工程工作站外文翻譯@中英文翻譯@外文文獻翻譯

附件 1：外文資料翻譯譯文 工程工作站 就原始性能而言 ,工程工作站大體上介于 PC 機和大的小型機之間 ；盡管隨著 PC機和工作站兩者功能的不斷增強 ,這三者之間上的差別越來越難以分清了。但是，工程工作站不論同 PC 機，或是同傳統(tǒng)的分時共享技術（或稱小型機技術）相比確實有幾個優(yōu)點。 跟 PC 機相比，工作站通常具有更多的功能強的 CPU，而且能夠支持更多的主存，盡管 PC 機在功能上同低檔工作站有重疊現(xiàn)象。同 PC 機不同的是，工作站能夠提供多用戶，多任務操作系統(tǒng)，這已成為它的一種標準特點。 OS/2 和 UNIX 可用于 PC 機，尤其是以 Intel80386 為基礎的 PC 機。然而， PC 機用得最多的操作系統(tǒng)仍是 MSDOS。 多任務系統(tǒng)同單任務系統(tǒng)相比有幾個優(yōu)點。首先，用戶可同時運行多道程序，因此對于應用程序是透明的。雖然 PC 機的臺式附件和常駐 RAM 程序可給用戶提供某種原始的多任務功能，足以運行后臺打印假脫機程序以及諸如此類的程序。但是，他們對應用程序可能是不透明的，而且不能提供像過程間通信和支持多個并行用戶這樣的重要特點。 對于當今的工程應用來說，也許更為重要的是 PC 機上缺少大容量的物理內存和虛擬內存。對于大型應用程序而言，虛擬存儲器是很重要的 ，因為數(shù)據(jù)組太長，這種大型應用程序簡直不能全部在物理存儲器內運行。要是沒有虛擬內存的話，像編輯大型文件之類的簡單任務都會慢的令人頭疼，甚至不可能完成。加上，許多應用程序更加復雜，因為它們必須緩沖數(shù)據(jù)或采用覆蓋方式將應用程序的不同部分分頁從物理內存中調進調出。 最后，大多數(shù)工作站的用戶接口要比大多數(shù) PC 機的用戶接口高級一個明顯的例外情形是 Macintosh 蘋果機上的用戶接口。計算機的用戶接口。計算機的用戶接口和連接它的可編程接口決定了應用程序接口的高級程度。強有力的開發(fā)手段可讓程序員創(chuàng)建直觀的用戶接口。 雖然 工作站比 PC 機功能強，但跟現(xiàn)代小型機例如數(shù)字設備公司（ DEC） VAX8000 系列的小型機相比，情況通常就不是那樣了?？墒?，工作站比起小型機來確有一些優(yōu)點。 比起小型機來，工程工作站通?？蔀槊總€用戶提供更多的 CPU 功能，更優(yōu)越的價格 性能比以及更可預測的響應時間，因為 CPU 通常是為單個用戶服務的。工作站的用戶接口，常常像它勝過多數(shù) PC 機的用戶接口一樣，也勝過小型機。不過，隨著 X 窗口系統(tǒng)以及支持 X 協(xié)議的廉價終端設備的出現(xiàn)，這種優(yōu)勢正在消失。 網(wǎng)絡系統(tǒng)的問題 雖然工作站給工程師帶來新發(fā)現(xiàn)的計算機功能和顯示能力， 但并非一切都是完美的。在擁有不少工作站的場所，從用戶和系統(tǒng)管理人員的角度看來，問題是顯而易見的。工作站操作系統(tǒng)的復雜性接近或超過了僅在幾年前小型計算機操作系統(tǒng)的。在幾乎沒有軟件可用來使下述重要任務例如磁盤支持，軟件安裝和更換，網(wǎng)絡管理或帳戶管理等實現(xiàn)自動化的情況下，要對這樣一種系統(tǒng)進行管理可能前景暗淡。 分布式文件系統(tǒng)能對當?shù)鼐W(wǎng)絡上的許多計算機產生從未預料到的依賴性。如果文件服務盤出現(xiàn)故障，許多計算機機器用戶都可能受到影響。如果在不同計算機的過程間用文件進行通信的話，隱含目錄也可能給兩臺計算機間生成全局文件 系統(tǒng)造成矛盾。 除了管理分布式系統(tǒng)根深蒂固的問題之外，還有獲取軟件許可證的費用過高的問題。由于工作站的大多數(shù)軟件仍要像用在小型機和主機上那樣獲取許可證，對許多機構來說，這筆費用已經高到難以承受的程度。一些機構已開始提出對大量計算機的管理問題以及軟件許可證的問題，但當前的解決方法 還不多。 工作站的未來發(fā)展方向 在短暫的發(fā)展過程中，工作站技術已經表明它的發(fā)展速度可以比其他任何現(xiàn)用計算機技術要快。在不遠的將來，這一趨勢大概不會改變。預計在將來的一段時間內， CPU 的運行速度會繼續(xù)大大提高。重要的工作站廠商都在 RISC（縮簡指令組計算機）技術上投入了巨額的資金，以便降低處理器芯片的復雜性并縮短其循環(huán)周期。大多數(shù) RISC 結構格式都設計成也能用于新的制造工藝例如射極耦合邏輯電路和砷化鎵制造技術，這就有希望在將來制造出比現(xiàn)在流行的速度更高得多的芯片來。 