-v1.3/gen-optim.html

Tried with smb.conf, I am getting around 1MB gain while read and write.

socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE
oplocks = yes
dead time = 15
read size = 32768

TCP socket options can be tested at run time using -O option of SMBD
/usr/local/samba/bin/smbd -O socket optios = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE

source.
http://us1.samba.org/samba/docs/man/Samba3-HOWTO/speed.html

socket level perf improvement also suggests for TCP_NODELAY
ref: http://www.ibm.com/developerworks/linux/library/l-hisock.html

http://www.stuartcheshire.org/papers/NagleDelayedAck/

SAMBA perf tuning ref.

http://oreilly.com/catalog/samba/chapter/book/appb.pdf

CROSS COMPILING X11 FOR ARM Board

noreply@blogger.com (Bhagwat) — Wed, 29 Jul 2009 08:57:00 +0000

STEPS FOR CROSS COMPILING X11 FOR ARM
Go to /usr/X11R6/lib in my linux PC.

1) install ARM toolchain, If not installed
2) Get x11 source from http://www.x.org/
3) extract all the tar files, using tar -xvzf
4) edit cross.def and host.def files, in cross.def set the paths
of tool chain in host.def file set crossCompile to YES and
DoLoadableServer to NO
5) make shadow directory "build" and link to xc "lndir ../xc"
6) run Make World

error: linux_vm86.c 281 impossible constraint in 'asm'
268 res might be used uninitialized in this function.
fix:comment line 281,
set res=0

error: implicit decleration of function 'SET_FLAG'
fix: comment line 111 in
programs/Xserver/hw/xfree86/os-support/linux/int10/helper_exec.c

error:Undefined reference to XF86VidModeQueryVersion in glxinfo
And glxgears
Undefined reference to XF86VidModeQueryVersion in xdriinfo
fix:download libXxf86vm.so.1.0 into our armtoolchain lib path
and make softlinks

ln -s libXxf86vm.so.1.0 libXxf86vm.so
ln -s libXxf86vm.so.1.0 libXxf86vm.so.1

error:X_cursor.cfg command not found.
fix:

copied all the binaries from cvs in our
arm-tools-chain bin folder...didnt work

copied libXcursor.so.1.0.2 from cvs in our arm-tools-chain
and made links

ln -s libXcursor.so.1.0.2 libXcursor.so.1
ln -s libXcursor.so.1.0.2 libXcursor.so
...still didnt work

copied xcursor.pc in pkgconfig of toolchain.

looks like xcursorgen is missing .
got it from debian.still didnt work.

copied xcursorgen from programs/xcursorgen/ to tool chain
still didnt work.

export XCURSORGEN=/usr/X11R6/bin/xcursorgen
!!! WORKED !!!

Total compilation time with "Make World" is 20 minutes.

after compilation it prints a message:
"Full build of Release 6.8 complete."

error: while doing make install got the error in fonts:
"/bin/sh -b: command not found"

workaround:
removed "models" folder from Makefile at
"programs/Xserver/XpConfig/C/print/Makefile
fix:Open the makefile in Xserver/XpConfig/C/print/models/XXX/fonts/Makefile
and then set MKFONTSCALE=$(XBINDIR)/mkfontscale below XBINDIR on line
no around 389.

