thank you so much for this info.
but i need help from you please
i,m working in saftey and security systems company and i,m new in this field

there is a type pf server for scanning machine like this machine in airport
i need to know the hard ware peaces of this server like no. of slot, floppy disk support, HDD support ,power supply support and sheet metal...etc like that
so if any one can help me how i can choose good type of server and whats advantages and disadvatages
thank you for all