If you want to build your own disk array, let’s say RAID, on your computer to increase disk space and efficiency, you should know about few important things in general:

• You can consider MBR and x86 obsolete. New way is GPT, UEFI, AMD64.
• Large RAID arrays (over 2TB) will not work with older hardware and OS (except FreeBSD) due to architecture limitations.
• To use large RAID volumes you must use GPT partition scheme. MBR will not do the job.
• Some systems can use GPT only with UEFI BIOS (i.e. Windows works with GPT only via UEFI). You may be forced to buy new motherboard.
• UEFI and GPT is totally different way of bootstrap so you can forget what you know about BIOS and MBR here.
• Hard Drives have hidden corruption-fix mechanisms in firmware that will make your RAID array fail to operate. For RAID choose dedicated drives such as WD RED (not Green, not Black, not Blue).

In order to use GPT and UEFI I have replaced my nice ASUS M4A88TD-V EVO/USB3 motherboard with M5A97 R2.0 only because M4 series did not support UEFI. New BIOS is totally different, but I am not really sure if replacing the hardware was mandatory..

Summing up, if you want to use large RAID volumes make sure first that you can use GPT and UEFI BIOS is present on your AMD64 hardware. If not, still you can use the FreeBSD as it knows how to bypass some limitations. Also remember to use dedicated HDD for RAID operations.

If you find keyboard/mouse to be missing when installing Windows7 on a new hardware, make sure you are connected to USB2.0 ports not USB3.0. New hardware host of USB3.0 may not yet be supported by older installer software.

In order to create OSX installer on USB memory drive you need to:

• Download the Mac OSX Yosemite installer from AppStore on you Mac.
• Create installation media from Terminal by executing following command (remember to adjust YOURUSBVOLUME value):
  
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/YOURUSBVOLUME --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction

• Boot target Mac from USB by pressing ALT/OPTION key while powering-on the computer.
• Remember to format target drive first with Disk Utility if you want to perform clean installation.

If you want to perform a fresh installation of OSX 10.10 Yosemite on an older MacBook(Pro) you can obtain the installer with AppStore and then create the USB installation media.

In case you encounter an Installer Verification Error that prevents you from installing the new system try the following. Its not the system date not bad download as internets says.

This may also help you when encountering problems (i.e. USB Mass Storage) after system upgrade to Yosemite.

Try these boot keyboard shortcuts until you hear boot sound two times:

• Cmd+Alt+R+P when powering on the Mac (NVRAM Reset)
• Alt+Ctrl+Shift+PowerON alltogether (SMC Reset)

No problem, you are wolcome :-)