Strange & Unexpected MyBook Behavior

[BarkingGhostar]

I bought a couple of MyBook Essentials not too long ago and connected them USB3 to a Windows 7 computer with USB3 on the motherboard. On each one I left as factory configured and simply dropped some VOB files along with a bunch of RAW images to a mix in file sizes as part of the test.

Both performed as expected and as identical as one might expect after dropping 2.5TB onto the 3TB drives. I then disconnected them from the Windows 7 computer and connected them to a Windows XP Pro computer. During initialization drivers installed and only one of them was seen.

But the problem was well before the the operating system. During POST the system hanged and would not proceed until I disconnected one of the drives. It made a difference in which one I disconnected as disconnecting the other didn't help. For someone reason one particular drive would hang POST.

I took them back to the Windows 7 computer and again they worked perfectly. Also, the one drive that didn't hang POST on the XP computer was also fine. I made sure this wasn't a case of overlapping drive letter assignments, but even if that were the case this shouldn't express itself at POST.

Both drives have their own external power supply and swapping the PSU did not help. I will say that on the XP computer I am using USB2 (no native USB3 support), but I even eliminated a USB host controller chip by moving to a USB port supported by another USB2 controller.

Anyone seen this before?

 

[BarkingGhostar]

I am so glad no one else on AT isn't having this issue.

I bought an SIIG USB3 controller (TI chipset) and installed it into the XP computer, and then tested it with the working MBE drive. As predicted, it worked just fine. Connected the "I don't wanna work on XP" MBE and this time the computer POST'd and booted just fine, but still its as if I had not connected this second MBE.

I played musical USB3 ports, disconnected all other USB devices (accept KBM) and no dice. Something about this particular MBE seems to only want to work in W7 and not XP. I'm beginning to wonder if two MBE drives can only be used in Vista/W7/8 environments.

 

[imagoon]

Doesn't xp have a 2TB limit with MBR? If this is XP64 I think it can use GUID. Maybe one drive is GUID and the other is MBR? Or XP is seeing the protective MBR and opening one of the disks. The final cut off is some where around 2.19 TB. Is one of the 2 drive above that in total disk space used?

 

[BarkingGhostar]

Ok, I found out what is going on. When you connect a 3TB MBE to a Windows computer for the first time out of the box it determines what OS you are using. If it is XP it creates a monolithic partition based on 4096 sectors and is identified as a MBR style partition.

On the other hand, if you connect it to Vista or above it will create a monolithic partition using the GPT and not the MBR. So, if out of the box you first connect it to a W7 it will be GPT and as a result stay that way, and unreadable, when connected to an XP PC thereafter.