the sme7 is supported the sata controller, right?
There is not "the" SATA controller, but a variety of different controllers, so I cannot confirm, that every SATA controller is supported by SME 7.
what does it mean for alpha version? can this alpha version install on intel pentium 4 pc and as well as the AMD processor? or does it need an alpha pc to run it?
Alpha means Pre-Beta in this case, but since there is already a SME 7 Beta 4, this should not affect your decision to try SME7 anymore.
what is the kernel version using by sme7? what is centos? if so, why use centos? is it a better solution as compared to the earlier developed?
uname -a says: Linux 2.6.9-11EL
CentOS is a free clone of Redhat Enterprise server.
And yes, since you can use S-ATA controllers and other new hardware now, it IS better, isn't it?