Ubuntu 9.04 Vmware Arrow Keys Problem

I finally found how to get all those keys working on my newly installed Ubuntu 9.04 with my XP VM. The issue is that all the arrow keys and delete key don’t work. There are others too but not listed. So a bit of googling, I found that you have to map the keys in a vmware config file to solve the problem. So this is what needs to be done.

1. Edit /usr/lib/vmware/config
2. Add the following to the end.

xkeymap.keycode.108 = 0x138 # Alt_R
xkeymap.keycode.106 = 0x135 # KP_Divide
xkeymap.keycode.104 = 0x11c # KP_Enter
xkeymap.keycode.111 = 0x148 # Up
xkeymap.keycode.116 = 0x150 # Down
xkeymap.keycode.113 = 0x14b # Left
xkeymap.keycode.114 = 0x14d # Right
xkeymap.keycode.105 = 0x11d # Control_R
xkeymap.keycode.118 = 0x152 # Insert
xkeymap.keycode.119 = 0x153 # Delete
xkeymap.keycode.110 = 0x147 # Home
xkeymap.keycode.115 = 0x14f # End
xkeymap.keycode.112 = 0x149 # Prior
xkeymap.keycode.117 = 0x151 # Next
xkeymap.keycode.78 = 0x46 # Scroll_Lock
xkeymap.keycode.127 = 0x100 # Pause
xkeymap.keycode.133 = 0x15b # Meta_L
xkeymap.keycode.134 = 0x15c # Meta_R
xkeymap.keycode.135 = 0x15d # Menu

3. Save it
4. Restart vmware

Thank goodness. What a pain this was to use with a whole bunch of keys not working.

GRUB Error 21 Dual Boot Raid

I was installing Ubuntu to dual boot onto a newly added drive on my workstation that already has Windows XP. After the installation, GRUB gives me error 21. I looked through all the forums and help and tried everything from reinstalling GRUB to modifying menu.lst. Nothing worked. Then I figured out what the problem was. My system before adding the new drive had three drives; one with XP OS and two in a Raid 1 array for data. The issue was the Raid 1 array. With the new drive I added for Ubuntu, the computer had four drives. During installation, Ubuntu saw four drives and when installing GRUB, it pointed Ubuntu to boot on hd3,0. However, when GRUB tried to load, the BIOS was showing only three drives and hd3 was non-existent resulting in error 21.

Then I decided to move my SATA cables around so the location of the Ubuntu install does not change no matter if we saw the Raid 1 as one drive or two. So I kept XP on hd0, moved Ubuntu to hd1, and then having the Raid 1 drives to follow with hd2 and hd3. At this point, I reinstalled GRUB and tried to boot up again with the Raid 1 configured in the BIOS. Now I get GRUB error 17! What the heck is that? I found that if I got rid of Raid on the BIOS, error 17 goes away and GRUB comes up without a problem.

I got tired of trying to debug this and decided to just go all Ubuntu and just VM XP for the few things I still need to do on Windows.

Setup Ruby On Rails on Windows

http://wiki.rubyonrails.org/rails/pages/HowtoInstallOnWindows

This is where to get the fastcgi dll.
http://www.fastcgi.com/dist/

Sample Apache virtual host configuration

<VirtualHost *:80>
<Directory “C:/data/projects/testapp/public/”>
Options Indexes FollowSymLinks
AllowOverride All
Order allow,deny
Allow from all

</Directory>

Options ExecCGI FollowSymLinks
AddHandler cgi-script .cgi
AddHandler fastcgi-script .fcgi
ServerAdmin webmaster@testapp.dev
DocumentRoot “C:/data/projects/testapp/public/”
ServerName testapp.dev
ServerAlias www.testapp.dev
ErrorLog “logs/testapp.dev-error.log”
CustomLog “logs/testapp.dev-access.log” common

</VirtualHost>

Mysql on 32bit processor vs 64bit processor

Here is the continuation of the experiment done previously on Mysql on Windows vs Linux. After doing more analysis and observation, it appeared that the difference in speed for the benchmark tests were not related to Windows and Linux but were related to the processor. The previous test just happened to have AMD 64s on the Linux machines and Intel Xeon 32bits on Windows. We hypothesized that the increased throughput of the 64bit processors resulted in about half the time required to return the same query run on a 32bit machine.

View the previous results

So we decided to test the same query again on a Windows machine with an AMD 64 X2. This time the result for the query took 7.35 second, almost the same as the other AMD 64s running Linux.

One more test to run the query on a Windows Intel 64bit chip machine would better solidify our hypothesis.

Mysql server has gone away

I have a spider crawling the web written in PHP running constantly to insert and update data in a Mysql database.  Today, it kept stopping on a records with the error message, “Mysql server has gone away”.  It certainly did not time out as just starting the process again would result in this message immediately.  The script did not close out the connection to the DB as it had worked just fine for over a year.

Finally, I found that the problem was max_allowed_packet setting in my.cnf was too small.  It was set to 2MB and when Mysql receives a query larger than that, it assumes that something must have gone wrong and closes the connection.  I increased that parameter to 4MB and everything is working fine now.

Mysql SQL_NO_CACHE Benchmark Problem

I have been trying to benchmark the sql calls to mysql from an application without success. Even when I set the SELECT statement to SQL_NO_CACHE, the results seemed to be still cached. Apparently, Linux does its own caching of disk reads also. That was giving me incorrect benchmark results if I hit the same data twice.

For those using Linux kernel 2.6.16 or higher, you can clear Linux cache with the following command.
echo 3 > /proc/sys/vm/drop_caches

Unfortunately for me, I am stuck on 2.5.xx and will have to figure out another method.

zen cart Warning: session_start() No such file or directory (2) in /dir/public_html/includes/functions/sessions.php on line 102

The error comes up when trying to use file based session storage instead of database. Apparently, the configuration for what directory to store the session is not in the configuration files but in the database table “configuration”.

If you upgrade your php to version 5.2.1, the database session storage breaks. Therefore, I had to switch to file system based storage. But the catch was that I no longer could log into admin as the session could not start. The configuration.php files did not have this constant.

The way to fix this is to log into your database and update the session directory record.

“UPDATE configuration SET configuration_value=’/your/new/direcotory/’ WHERE configuration_title=’session directory’;”

System Specs:
php.5.2.1
zencart 1.3.5
apache 1.3.37
MySQL 5.0.45

Apache SSL IfDefine – Error

Just encountered a problem that was painful to deal with while configuring SSL on apache for linux.  The httpd.conf had a tag, , before all the SSL configuration lines.  In order for any commands within and to be loaded on service start, you must use the -D attribute like this.

$ service httpd -D SSL -k start

Also, I found that restart does not always take new changes to my conf files.

$ service httpd -D SSL -k restart

Instead, use the stop then the start command to be sure.

$service httpd -D SSL -k stop
$service httpd -D SSL -k start

That was a source of much pain while working on this particular server.