Define:Blu-ray & About Blu-ray Movies HDTV Info

noreply@blogger.com (Bhagwat) — Thu, 23 Jul 2009 06:46:00 +0000

The Advancement of technology had entered into nanometer age. search in google define:Blue-ray will get wiki pages here is summary of it. Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage medium designed to supersede the standard DVD format. Its main uses are for storing PlayStation 3 games, high-definition video, and data storage, with up to 50 GB per disc. This is quite impressive, The disc has the same physical dimensions as standard DVDs and CDs.
Why Blu-ray disc stores 50GB on same size of DVD/CD?
Well here is advancement of laser technology, thanks to Shuji Nakamura for his invention on blue laser,
The name Blu-ray Disc derives from the blue-violet laser used to read the disc. While a standard DVD uses a 650 nanometre red laser, Blu-ray uses a shorter wavelength, a 405 nm blue-violet laser, and allows for almost six times more data storage than on a DVD.
check out about
Blu-ray Movies - Everything about Blu-ray movies and releases.at http://www.blu-ray.com/movies/
Few interesting stuff from Blu-ray FAQ
How much data can you fit on a Blu-ray disc?
A single-layer disc can hold 25GB.
A dual-layer disc can hold 50GB.
How much video can you fit on a Blu-ray disc?
Over 9 hours of high-definition (HD) video on a 50GB disc.
About 23 hours of standard-definition (SD) video on a 50GB disc.
Why should I upgrade from DVD to Blu-ray?
The simple answer is HDTV.
visit http://www.blu-ray.com

Get HyperSCSI for SAN - Storage Area Network

noreply@blogger.com (Bhagwat) — Tue, 21 Jul 2009 11:36:00 +0000

Get HyperSCSI for SAN - Storage Area Network
SCSI (Small Computer Systems Interface) family of protocols. HyperSCSI can allow one to connect to and use SCSI and SCSI-based devices (like IDE, USB, Fibre Channel) over a network as if it was directly attached locally.
Why HyperSCSI over iSCSI?
The main advantage of HSCSI compared to iSCSI is

especially a lower network load as well as an end system (server and client) load.
TCP/IP SAN performance is still not good enough without hardware acceleration
FC-based SANs cannot do Storage Wide-Area Networks
Fully functional software implementation of both client and server so HSCSI can be used for a solution built on commonly available hardware, no expensive and specialized hardware is needed.
Therefore, HSCSI can be used for building small and cheap SANs.

HSCSI main disadvantage is this protocol has no official standard like iSCSI nd so it is unsupported in any way by manufacturers developing hardware data storage solutions.
Two modes of operation
one for local access,Local HyperSCSI over Ethernet (HS/eth),
and the other for wide-area connectivity, Wide-Area HyperSCSI over IP (HS/IP).
The reason why I am posting this is, I could not able to locate source code for HyperSCSI easily.
HyperSCSI source code download link for linux
download links
http://www.dsi.a-star.edu.sg/main/dev/mainPage.asp?cid=15022&Lid=0

Will post more if get luck while compiling HyperSCSI for ARM target board.

The things must know about Linux kernel ...

noreply@blogger.com (Kernel Ticks) — Wed, 15 Jul 2009 07:21:00 +0000

As a kernel or device driver developer one must know what Linux kernel can not

1) No access to C library
Generally, C library is large. Accessing a C lib function from kernel space is very time consuming.
It affects the kernel speed and size. So many libc functions are implemented in the kernel. Just like printf in libc is implemented as printk in kernel.

2) The kernel lacks memory protection.
Application in user space lacks memory protection. so when an application access illegal memory location, it results in segment violation. But when in kernel space segment violation occures, it results in oops. It is a major kernel error.

3) Difficult to use floating point.
When floating point arithmetic is done in user space, kernel manages the transition from integer to floating point mode. But enabling floating point in kernel, the kernel requires manually saving and restoring the floating point register. It is extra overhead for kernel.

4) Limited and small stack
Linux kernel has very small stack size. The size varies by architectures. Generally it is 8KB for 32-bit architecture and 16KB for 64-bit architecture.

5) Requires synchronization and concurrency
Linux kernel is a preemptive multitasking operating system. So scheduler schedules any process among the pool of processes. It requires synchronization between tasks. The concurrency is required when two or more processes tries to access the same resource.

Linux Kernel Based Chrome OS : Google

noreply@blogger.com (Kernel Ticks) — Sun, 12 Jul 2009 08:27:00 +0000

Google Chrome OS is an open source, lightweight operating system. It is designed mainly considering netbooks. The notebooks will be available to consumers in mid 2010.
This will be an open challenge to its rival MS Window. The key aspects of Google Chrome OS are its security, simplicity and speed.

