什麼是區域網
區域網指有限區域(如辦公室或樓層)內的多臺計算機通過共享的傳輸介質互連，所組成的封閉網路。接下來小編為大家整理了什麼是區域網，希望對你有幫助哦!
There are two categories of networks: local area networks (LANs) and wide area networks (WANs). Here I'd like to mainly talk about LAN.
A LAN is a system of computers and associated peripherals such as Printers that are physically connected by cable within a limited geographical area-typically in an office building or on a college campus. The topology of the network may be ring, star or bus. LANs use fiber optics or coaxial cable to connect computers, and each computer must have special communications software installed oil its hard disk. Software has been developed that allows computers with different platforms to coexist and exchange data on the same LAN.
The LAN Operating System——Net Ware
Novell's Net ware has become the strongest competitor to IBM's own network operating environment and predates IBM in its support for LANs. In fact,IBM now markets Net ware for both the PC Network and for Token Ring in addition to its own key to Net ware is the file server software and directories on the server are mapped to network drives, thus operating like virtual diskettes from a user's perspective. The server software is a multitasking operating system with a file structure consistent with DOS 2.x and DOS 3.x. The Net ware shell in each workstation intercepts 21H DOS calls and redirects appropriate calls to the server.
Perhaps the primary advantage of Net ware is that it runs on a wide variety of networking rdless of whether you choose an IBM network, Corvus OMNINET, AT&T Star LAN, etc., you can obtain Net ware as the operating environment. In fact, if you have one of each the user will not be able to tell the difference(unless there are some distinct performance differentials), and they can be interconnected through Novell's system of bridges and gateways.
A File Server
Many networks are managed by a computer called a file server.A file server has a large-capacity hard disk and special software that manages access to flies on the network. It controls how data and database are shared among users on the network and how users access master copies of data and application software on the centralized hard disk. It is the file server's job to make sure that users don't accidentally try to update a file at the same time and scramble the data. The file server may also manage the access to an expensive piece of hardware such as a laser printer.
When a file server is used on a LAN, large databases are stored on the server and users may store all of their work flies there as operation is analogous to someone's manually collecting all the data each day placing them in a file drawer, and then redistributing these data to the workers as needed.
區域網
網路有兩類：區域網(LANs)和廣域網(WAN)。在這裡主要談一下區域網。
區域網就是在一個有限的地域範圍內，典型的如在辦公大樓或校園中，將計算機及相關外設(如列印機)用電纜進行物理連結而組成的一個系統。網路的拓撲結構可以是環形的、星形的或匯流排形的。在區域網中，可用光纖或同軸電纜連結多臺計算機，且每臺計算機的硬碟上必須裝有專門的通訊軟體。允許具有不同平臺的計算機共存於同一區域網中，且能進行資料交換的軟體早已開發出來了。
局域網路作業系統——Net ware
Novell公司的Net ware作業系統已經成為IBM公司特有的網路操作環境最強有力的競爭對手，它在對區域網絡的支援方面也早於IBM公司。事實上，除了自己的一部分軟體外，IBM公司也為所有的PC網和令牌環網購買了Net ware作業系統。Net ware 作業系統的最主要部分是檔案伺服器軟體，伺服器上的目錄被對映到網路驅動器，這樣在使用者看來，它執行起來就如同是虛擬磁碟。它的伺服器軟體是一個多工的作業系統，檔案結構也與
DOS 2.x和DOS 3.x的檔案結構一致。工作站上的 Net ware外殼程式攔截了DOS的21H中斷，並重新走向為對伺服器的呼叫。
Net ware作業系統的主要優點是能夠執行在多種網路硬體上。不論是選擇IBM網路，Corvus公司的OMNINET網路，還是AT&T公司的星形區域網絡等，都可獲得Net ware的操作環境。
檔案伺服器
許多網路由一稱為檔案伺服器的計算機來管理。檔案伺服器具有大容量的硬碟和一些用來管理對網上檔案訪問的專門軟體。它控制著網上使用者如何共享資料和資料庫，以及使用者如何存取中央硬碟上的資料和應用軟體的主拷備。確保兩個使用者不能偶然地在同一時刻對同一檔案進行更新或爭奪資料也是檔案伺服器的工作。檔案伺服器還可以管理對昂貴硬體(如鐳射印表機)的訪問。
當檔案伺服器用於區域網時，大型資料庫就被儲存在伺服器上，而且使用者也可以將其所有的工作檔案存放在上面。這就像是一個人每天手工收集所有的資料，放到一檔案抽屜中，然後等需要時，再將這些資料發到工作人員手中。
