Question

Could someone please explain the differences between POSIX sockets and BSD sockets?

Answer 1

As reported in http://www.openss7.org/papers/strsock/sockimp.pdf:

Berkeley Sockets. Sockets uses the BSD interface that was developed by
BBN for the TCP/IP protocol suite
under DARPA contract on 4.1aBSD and
released in 4.2BSD. BSD Sockets
provides a set of primary API
functions that are typically
implemented as system calls. The BSD
Sockets interface is non-standard,
operated differently from the POSIX
interface in subtle ways, and is now
deprecated in favour of the POSIX/SUS
standard Sockets interface.

POSIX Sockets. Sockets were standardized by X/Open, later the
OpenGroup, and IEEE in the POSIX
standardization process. They appear
in XNS 5.2 [XNS99], SUSv1 [SUS95],
SUSv2 [SUS98] and SUSv3 [SUS03].
POSIX/SUS Sockets is now the common
application environment for accessing
networking, deprecating the XTI for
TCP/IP networking applications.