I have acquired such a computer. It loads the BIOS properly, but I do not yet have a hard drive for it. I bought a 2.5" form factor hard disk drive, but it did not fit.
It seems to me that I must purchase an IDE HDD with a 1.8" form factor.
The document found at the following link seems to agree.
I have three questions :
1. Am I correct in supposing this?
5. What are the HDD specifications for the X40, Type 2386-KLU?
3. Do I need a special connector?
You really want to listen what others are telling you and avoid using a 4,500 drive like the ones supplied with it. They could take minutes to boot and were the single biggest cause those X4's are sold as "Like New" because users packed them in sock drawers never to be used again.
I've used ZiF PATA SSD's and CF/IDE adapters and barely found a signifnicate performance difference, an mTron Mobi is superbly fast but didn't perform much faster than a 300x Lexar in an Addonics or UXCELL CF/IDE adapter but did cost six times more.
since you're using an x40, you could use the dual addonics and simultaenously mount two cards for extra capacity, even a RAID array.
There is an enlighetneing thread at ThinkWiki http://www.thinkwiki.org/wiki/CompactFlash_boot_drive
along with the materials here that will help you decide.
My UDMA6 CF adapters consistenly outperfrom the Samsung SSD's which users have reported running at UDMA3.... it does make a difference when the bus speed is half and the Lenovo Samsung sells for hundreds $.