Walker News » KnowHow

Broadband Internet Reliability and Latency Are Important Than Speed

Walker — Sun, 31 May 2009 13:22:14 +0000

I am sick looking at ads and promoter over emphasizing the broadband Internet speed but nothing is related to broadband reliability and network latency. Anyway, in reality which ISP dares to highlight its own weakness?

I do not know what slowest broadband speed in today market is, but I do know that 512Kbps is enough for me to watch YouTube video at HQ quality and most of media-rich websites without much “pain”, except the fact of not able to stream multiple videos or load too many web pages concurrently.

I am not a big fan of online game, but I think 512Kbps is not good choice anyway for playing the modern games online.

Broadband speed

Apparently, the higher the broadband speed is better, meaning that greater bandwidth is available to channel more data between the computer and Internet in a second.

Therefore, using high-speed broadband Internet allows end user to complete download big files like Windows Vista SP2 or the latest Ubuntu CD/DVD-ROM image in the shortest time relatively.

These are the facts that ISP ads or broadband promoters would tell.

Broadband reliability and latency

But, there is no statement touch on broadband reliability and network latency.

For example, if on and off the ping test to some of the reputable websites shows more than 5% of packet loss and/or latency higher than 500ms, you might not able to login to these websites over HTTPS or secure connection.

Although, the effect is not magnified if you simply looking at the download speed or browsing media-less web pages of these sites.

In other words, bad broadband reliability and network latency can minus the benefit of high broadband speed offered to you by the ISP.

In my experience, some of the ISPs are actually segregate subscribers’ broadband connection to the Internet by different default gateway, i.e. some users (especially new subscribers who are under cooling period or light-weight users who are below monthly bandwidth quota) are routed to a better Internet backbone while the less valuable users (like those who subscribe the slowest speed package or users in heavy-usage category) are allocated with a congested trunk that lead to the Internet.

In this case, you will likely have a good connection to some sites hosted in home country but face problem of high packet loss and/or latency with some websites hosted at other countries.

Verdict – Do not just look at the speed; be mindful on the broadband Internet reliability and latency, when choosing a broadband contract in your area or when filing complaint to the call center regarding similar kind of connection problem.

How To Fix Windows Live Messenger Login Error Code 80048820?

Walker — Tue, 07 Apr 2009 16:43:39 +0000

I am not sure that this trick works for all of you who are Google-ing help related to Windows Live Messenger key ports failure or error code 80048820.

However, see it and believe it, as I have just made another “silent” screencast for reference.

Problem: I was able to sign in Windows Live Messenger at Starbuck before crawling to office this morning.

However, the login failed after connecting the same laptop I used at Starbuck to corporate network and started to online via proxy server.

No matter how many times I tried to login with different “tweaks” applied here and there, the darn error code 80048820 (extended error code 80048416) keep pops up to upset me :-(

The Connection TroubleShooter showed “key ports” failure and suggested that could be caused by improper proxy server or firewall settings:

However, proxy server was not the culprit, as Connection Tester indicated a successful remark. It’s not firewall of any kind too that cause this problem.

So, what will be the likely cause? How to fix the “meaningless” error code 80048820 or extended error code 80048416?

After filtering hundreds of Google search result, I got this useful link from MSN@China.

Out of few solutions stated in the page, I found that by disabling Check for server certificate revocation option in IE8 works out well for my case (login via office network with proxy server and firewall):

How To Reset DB2 Database Configuration To System Default?

Walker — Sat, 07 Feb 2009 16:51:08 +0000

With IBM DB2, each database has its own database configuration file which contains values for various configuration parameters that affect the use of the database.

Prior to DB2 8.2, this file is called SQLDBCON, and it’s changed to SQLDBCONF for DB2 8.2 and above.
You can find the database configuration file at database_directory/db2_instance/NODE0000/database_entry/, where both database_directory and database_entry can be found from db2 list database directory.

Alternatively, execute the Linux command find . -follow -name "SQLDBCON*" at DB2 instance directory.

Although the database configuration parameter values are stored in a physical file, you should never edit or open the file for inspection with any non DB2-provided utilities. If this file is edited accidentally during open for read session, you might have to restore the database from backup for recovery.