What is difference between monolithic kernel and microkernel?

noreply@blogger.com (Kernel Ticks) — Sat, 11 Jul 2009 08:19:00 +0000

Monolithic kernel has simple design. Monolithic kernel is a single large processes running entirely in a single address space. It is a single static binariy file. All kernel services exist and execute in kernel address space. The kernel can invoke functions directly. The examples of monolithic kernel based OSs are Linux, Unix.

In Microkernels, the kernel is broken down into separate processes, known as servers. Some of the servers run in kernel space and some run in user-space. All servers are kept separate and run in different address spaces.The communication in microkernels is done via message passing. The servers communicate through IPC (Interprocess Communication). Servers invoke "services" from each other by sending messages. The separation has advantage that if one server fails other server can still work efficiently. The example of microkernel based OS are Mac OS X and Windows NT.

Create File Of Any Size in Linux Using DD Command

noreply@blogger.com (Bhagwat) — Wed, 10 Jun 2009 08:16:00 +0000

How do I create a file of any given size on Linux?
using the dd command.

$ dd if=/dev/zero of=testss bs=1024 count=1048576

This will create a file of size 1024 * 1048576 bytes (or 1 GB).
where
if - input file
of - output file or the file to be created
bs - block size in bytes
count - # of blocks of size bs

Easiest and fasted way to create file of 250GB using DD command

$ dd if=/dev/zero of=tests bs=1 count=0 seek=250G

read dd(1) - Linux man page

Xilinx's Interview Questions

noreply@blogger.com (Kernel Ticks) — Fri, 05 Jun 2009 16:36:00 +0000

Xilinx is the world's one of largest supplier of programmable logic devices. It has started R & D department in Hyderabad, India. It has broad scope for embedded system programming in device driver in linux.

Before the interview you have to feel the Xilinx form with information containing all academic details, current/previous employer, contacts of employer( to check out info about you), current ctc, expected ctc and expected date of joining, etc.

I appeared two back to back technical interviews.

The first interview was taken by a young man look like just crossed 30's.

He asked me to tell me about myself.

Then he asked my experience.

He checked my expertise in resume.

He asked questions about RTOS, and Linux Device Drivers.
What is RTOS ? Define it.
How a linux device driver works?
How a character driver works?

He looked at my project summaries and started to ask in depth questions about each project.

After that he asked me to write to delete nth node from starting in Singly Linked List.
Then asked how would you delete the nth node from ending?

Then he asked to set and reset the nth bit of a byte.

After the first interview the second interview was unexpected for me.
This second interview was taken by a lady in mid 40's.

She asked me about why I chose embedded system as my carriar instead of the post graduation.

She had copy of my resume with her and noted down on resume years when I compledted graduation and diploma.

She asked me my expertise in embedded system.

Then she offered me to choose any of my projects which I did in my previous company and explore about them.

She started grilling on each and every, sentence and words about that project.

At the end she asked me to write a string reversing program as she gave some intial start of the code as

char * strrev( const char * string){

}

So these are some technical questions were asked me in Xilinx interview.

SCALA Programming Language Secret Behind Twitter's Growth

noreply@blogger.com (Bhagwat) — Fri, 05 Jun 2009 11:27:00 +0000

SCALA programming language and Secret behind Twitter's growth
Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages, enabling Java and other programmers to be more productive. Code sizes are typically reduced by a factor of two to three when compared to an equivalent Java application.
http://www.scala-lang.org/

Introducing Scala

Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages, enabling Java and other programmers to be more productive. Code sizes are typically reduced by a factor of two to three when compared to an equivalent Java application.

