計(jì)算機(jī)網(wǎng)絡(luò)與因特網(wǎng)課件(已修改)
2025-04-23 22:10 本頁面
【正文】 Computer Networks and Inters 《 計(jì)算機(jī)網(wǎng)絡(luò)與因特網(wǎng) 》 課件 PART IV Network Applications Chapter 27 The Socket Interface Socket 接口 Introduction The interface between an application and protocol software. How an application uses protocol software to munication. Set of procedures that an application uses to bee a client or a server, to contact a remote destination, or to transfer data. Application Program Interface Client and server application use transport protocols to municate. The interface an application uses when it interacts with transport protocol software is known as an Application Program Interface (API). An API defines a set of operations that an application can perform when interacting with protocol software, the API determines the functionality that is available. The Socket API Although protocol standards allow operating system designers to choose an API, many have adopted the Socket API. The Socket API is available for many operating systems. The Socket API originated as part of the BSD Unix operating system. The Socket API is a de facto standard. Sockets And Socket Libraries In BSD Unix and the system derived from it,socket functions are part of the operating system itself. In many cases,instead of modifying their basic operating system,vendors created a socket library that provides the Socket API. A socket library can provide applications with a socket API on a puter system that does not provide native sockets. When an application calls one of the socket procedures, control passes to a library routine that makes one or more calls to the underlying operating system to implement the socket function. Socket Communication And Unix I/O An application municates through a socket similar to the way the application transfers data to or from a file. Unix uses an openreadwriteclose paradigm for all I/o 補(bǔ)充： 1. Socket API與 Unix Unix是一個(gè)通用的交互式多用戶分時(shí)操作系統(tǒng)。 Unix由 ATamp。T 公司 Bell實(shí)驗(yàn)室于 1969年開發(fā)。 Unix 有兩個(gè)主要的流派： System V 和 BSD System V 由最初的 ATamp。T Unix 演化而來。 BSD Unix 是由加州大學(xué)伯克利 (Berkeley) 分校開發(fā)，其目標(biāo)是提供一個(gè)具有復(fù)雜網(wǎng)絡(luò)支持的開放系統(tǒng)。 TCP/IP 協(xié)議族也與 Unix 的發(fā)展有很密切關(guān)系。 Socket API與 Unix 操作系統(tǒng)關(guān)系非常密切。 UNIX系統(tǒng)的 I/O命令集，其模式為打開一讀 /寫一關(guān)閉（ openwritereadclose）。 在一個(gè)用戶進(jìn)程進(jìn)行 I/O操作時(shí)，它首先調(diào)用“打開”獲得對指定文件或設(shè)備的使用權(quán)，并返回稱為文件描述符的整型數(shù)，以描述用戶在打開的文件或設(shè)備上進(jìn)行 I/O操作的進(jìn)程。 然后這個(gè)用戶進(jìn)程多次調(diào)用“讀 /寫”以傳輸數(shù)據(jù)。 當(dāng)所有的傳輸操作完成后，用戶進(jìn)程關(guān)閉調(diào)用，通知操作系統(tǒng)已經(jīng)完成了對某對象的使用。 TCP/IP協(xié)議被集成到 UNIX內(nèi)核中時(shí)，相當(dāng)于在 U
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