While there is not only one DB2 program to deal with SQLDBCONF file, I prefer the DB2 CLP (a.k.a. command line processor). For example (assume the database connection is established):

To view or print DB2 database configuration file

db2 get db2

To display both current and deferred DB2 database configuration parameters value (some parameter value changes are not effective for the current active connection until the client initiate a new database connection):

db2 get db cfg show detail

To update DB2 database configuration for a parameter called LOGFILSIZ (Log file size)

db2 update db cfg using LOGFILSIZ 2000

If for some reason you need to reset the DB2 database parameter changes to system default, disconnect the active database connection and execute reset db cfg (either one of this CLP command):

db2 reset db cfg for database_alias

db2 reset database configuration for database_alias

where database_alias refers to the target database (usually database name and database alias is the same).

How To Check Windows Uptime?

Walker — Thu, 05 Feb 2009 16:16:43 +0000

For those who are using or familiar with Linux know there is a simple uptime command to check how long the system has been running since the last boot-up to the time of executing the uptime command.

How about Windows OS? Does Microsoft provides a simple command to check Windows OS uptime at a glance? Well, there is exactly a Windows uptime program, but it is not with the default Windows installation.

So, you have to download the Windows uptime.exe and save it to Windows system folder or one of the folder defined in the PATH environment variable (at Windows command prompt, type echo %PATH% to check).

According to KB232243, uptime.exe requires at least Windows NT 4 SP4 and up to Windows 2000 Professional.

Nevertheless, it’s working on Windows Vista SP1 as well. The only problem with my Vista SP1 is when the server service is stop or not running, it fails with message that says, “UPTIME was unable to connect to host”:

^{Windows uptime command fail if the server service is not started or not running.}

For people who believe fewer programs are better (like me), you could refer the alternative, built-in functions to check Windows uptime:

net statistics – At Windows Vista Command Prompt window, execute any one of these commands:

net statistics workstation | find "since"

net statistics server | find "since"

net stats work | find "since"

net stats svr | find "since"

systeminfo – Again, at Windows Vista Command Prompt window, execute this command (the Time keyword is case-sensitive):

systeminfo | find "Time"

Windows Task Manager – For Windows Vista SP1, the Windows Task Manager inbuilt the most straightforward Windows uptime statistics that everyone can tell at a glance:

^{Using Windows Vista Task Manager to check Windows uptime statistic.}

Using Linux Awk Regular Expression To Read Big Log File

Walker — Mon, 02 Feb 2009 09:47:08 +0000

Before I know there is a DB2 utility called db2diag to analysis db2 diagnostic log file content, I use a Linux command called awk with its regular expression function to extract diagnostic entries of the particular day on a specific hour.

Although I’m not a certified awk programmer, I consider myself familiar with this scripting language that’s efficient for processing files of text.

So, when a DB2 server crashes, it’s quite easy for me to analysis an unmanaged db2diag.log file that has grown too big to open in a general-purpose text editor (e.g. Vi or Vim editor in Linux).

Anyway, db2diag is only good for db2diag.log file. If you would like to open and read a huge log file of other application, the Linux awk and tail commands might work (or save your back)!

How to use Linux awk programming and regular expression to read a big log file?

Use the Linux tail command to analysis the log file content, in order to understand log entries pattern.

Using the db2diag.log as an example, each event / incident is initiated with a line that contains date and time:

2008-01-02-10.52.47.720435+480 I1840G300          LEVEL: Event

Then, I use the awk and its regular expression to filter out all log entries that match the particular day and hour of interest:

First, find out the record number of first log entry that match the date and time pattern using its regular expression (RegEx) function:

awk '{if ($1 ~ /2008-01-16-17/){print NR}}' < db2diag.log | head -1

Next, find out the record number of last log entry that match the date and time pattern:

awk '{if ($1 ~ /2008-01-16-17/){print NR}}' < db2diag.log | tail -1

Finally, use awk again to extract or filter all log entries within the range of first and last record numbers that we’ve known from last two steps:

awk '{if (NR >= 7529 && NR <= 8382){print $0}}' < db2diag.log

Because the nature of db2diag.log, the last record number I get from awk doesn’t include the detail of DB2 event / incident happened on that particular time. Thus, I purposely top up the “last record number” (suppose the last record number reported by awk command is 8382, I rest it to be 8390):

awk '{if (NR >= 7529 && NR <= 8390){print $0}}' < db2diag.log >tempfile

If you would like to output the extracted log entries to another temporarily file, just redirect the standard output of awk command to a temp file as you wish (e.g. append >tempfile to the end of last awk command sample).

Brief note about the awk programming syntax used in the sample codes at above:

$1 ~ /2008-01-16-17/ means to check if 1st field/column text pattern matches with the regular expression (i.e. 2008-01-16-17).