Programming Scala book

Programming in Scala Some books

A comprehensive step-by-step guide
by Martin Odersky, Lex Spoon, and Bill Venners
Book ToC at
http://www.artima.com/shop/programming_in_scala
Sample chapters from SCALA book
A scalable language http://www.artima.com/samples/chapter1.pdf
First steps in Scala http://www.artima.com/samples/chapter2.pdf

Secret behind Twitter's growth

Scala programming language helped Twitter scale
http://www.technologyreview.com/blog/editors/23282/?nlid=1908
Also do visit slides of the Scala talk given at Twitter headquarters.
http://www.slideshare.net/raffikrikorian/scala-wattzon-sitting-in-a-tree

Debugging Defined Testing DOTNET

noreply@blogger.com (Bhagwat) — Tue, 02 Jun 2009 09:17:00 +0000

Tags: Debugging, Testing, DOTNET, windows

apsscresults 10th Class results ssc 2009 of AP Board

noreply@blogger.com (Bhagwat) — Wed, 27 May 2009 08:11:00 +0000

Andhra Pradesh State Board SSC Results 2009 announced today (27-May-09) by 10.45 am. There is lot of rush for those sites, Results will be available on the following sites: I have tried to give direct links for results, good luck to students.

Results direct links from manabadi ssc
SSC results on SMS from manabadi

Results direct links from results.sakshi.com

AP SSC REGULAR results 09 results.sakshi.com/textfile/R_PRES91.TXT
AP SSC PRIVATE Results results.sakshi.com/textfile/P_PRES9.txt
AP OSSC REGULAR results results.sakshi.com/textfile/OS_PRES92.txt
AP OSSC PRIVATE results results.sakshi.com/textfile/OS_PRES92.txt

Sakshi Results
Sakshi Results. Ceep 2009 Results · Inter Second Year 2009 Results · Inter First Year 2009 Results. results.sakshi.com

Results direct links from vidyavision.com

Andhra Pradesh Examination Results-Vidyavision.com

Vidyavision.com provides you Andhra Pradesh examination results like SSC Results , Inter Results, MCA Results, ICET Results, MBA Results, EAMCET Results, ...

www.vidyavision.com

Related

AP SSC results on SMS
AP results links

C Traps & Pitfalls Book PDF Online by Andrew Koenig

noreply@blogger.com (Bhagwat) — Tue, 26 May 2009 12:08:00 +0000

C Traps & Pitfalls Book PDF Online by Andrew Koenig
C Traps and Pitfalls is a slim computer programming book by former AT&T researcher and programmer Andrew Koenig, its first edition still in print in 2005, which outlines the many ways in which beginners and even sometimes quite experienced C programmers can write poor, malfunctioning and dangerous source code.

It evolved from an earlier technical report published internally at Bell Labs, but is now available online in pdf form.

&amp;amp;amp;amp;amp;amp;amp;amp;lt;br&amp;amp;amp;amp;amp;amp;amp;amp;gt;

Happy coding.

Higher Secondary Kerala hse kerala Results Links

noreply@blogger.com (Bhagwat) — Tue, 12 May 2009 08:01:00 +0000

Today vhse kerala HSE Kerala DHSE Kerala hseresults 2009 Plus Two Kerala results are declared, students are finding difficult to get results as official sites are coming down, due to hevay loads, For those students here are some direct links and email registration links.

The result will be made available with the joint efforts of Kerala education board and the National Informatics Centre and to be published on keralaresults.nic.in
Arrangements have also been made at couple of hundred Akshaya Centres to provide the result where internet connectivity is a problem.
here are direct links for email Registration
DHSE (Plus Two) Results 2009
http://results.kerala.nic.in/dhse09/

VHSE Results 2009
http://results.kerala.nic.in/vhse09/

The Kerala Higher secondary examinations Results links

Schools can download the results of all their students. For students and schools who register on www.keralaresults.nic.in, the results would be sent to their e-mail ids soon after the results are declared.

VHSE Results 2009
Likely to be announced on 12 May 2009.
DHSE plus 2 Results 2009
Likely to be announced on 12 May 2009.

