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Articles from Eko Wahyudiharto Blog

Simple MySQL Replication Using FTP 2007-06-19 20:07:00 This problem happened to me while finishing my other web based project not so long ago. The scenario was too complex to imagine, but both server must synchronized & had the same record as another in a second. Let see the picture below:From the picture above, the website visitor accepted to submit their data. While the local server also serve the local data transaction in LAN. So what the point is?Yes! The thing is … the servers are separate each others. The first server (dedicated as the data center) are served for public internet access which take a place on commercial hosting machine. This web server – as any commercial web hosting – are restricted from any way, except from the user or web administrator who connect from the browser (known as cPanel). There might be no free SMTP port to use, no direct MySQL connection from third party software, limitation to connect to the FTP service automatically. In manner logic, there is no possible way to synchronized both the servers autom ...

(Another) MySQL Incompatible Built-In Function 2007-06-18 20:49:00 The password built-in function in MySQL has different hashing engine since version 5 released. While this issues has been found by my own self after having a tiny research on how to synchronize the both different version in my latest web based project at State Education Department (Departemen Pendidikan Nasional) just couple days ago.Incompatibility effect had been detected after using the function on the login form. The validation process somehow has failed, even the variable seemed OK. It was proved when I tried execute the SQL query manually. Get a common command below in both MySQL version ...

Hard Drive Benchmarking from Linux 2007-06-05 20:37:00 If you trying to find out a similar application likes HDBench in Linux, perhaps you would like consider to use hdparm. This small application basically figuring out the harddisk parameters. Combined with several options, it could be a powerful toy to stressing your hard drive. For instant, see below default structure command:# hdparm [ flags ] [device]As written on it’s manual, to start benchmarking process you can simply set the flags parameter with –Tt. While the device parameter replaced with your hard drive assigned to device files (/dev/hdx). Watch for the example below:# hdparm –Tt /dev/hdaThe command above will resulted timing cache reads & timing buffered disk reads. Both on MB/sec unit. So, what is –Tt actually means? The first “T” parameter perform timings of cache reads for benchmark and comparison purposes. For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system (no other active processes) with at least a c ...

Birthday 2007-06-04 22:09:00 Nothing special happened but yesterday is my anniversary. The notice above came when I opened my mailbox on Sunday morning in office & it tried to prove that the message is the first “mouth” which saying happy birthday words to me. Yup, I was designated that way to created the small happiness to the members who joining the corporate website. Also, as well as supporting the Customer Relationship Management on it.The concept was clearly simple. Every 01.00 AM, there is a script executed by a crond daemon (crontab) on the web server which running a search & querying thousands of members which having birthday on the current date. If they are exist, one by one member are sent the email script generated by the add in custom made module integrated to the website.0 1 * * * /usr/bin/php –f /var/www/html/your_script.phpOn a web server running an SMTP server integrated to the same machine, there will be no problem at all. But, what about if they had separated on each different machine & loc ...

A Week of Weak 2007-06-03 21:38:00 On last Friday, i was in Pekanbaru to complete my current project. I was there for couple days to practice the operators about how to use the application. Well, the task was done successfully. On Saturday evening, i had to catch my flight to Jakarta since there was another official journey to do for the next evening.(Day 1) Jakarta - YogyakartaMy superior official & me had been assigned the task to implementing the latest application in several branches & regional offices to over come a special product released before. The first point to visit was Yogyakarta regional office & a local branch.(Day 2) Yogyakarta - PurbalinggaNext city to visit was Purbalingga branches. It took 5 hours from Yogyakarta traveled within a car to get to it. The route takes from Kutoarjo, Kebumen & Banjarnegara.(Day 3) Purbalingga - WonosoboFrom Purbalingga, the journey continued to Wonosobo branches. The trip to get there took about less then 3 hours. An interesting typical local food between the city shou ...

