# Server Message Block

> network communication protocol for providing shared access to resources

**Wikidata**: [Q857655](https://www.wikidata.org/wiki/Q857655)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Server_Message_Block)  
**Source**: https://4ort.xyz/entity/server-message-block

## Summary
Server Message Block (SMB) is a network communication protocol designed to provide shared access to files, printers, and other resources on a network. Developed by Microsoft, it functions as a network file system that allows a computer to access files on a remote machine as if they were stored on a local drive.

## Key Facts
- **Classification:** Computer network protocol and network file system.
- **Developer:** Microsoft Corporation.
- **Aliases:** Common Internet File System (CIFS), Smbfs, NetBIOS-Protokoll, and LanManager-Protokoll.
- **URI Scheme:** Officially assigned as `smb` by IANA.
- **Core Components:** Includes the Common Internet File System (CIFS) as a part of the protocol suite.
- **Documentation:** Defined by Microsoft Open Specifications including [MS-SMB], [MS-SMB2] (Versions 2 and 3), and [MS-SMBD].
- **Usage:** Primarily utilized by "SMB shares" to provide remote resource access.
- **Related Class:** Network file systems, which enable remote file operations to mirror local file system behavior.

## FAQs
### Q: Who developed the Server Message Block protocol?
A: SMB was developed by Microsoft, an American multinational technology corporation founded in April 1975 and headquartered in Redmond, Washington.

### Q: What is the difference between SMB and CIFS?
A: Common Internet File System (CIFS) is a part of the Server Message Block protocol; the terms are often used as aliases for one another in various technical contexts.

### Q: What are the current versions of the SMB protocol?
A: The protocol has evolved through several iterations, with current documentation covering the original SMB ([MS-SMB]) as well as SMB Versions 2 and 3 ([MS-SMB2]).

### Q: Does SMB support high-performance data transfers?
A: Yes, the protocol includes [MS-SMBD], which is the SMB2 Remote Direct Memory Access (RDMA) Transport Protocol designed for high-speed data movement.

## Why It Matters
Server Message Block (SMB) is a foundational technology for network interoperability and resource sharing. By providing a standardized way for computers to communicate with remote servers, it enables the "network file system" model where remote resources are treated as local assets. This is critical for corporate environments where centralized file storage and "SMB shares" are standard for collaboration.

The protocol's significance is underscored by its stewardship by Microsoft, a dominant force in the software and technology industries with over 221,000 employees as of 2022. SMB has moved beyond simple file sharing to include sophisticated features like Remote Direct Memory Access (RDMA), ensuring it meets the performance demands of modern data centers. Its inclusion in the Microsoft Open Specification Promise allows for broad documentation and implementation across different platforms, making it a near-universal standard for network-based resource access.

## Notable For
- **Microsoft Open Specification:** The protocol is extensively documented under the Microsoft Open Specification Promise, ensuring technical transparency for versions 1, 2, and 3.
- **RDMA Support:** It features a specialized transport protocol ([MS-SMBD]) specifically for Remote Direct Memory Access to enhance performance.
- **Universal URI Scheme:** It is recognized by a dedicated uniform resource identifier scheme (`smb`), facilitating standardized network addressing.
- **Global Aliases:** The protocol is recognized globally under various names, including "서버 메시지 블럭" in Korean and "服务器消息区块" in Chinese.

## Body

### Protocol Classification and Function
Server Message Block is categorized as a computer network protocol and a network file system. Its primary purpose is to provide shared access to resources—such as files and printers—across a network. As a network file system, it allows a client machine to perform file operations on a remote server as if those files were residing on the client's local storage.

### Development and Specifications
The protocol was developed by Microsoft. It is maintained through several key specifications:
*   **[MS-SMB]:** The primary specification for the Server Message Block Protocol.
*   **[MS-SMB2]:** The specification covering Server Message Block Protocol Versions 2 and 3.
*   **[MS-SMBD]:** The SMB2 Remote Direct Memory Access (RDMA) Transport Protocol, which optimizes data transfer speeds.

### Components and Implementation
A significant component of SMB is the Common Internet File System (CIFS), which is listed as a part of the protocol and often serves as an alias. In practical application, the protocol is the underlying technology for "SMB shares," the standard method for sharing directories over a local area network (LAN).

### Technical Identifiers and Documentation
SMB is identified in various global knowledge bases and technical repositories:
*   **URI Scheme:** `smb` (registered with IANA).
*   **Knowledge Graph IDs:** /m/01z41f (Freebase) and ServerMessageBlockProtocol (KBpedia).
*   **Developer Resources:** It is a recognized tag on Stack Overflow and is documented at length on the Microsoft Docs platform under the Open Specification Promise.

## References

1. Freebase Data Dumps. 2013
2. [Source](https://www.iana.org/assignments/uri-schemes/prov/smb)
3. KBpedia
4. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)