Kerala HSE Results 2009, DHSE Plus Two, VHSE Exam Results, Kerala. Government of Kerala Higher Secondary Examination Results 2009. Kerala Higher Secondary Result HSE 2009 - +2 Results hse kerala, higher secondary, vhsc kerala, hseresult, higher secondary education

karresults.nic.in PUC Exam Results 2009

noreply@blogger.com (Bhagwat) — Fri, 08 May 2009 08:13:00 +0000

Government of Karnataka KARNATAKA EXAMINATIONS AUTHORITY will declare PUC Exam Results 2009 by tomorrow
Likely to be declared on 09/05/2009 at 3:30pm

check you Karnataka PUC Exam Results 2009 at karresults.nic.in

source
http://www.karresults.nic.in/

Find Karnataka PUC Results,PUC Exam Results 2008, Karnataka PUC Results 2008, Karnataka Pre University Results,PUC Results only on Sify.com

www.puc.kar.nic.in

PUC Results 2009, Karnataka

PU Education Department, Karnataka will be announcing the PUC Results 2009 on 9th May 2009.

2 puc results, 2nd puc results, 2nd puc results 2009, cet exam results, karnataka puc results, Karnataka Results, Karnataka SSLC Results 2009, puc results 2009, puc results karnataka Karnataka PUC Results | PUC Exam Results 2008 | Karnataka PUC Results 2008 | Karnataka PUC results 2008 | PUC Results

Use of Select() System Call In Linux To make a non-blocking connect()

noreply@blogger.com (Bhagwat) — Wed, 06 May 2009 08:01:00 +0000

About Select system call
The select() function shall examine the file descriptor sets whose addresses are passed in the readfds, writefds,
       and errorfds parameters to see whether some of their descriptors are ready for reading, are ready for writing, or
       have an exceptional condition pending, respectively.
int select(int nfds, fd_set *restrict readfds,
              fd_set *restrict writefds, fd_set *restrict errorfds,
              struct timeval *restrict timeout);
There are many usages of select() system call, Here is one usage in networking applications, The use of select system call is to make non-blocking call in Linux.
how to make a non-blocking connect() in Linux

1. create socket using socket(),

2. set the file descriptor to non-blocking mode using fcntl(2)
fnctl (fd, SETFL, fcntl(fd, GETFL) | O_NONBLOCK)

3. call connect() - since you have set the socket to non-blocking, it will
return right away with a result of EINPROGRESS.

4. Now

a) Go into a loop and keep calling connect() - as long as it
has not completed it will return EALREADY (see man page for
connect()). This is simple but not a good solution. check below solution
       using select to avoid loop wait.
OR
b) Use select(2), selecting the socket for write. When the connect is
finished, the select should return and show the socket as writeable.
Using select() can be tricky, but will be more efficient, since
select() will block until the connect has finished and you are not
wasting CPU in a tight loop.

   /* No loop required */
fd_set write_set;
FD_ZERO(write_set);
FD_SET(write_set, fd);
select (fd+1, 0, write_set, 0, 0);

File descriptor masks of type fd_set can be initialized and tested with FD_CLR(), FD_ISSET(), FD_SET(), and

     FD_SET(fd, fdsetp) shall add the file descriptor fd to the set pointed to by fdsetp. If the file descriptor fd is
       already in this set, there shall be no effect on the set, nor will an error be returned.
     FD_ZERO(fdsetp) shall initialize the descriptor set pointed to by fdsetp to the null set. No error is returned if
       the set is not empty at the time FD_ZERO() is invoked.
The original Standard can be obtained online at http://www.opengroup.org/unix/online.html

Working With Linux Patch 10 Step Guide

noreply@blogger.com (Bhagwat) — Tue, 05 May 2009 08:10:00 +0000

What is Linux patch ?
Here is patch description from Linux Man pages.
       patch - apply a diff file to an original

SYNOPSIS
       patch [options] [originalfile [patchfile]]

       but usually just

       patch -pnum <patchfile

DESCRIPTION
       patch takes a patch file patchfile containing a difference listing produced by the diff program and applies those
       differences to one or more original files, producing patched versions. Normally the patched versions are put in
       place of the originals. Backups can be made; see the -b or --backup option. The names of the files to be patched
       are usually taken from the patch file, but if thereâs just one file to be patched it can specified on the command
       line as originalfile.