CDMA Internet Connection from Linux 2007-05-23 00:52:00 How to create an internet connection using CDMA network from a phone cellular in Linux? This is a new topic for me after there was a Nokia DKU-5 connection cable passed me by just for few days ago (Many thanks to Wisnu for borrowing me the cables). Obviously, there was no problem at all to make the connection within it since the configuration just takes the same from the Windows setting. Of course that you will see a different interface over Linux with kppp dialer application. One advantage is that you don’t have bother with the driver software installation, because it should automatically assigned to the native driver provided by the kernel.The phone cellular I used was a cheap Nokia 6015 CDMA. I bought it over a year & got paired it with Fren CDMA SIM card. The DKU-5 data cable came with the USB port connection (I’m not sure whether it is genuine or not). Currently, I tested it from Linux Fedora Core 4 with standard kernel 2.6.11 from my laptop.When it plugged to the USB port, th ... Internet

How to Grabbing Data from Other Website? 2007-05-21 20:41:00 Lot of PHP reguler expression samples are spread over the internet. This PHP standard function having great advantages e.g.: to grab data from other websites. On this current article, I’d like to share you about how to grabbing currency rates data from Departemen Keuangan website. The script was taken from my Web Design Competition result held by Dirjen Pajak Indonesia in the end of 2006.The PHP reguler expression preg_match function usually used to perform a reguler expression match. It searches subject for a match to the regular expression given in pattern. See the formula syntax below:int preg_match ( string pattern, string subject [, array matches [, int flags]])If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized sub pattern, and so on. preg_match() returns the number of times pattern matches. That will be either 0 times ( ...

450 Fresh PCs Inspecting 2007-05-20 20:25:00 The task to inspecting total of 450 new Z*rex computers on it’s factory has been done. Me & the team consists of 10 man just already did it in 3 days. This all brand new PCs was ordered from the company I’ve been worked after having a selection criteria to choose much lower price with better performance & hardware specification (what an usual criteria!). Lot of certified PC vendors was submitted to join the beauty contest before. Some of them came with world trade name, such as HP, Acer, Dell & much more. At the end, the local PC Z*rex won the competition (again, with an annoyed thing!).The OS agreement as listed on the official appointment was so simple. They only have to plugged in the Linux Fedora Core 4 appropriated to our condition in order to support our plan to moving from Windows. The thing is we have to check, test & finalized the agreed hardware specification & also the system configuration one by one PC… manually. Fiuh… better no to do that by your own finger ...

On Mobile Web Coding 2007-05-14 20:14:00 Sometimes, you will face a condition when you have run out of coding times. For example, you are on mobile and there is no chance to turn on the laptop to finishing your web based project. In this situation, I only depend upon my PDA. Make sure that you have installed your favorite file manager, text editor & high capability of internet browser also full of battery on it. My favorite file manager is Total Commander. It is a PDA version of Norton Commander which has high integrity with the text editor. For me, it is more powerful than a standard file manager. Editing the sources is as much easiest as you developing over the computer. Just select the file you want to edit & press the Notepad likes icon at the bottom of the display.Now, you are working on the editor. Imagine that you have working on a notepad. So, there will be no code completion or something to automatically fix the source. All is depend on your self. Just make a save, undo, trial & error with the browser.Internet browse ...

News from Surabaya 2007-05-06 20:28:00 I'd been become an agent to represent the meeting scheduled in Surabaya held by Yayasan Dana Sosial Mandiri (YDSM) on May 5th yesterday at the Novotel. By now, the foundation is having a co-operation with the company where I’d been worked specifically in a funds channeling. The session was talked about the latest release of consolidation application which must be used on the branches to monitoring how much the funds are being channeled to the clients by each branches. At least, there are about tens of regional bank member from the foundation. Each of it are stayed on each of provinces spread from all over Indonesia.Personally, the application is just fine for me. The interoperability of the program can accommodate each member as well. But they seem loosing for something critical points:1. The system was developed as stand alone application with distributed data stored on each client. This situation make each members of the foundation are being secluded. They are just not only facing ...

