What Is Winsock? All You Need To Know

Definição

Short for Windows Sockets API (WSA), Winsock is a supporting program and technical specification that determines how the Windows network software accesses network services in computing, especially TCP/IP. It deals with input and output requests for Internet applications in the Windows operating system.

It is adapted from Windows for the Berkeley Unix socket interface. That’s why it is called Winsock. The socket is a specific convention that connects two program processes and exchanges data across a network or within the same computer.

Background

The Windows Socket Project originated at the Birds Of A Feather conference on October 10, 1991, at Interop ’91 in San Jose in San Jose. It is based on socket specifications, which are created by NetManage. And it put these specifications into the public domain at this meeting.

The first edition of this specification was created by Martin Hall, Mark Towfiq of Microdyne, Geoff Arnold of Sun Microsystems, and Henry Sanders and J Allard of Microsoft, with assistance from many others.

There are some discussions on how best to solve intellectual property, copyright and potential antitrust issues, and consideration for working through IETF or founding a non-profit foundation. Finally, it was decided that the specification would consist of only five authors as individual copyrights.

For a long time, all participating developers rejected shortening the name to simple Winsock. Because, among users, there is a lot of confusion between the DLL library file (winsock.dll) and the API, while the DLL library file exposes only the common WSA interface to the application above. Users generally believe that full TCP/IP protocol support can solely be provided if they ensure that DLL files exist on the system.

Technology

The Winsock specification defines two interfaces: the API and the SPI. Application developers use the former, and the latter offers a way to add new protocol modules to the system for network software developers. Each interface represents a contract.

The API ensures that compliant applications will function properly, as implemented by a consistent protocol from any network software vendor. The SPI contract provides a protocol-compliant module that can be added to Windows and is therefore used by API – compliant applications.

The code and design of Windows socket are based on BSD sockets but offers additional features that allow API to conform to the general Windows programming model.

The Windows Socket API covers almost all the characteristics of the BSD socket API. However, some unavoidable obstacles stem primarily from the fundamental differences between Windows and Unix.

However, Windows sockets are designed to be relatively easy for developers to port socket-based applications from Unix to Windows. It is insufficient to create an API that only works for newly written Windows programs. As a result, Windows sockets contain many elements that are designed to be portable.

This is not possible in Windows, so Windows sockets introduce a particular function, WSAGetLastError(), to retrieve error messages. Though these mechanisms are helpful, application porting is still too complicated.

Many of the original TCP/IP applications were implemented using Unix-specific system features, which are problematic to reproduce in Windows.

Porting gives way to the development of dedicated Windows applications in a relatively short period.

Implementations

Microsoft Implementations

• Microsoft did not offer an implementation of Winsock 1.0.
• Version 1.1 of Winsock was available in the add-on package called Wolverine for Windows for Workgroups.
• Version 2.1 of Winsock was available in an add-on package for Windows 95.
• The latest versions of Winsock 2.x are delivered as part of service packs or with new Windows releases.
• Winsock 2 can be extended via a mechanism called a Layered Service Provider (LSP).

Other Implementations

• Other vendors offering Winsock-compliant TCP/IP and UDP/IP stacks include 3Com, DEC, Beame, and Whiteside, Distinctive, Frontier, IBM, FTP Software, NetManage, Novell, Sun Microsystems, Microdyne, and Trumpet Software International.
• Trumpet Winsock by Peter Tattam is one of the few Winsock 1.0 implementations installed under Windows 3.0, and this version does not have built-in support for Winsock.
• The Wine project involves the Winsock source and binary compatibility that is re-implemented on the BSD socket API.

Conclusão

The above introduces basic information about Winsock, including its definition, background, technology, and its implementations.