oracle to_date

Many times working with Oracle SQL, I need to check how is the syntax of this function here a good reference with examples oracle to_date

Oracle Enterprise Linux 6.3 Installation

An step by step Oracle Enterprise Linux 6.3 Installation on VirtualBox

http://zoomerhammerball.sytes.net/wiki/index.php/Oracle_Enterprise_Linux_6.3_Installation

Extend vdi disk on VirtualBox with Windows 7 guest

When we install an OS for a VM it is possible that we estimate a size that now is not enouth and the disk is little for our working needs. With Windows 7 guest it is possible to extend the partition:

1. Create a new vdi disk with desired size
2. Clone: VBoxManage Initial.vdi New.vdi --existing
3. Change SATA-0 port disk with new vdi file
4. Start VM
6. Control Pannel > Admin Tools > Host management > Storage > Disk Management
7. We can see our disk with not assigned space
8. Click right button in primary partition and extend

New disk is new available free space to work.

Shared clipboard stops working on VirtualBox

Shared clipboard stops working between guest to host. It begins working fine but at a given time stops. My solution was restart VM, but looking into the problem it is related with VBoxTray program. My environment is:

• VirtualBox 4.1.8
• Host Ubuntu
• Guest Windows XP

The problem is inside the guest, to fix it is enough to stop VBoxTray program and start again. Bellow a little script to restart the service when clipboard is not working:

@echo off

taskkill /F /T /IM VBoxTray.exe

start VBoxTray.exe

exit

Put this code in a cmd and throw it when the problem occurs.

VirtualBox compact vdi files

Many time running an operating system on a VM, installing/deinstalling software, copying and removing data... the size of the vdi disks increase too much. But if we check the storage on guest system, the difference between vdi file and used space is huge. It is the moment to compact the vdi file.

In my case I have a Windows XP guest running on Ubuntu 10.04 x86_64 host. The size of the vdi fileis 84GB. Bellow the process to compact:

1. GUEST: Defragment guest disk on VM OS.

2. GUEST: Execute SDELETE, to release unallocated space of deleted files, then VBoxManage compactor detect this sectors are unallocated and can free them. Wait... depends on size of vdi file.

C:\> sdelete -z -c C:\

3. Stop VM

2. HOST: Execute:
VBoxManage modifyhd WindowsXP.vdi --compact

Performing these actions my vdi file goes from 84GB to 40GB.