How Linux patch works?
Here is short explanation about How to use patches in linux.
Working with Patch 10 step Guide.

mkdir patch_test
cd patch_test/
mkdir old
cd old
create file1.txt and file2.txt
cd .. ; mkdir new
cp file.txt and file2.txt == Now change both or any files to create patch
cd .. ; ls // new and old dir here
diff -Naur old new > learn.patch ==Your patch is ready.
patch -p0 < learn.patch == apply patch to old folder; you should be above old dir

How to Reverse patch applied?
In order to reverse the patch applied run following command.
patch -p 1 -R < learn.patch

Creation of Static Libraries In Linux Simple Steps

noreply@blogger.com (Bhagwat) — Mon, 04 May 2009 07:58:00 +0000

Here is real time example of creation of static library and its usage, explained in simple steps.
Creation of static library with example

Creation of Static Libraries In Linux Simple Steps

1. Create Test Directory
Create working test directory as: /home/test/so

2. Choose Library Files
   library file name: add.c
     int add(int a, int b)
     {
         return (a+b);
     }
3. Compile
Now Compile Static Library with -shared option
   gcc -c add.c
   gcc -shared -o libadd.so add.o

4. Usage of Static Library
Here is example application uses this library.
   filename: main.c
   int main(void)
   {
      printf("result: %d", add(1,2));
      return 0;
   }

5. Compile Example Code
gcc main.c -o main -L <path where the library file is there, in our example it is libadd.so> -l add
       (in last option -l add we have to specify library name. name of the library is, removing the "lib"
         from libadd. i.e. how gcc takes.)
   example: gcc main.c -o main -L /home/test/so -ladd

6. export LD_LIBRARY_PATH=<directory where your .so file is>
    if you copy the .so file to /lib directory no need to set this environment variable

Tags static library, Linux, My Notes, C Programs, Embedded Linux.

The Linux Foundation Free Training Program at linuxfoundation

noreply@blogger.com (Bhagwat) — Thu, 23 Apr 2009 07:31:00 +0000

The Linux Foundation Training Program is:

* For the Community, by the Community. The Linux Foundation is
building the program with its Technical Advisory Board to ensure the
content, instructors and classes are the top quality available.
* Technically the most advanced. Since the Linux Foundation works
directly with community developers, it can cover features and advances
in Linux before commercial companies.
* Connected. The Linux Foundation has unfettered access to the
leading developers and companies in the Linux ecosystem and will use
these connections to best position attendees for success. For example,
attendees can attend the exclusive, invite-only Collaboration Summit
where they can forge connections beneficial to their career.
* Real World. The Linux Foundation training courses all have hands
on components and a highly rigorous curriculum of programming or
administration exercises. Graduates will be well equipped to master
Linux programming and system administration tasks

The Linux Foundation Training Program will span the enterprise server
and mobile and embedded markets, with courses being offered on the
following subjects:

* The latest filesystems
* Device driver development
* Kernel internals
* Advanced systems administration
* Kernel debugging
* Application development
* Power Management & Optimization

These courses will be provided in three core offerings:

* Training offered at the Linux Foundation Collaboration Summit
and LinuxCon allowing developers to attend advanced training as a part
of their conference experience.
* Courses held in cities throughout the U.S. and around the world
* Custom courses for corporations who need training to help
advance their developer core
For more information, please contact training (at) linuxfoundation dot org.
source http://events.linuxfoundation.org/training