Concurrency Help

[Davidhere40]

I need a little help figuring out how to design my database/web
services for a bidding system. I'm not sure how to solve the problem
of concurrency. I'll give an analogous example of what the system is
supposed to do. In a nutshell, there are 10,000 computers with 10 gigs
of hard drive space each, which are sold to the highest bidder in 1
gig chunks. The bidder simply tells me how much they are willing to
spend and what state or country the computer should be located in. The
system should fill their order if they have the highest bid on a gig
with their criteria. How the hell do I assign those chunks to the
highest bidder efficiently. The problem with concurrency would be when
two or more people are getting data and submitting data at the same
time. If its not done synchronously or isn't thread safe, then the
amount of available space may be incorrectly read or written, for
example.

Is there a standard way to solve this type of database/web service
design problem?