I’m trying to partition and format a new hard drive for my MacBook Pro that has Snow Leopard. Every time I try to format the drive, I get the error message: POSIX cannot allocate memory. How can I fix this problem?

Many times when this happens, the sata cable needs to be replaced.  The reason you’re getting the POSIX error is because the hard drive cannot communicate with the computer through the attached sata cable.  I had this same problem recently, and after I replaced the cable I was able to install a new hard drive, format it, and install Snow Leopard.  Now everything works fine.