At the risk of being labeled as a caller on the "Mr. Obvious" show, when you say, "WinXP does not support booting off GTP" you mean as a boot drive and not just in the chain of drives connected to the mobo, correct?"
Actually, Windows XP doesn't support GPT at all. Neither booting from it or reading and writing to it.http://en.wikipedia.org/wiki/GPT_Disk#W ... t_versionshttp://msdn.microsoft.com/en-us/library ... 4111922342
There is some confusion here in terminology. An aligned disk to support an Advanced Format
(which is a hardware change on the disk) is being mixed up with GPT, which is used to allow an operating system to see a disk larger than 2.2 TB (there are other advantages for smaller drives).
Windows XP disk tools don't support the alignment of partitions to best support the 512e Advanced Format. Windows Vista, 7, and 8 disk tools support alignment of the partitions to support the 512e Advanced Format. 512e is a backwards compatibility concession, so long as the partitioning software aligns the partition correctly the OS is left ignorant to the reality of the Advanced Format hardware beneath. Windows 8 is the only edition of Windows that understand the 4Kn Advanced Format that disk storage will one day adopt.
In short: all you need to do is use a partitioning utility that understands how to properly align a partition. Sounds like you've found a solution to that end.
My Gigabyte mobo has something like 8 SATA ports and 10 USB ports (plus a couple more). I think I've read that XP can handle as many drives as you throw at it - although it does have a 2.2TB partition limit - but, that doesn't mean that I could have 18 drives connected and running - overlooking the IDE support and DVD drive - If I wanted to, does it? I'm thinking no because of...IRQ limitations (although, don't expect me to explain this.)
You could have eighteen drives, yes. Technically more than that if you leveraged USB hubs. IRQs are no longer a relevant concern in modern computing. Each SATA controller leverages a single IRQ across the array of ports. USB shares a similar design in that the controller has a single IRQ across the array of ports.
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