<protocol> (SMB) A client/server protocol that provides file and printer sharing between computers. In addition SMB can share serial ports and communications abstractions such as named pipes and mail slots. SMB is similar to {remote procedure call} (RPC) specialised for file system access. SMB was developed by Intel, Microsoft, and IBM in the early 1980s. It has also had input from Xerox and 3Com. It is the native method of file and print sharing for Microsoft operating systems; where it is called {Microsoft Networking}. Windows for Workgroups, Windows 95, and Windows NT all include SMB clients and servers. SMB is also used by OS/2, Lan Manager and Banyan Vines. There are SMB servers and clients for Unix, for example Samba and smbclient. SMB is a presentation layer protocol structured as a large set of commands (Server Message Blocks). There are commands to support file sharing, printer sharing, {user authentication}, resource browsing, and other miscellaneous functions. As clients and servers may implement different versions ("dialects") of the protocol they negotiate before starting a session. The redirector packages SMB requests into a {network control block} (NBC) structure that can be sent across the network to a remote device. SMB originally ran on top of the lower level protocols NetBEUI and NetBIOS, but now typically runs over TCP/IP. Microsoft have developed an extended version of SMB for the Internet, the Common Internet File System (CIFS), which in most cases replaces SMB. CIFS runs only runs over TCP/IP. {Just what is SMB? (http://samba.anu.edu.au/cifs/docs/what-is-smb.html)}. {IBM protocols (http://protocols.com/pbook/ibm.htm)}. {Microsoft SMB/CIFS documents (ftp://ftp.microsoft.com/developr/drg/CIFS/)}. (1999-08-08)

Server Message Block (SMB) is a communication protocol originally developed in 1983 by Barry A. Feigenbaum at IBM and intended to provide shared access to files and printers across nodes on a network of systems running IBM's OS/2.

One of the two techniques for communicating between parallel processes (the other being shared memory). A common use of message passing is for communication in a parallel computer. A process running on one processor may send a message to a process running on the same processor or another. The actual transmission of the message is usually handled by the run-time support of the language in which the processes are written, or by the operating system. Message passing scales better than shared memory, which is generally used in computers with relatively few processors. This is because the total communications bandwidth usually increases with the number of processors. A message passing system provides primitives for sending and receiving messages. These primitives may by either synchronous or asynchronous or both. A synchronous send will not complete (will not allow the sender to proceed) until the receiving process has received the message. This allows the sender to know whether the message was received successfully or not (like when you speak to someone on the telephone). An asynchronous send simply queues the message for transmission without waiting for it to be received (like posting a letter). A synchronous receive primitive will wait until there is a message to read whereas an asynchronous receive will return immediately, either with a message or to say that no message has arrived. Messages may be sent to a named process or to a named mailbox which may be readable by one or many processes. Transmission involves determining the location of the recipient and then choosing a route to reach that location. The message may be transmitted in one go or may be split into packets which are transmitted independently (e.g. using wormhole routing) and reassembled at the receiver. The message passing system must ensure that sufficient memory is available to buffer the message at its destination and at intermediate nodes. Messages may be typed or untyped at the programming language level. They may have a priority, allowing the receiver to read the highest priority messages first. Some message passing computers are the {MIT J-Machine (http://ai.mit.edu/projects/cva/cva_j_machine.html)}, the {Illinois Concert Project (http://www-csag.cs.uiuc.edu/projects/concert.html)} and transputer-based systems. Object-oriented programming uses message passing between objects as a metaphor for procedure call. (1994-11-11)