Windows XP in a Stick 2007-05-02 20:36:00 Recent days, there are so many Linux comes with live CDs. This is an alternative way for those who doesn’t want to install Linux on their hard drive. The live CD also become a problem solver when the system wont boot up or something happened with the system & you may rescue the files with CD. Beside the CDs, one of merely known Linux named DSL (Damn Small Linux) are comes with damn live USB! Note that this method required a computer which have ability to boot from USB devices.By the chance, I heard something about Windows XP live in a USB flash disk. This is much interesting for me & would like to tried it. In a seconds, there was a secure link referred to the download page from Google. It size’s about 54MB & the link are here.After it had completely downloaded, the packages are being extracted with WinRAR ~ since it is compressed with RAR format somehow. Finally, there are 7 files extracted from it. The first 2 files are the manual in Germany & Russian language. You might ...

VirtualBox: Another Open Source Virtual Machine (Part III) 2007-04-30 22:11:00 From the previous serious problem, I have to make a solution about how to bridging on Linux hosts over the VirtualBox, but I great successfully working on it. From the documentation available, the VirtualBox implemented Host Interface Networking with the Linux kernel's own TAP interfaces. Therefore, make sure that Linux kernel has support for TUN/TAP enabled. While the additional drivers are then not required, the TUN/TAP packages are not available on Fedora Core 4 setup CD’s. There are at least 3 packages are needed to enabled it.tunctl utilityWith TAP, the Linux kernel can simulate Ethernet interfaces that, instead of being attached to networking hardware, communicate with VirtualBox. The TAP interfaces therefore appear like physical network interfaces (e.g. eth0) on the system. To create a TAP devices, use the tunctl utility. For Fedora Core 4 release, have a download session on this link.brctl utilityBridging, then, is a feature provided by the Linux kernel and can be controlled ...

VirtualBox: Another Open Source Virtual Machine (Part II) 2007-04-27 22:03:00 For more furthers, I had tried to run the VirtualBox with the same version of Linux Fedora Core 4 in a multiprocessor machine to test how far the compatibility on it. They just did it well. The VDI image file from the previous machine was copied into this multiprocessor machine & it run normally without any problems. So it is as simply as plug & play since I don’t have to create the Windows 98 from scratch to do the test.Anyway, there are some serious problems I face within it. If you have the features of SELinux enabled, just turn it off since it will produce an error messages said something like "/opt/VirtualBox-1.3.8/VirtualBox: error while loading shared libraries: /opt/VirtualBox-1.3.8/VBoxVMM.so: cannot restore segment prot after reloc: Permission denied". Another solution to solve the problem is trying to change the information security context file with the command below:$>chcon -R -t texrel_shlib_t /opt/VirtualBox-1.3.8/*.soOther errors you might face, if the VirtualBox ...

VirtualBox: Another Open Source Virtual Machine (Part I) 2007-04-25 20:35:00 Somehow, an application that highly needed in the company I’ve been worked was failed to run with Linux upon the emulator. This application specifically ~ recognized from the meta file information ~ build from Visual Basic 6, using the Microsoft Access as the database storage & also requiring Crystal Report library to previewing the reports. Actually ~ as anyone can see ~ this is the very basic application & might run on emulator such as wine or crossover. From the global process explained by the programmer in US, I also found that it depends on some RPC (Remote Procedure Call) or similar process which didn’t exist in the emulator (it is a kind of thin client application models which try to connecting the server with VPN technology). Just a times before, I had tried several bottles methods from the latest version of wine or crossover but it seems can’t worked in any way.After being get some failed & frustrated on how to emulating it, finally now I’m working on a different w ...

(Is It) A Bug in MySQL 5? No Way! 2007-04-19 20:14:00 In the last days, I’ve been around with MySQL 5 to tested my current desktop application project which actually developed from Borland Delphi 6 & MySQL 4 as the back-end storage. Anyway, this is my first time experiment to tried to run it not with the same version. This MySQL 5 are comes with standard package from Linux Fedora Core 5 & I had successfully already installing it to one idle computer as the dummy server.At a glance, there is nothing seems to be wrong after the application has run. The login query are succeeded to execute, also others form which querying common text field data types are resulted fine. Not so long ago after that, I’d countered a weird exceptional error. It said that field ‘xxx’ is not found. Get hurry checked it out from MySQL-Front but this decimal (x,y) data type named ‘xxx’ is exists. Time by time, I resumed that others same decimal data type also reported being lost. Very odd indeed I thought.At first, I thought that the problem are cause ...