Unless the field separator (FS) is specified, awk regards space as field separator by default.

The first field (a.k.a column) of a line (awk treats each line as a record) is denoted as $1, 2nd field as $2, and so forth. The $0 is simply means all the fields/columns of the line/record.

Thus, the combination of awk programming and organized text files can form a simple database system!

The awk regular expression pattern is enclosed by a pair of slash character (/).

The awk RegEx operator for match comparison is a tilde/swung dash character (~). (refer to GNU awk notes on Regular Expression).

print NR is meant to print the record number (NR), i.e. the line number in the log file. To print the number of field/column in a line/record, use NF.

How To Install Cambridge Talking Dictionary For Nokia 5800?

Walker — Sat, 31 Jan 2009 11:49:48 +0000

Besides the free Nokia Maps, Cambridge Talking Dictionary is another most wanted Symbian freeware for my Nokia 5800 XpressMusic.

Indeed, I use this talking dictionary almost every day to learn new words and pronunciation, more than the “silent” bi-directional English-Chinese dictionary bundled with the phone (shame to tell you that how poor I’m in English :(

This mobile dictionary is big in term of size, about 79 MB even after compressed into zip file format (the biggest Symbian freeware I’ve found so far).

The file size is a result of its rich feature, such as explanation and sample sentences of the word in both English and Chinese, voice synthesis (word pronunciation), US and UK English phonetic symbol.

How to install the zipped Symbian Talking Dictionary freeware to Nokia 5800?

Download and uncompress the zip file (TalkingDict.zip).

At this time of writing, there are four directories (respectively named as Data, private, resource, sys), ReadMe.doc, and TalkingDictionary_S60_SA_signed.sis.

According to the ReadMe.doc, you should copy all the contents (the four directories and one SIS installation file) to the root directory of memory card (i.e. Nokia 5800 E: drive).

However, your memory card bundled with the original Nokia 5800 is very likely contains some of these folders. If you simply copy all the unzip contents to memory card, you’re replacing existing folders.

Is it safe to replace the existing folders with those extracted from Talking Dictionary zip file? I think so, but I didn’t follow that way suggested by ReadMe.doc.

When the existing folder is replaced, the existing folder content are preserved if the new folder contents are not having the same file name as those in existing folder. The properties (date/time, permission, ownership, etc) of replaced folders/files are definitely modified.

I’m lazy to check and confirm the effects of replacing existing folders. The best and safe bet is not to replace them at all.

So, I copy the extracted folder to memory card if that particular folder is not in memory card. Otherwise, the contents of the extracted folders are copied to existing folders in Nokia 5800 E: drive (memory card).

The SIS program installation file is transferred to the root of E: drive.

Lastly, press the Nokia 5800 menu key, go to Application, File Manager, E: Memory Card and “double click” the TalkingDictionary_S60_SA_siged.sis to begin Symbian program installation.

If you encounter expired certificate error, please refer to “How To Fix Nokia 5800 Expired Certificate Error During SIS Installation?“.

Once installation completes, the Talking Dictionary shortcut should appears in Nokia 5800 Application folder.

How To Relocate Or Change Google Chrome Cache Folder Location?

Walker — Fri, 26 Dec 2008 06:02:58 +0000

If you have a reason to change or relocate Google Chrome default cache folder to other directory or even different disk partition, the chrome.exe comes with a command line option switch to do the job.

It’s pretty easy that everyone can make it – no complicated step, not an advanced skill, no registry change, doesn’t required third party program – the magic of command line option switch, a good old concept that are mostly found in Linux / Unix or Windows command line utilities.

Anyway, if you have doubt, just spend 2 minutes watching the screencast below (another silent-video but should serve purpose well than my poor writing skill :-(

If you have good broadband connection, this screencast is available in High Quality video mode (HQ) for better visual experience. Check it out at WalkerNewsdotnet Channel.

How to change Google Chrome default cache directory

This work is tested and proved with Google Chrome v1.0.154.36 (and should be working in future release, hopefully):

Right-click the Google Chrome program shortcut and select Properties from the menu
Append the chrome.exe command line option switch at the end of program path in Target text-box:
```
--user-data-dir="type the full path of your own cache folder here"
```

Takes note that you must specify the full, absolute path of the user-defined cache folder for --user-data-dir option to work as you wish.

Unlike the --user-agent that change the Chrome user agent string, the --user-data-dir command line option switch is effective as soon as you double-click the “tweaked” chrome.exe shortcut without having to close all chrome.exe process and restart the Chrome browser.