正如在有關硬件的那一節(jié)中提到的，浮點計算速度的提高一般地講并沒有能夠同步趕上 CPU 速度的提高。然而，下一代浮點處理器可能改變這種不合拍的情況。最近一些廠商已經研制出原性能達到浮點運算速度每秒 1000 到 3000 萬次的芯片。 開發(fā)應用者要做出的最困難決定之一是支持哪些工作站。從 傳統(tǒng)上看來，大多數(shù)應用的最不可移植部分一直是用戶接口，因為每一個廠商都有自己專有的窗口管理系統(tǒng)。隨著 X 窗口系統(tǒng)和 Sun 的 NeWS 系統(tǒng)的日益普及，這種情形正在發(fā)生變化。這兩個系統(tǒng)都是以網(wǎng)絡為基礎的窗口系統(tǒng)。 因此，能夠在合適的計算服務盤上運行計算密集的應用程序。有幾種用戶接口工具包適用于 X 系統(tǒng)，其中有許多都是不受專利限制的。所有的跡象都表明，應用軟件廠商的工作更容易，而且，歸根結底，提供給最終用戶的應用軟件會更好。 對分布式計算提供的支持比對分布式文件系統(tǒng)提供的支持落后得多。隨著市面上出售的專用計算機越來越多 ，工程師和計算機科學家將需要開發(fā)利用兩種或兩種以上的計算機的專門能力來求解日益復雜的問題。工作站將成為集成這些異質功能計算機的焦點。有些廠商已經在其系統(tǒng)中增加了遠程過程調用程序庫。有許多問題，例如平衡裝入，容錯，應用分區(qū)，動態(tài)服務盤定位，客戶登記以及數(shù)據(jù)加密等問題，目前還只能部分解決。 附件 2：外文原文（復印件） The Engineering Workstation Workstations fit somewhere between PCs and large minicomputer in terms of raw performance； although as both PCs and workstations get more powerful, the performance distinctions between the there groups are more difficult to make. Engineering Workstations do have several advantages over both PCs and traditional time-sharing or minicomputer technology, however. Workstation generally have more powerful CPUs and can support more main memory than PCs, although the latter overlap with low-end workstations in power. Workstations, unlike PCs, offer multitasking, multitasking operating systems as a standard feature. OS/2 and UNIX are available for PCs, especially for those based on the Intel 80386. However, the dominant operating system for PCs is still MS-DOS. Multitasking systems have several advantages over single-tasking systems. First, the user can run more than a single program at a time , transparent to the application. Desk accessories and RAM-resident programs on PCs give the user some primitive multitasking capability, sufficient to run background print spoolers and the like . However, they may not be transparent to application program, and they do not offer significant features like interprocess communication and support for multiple, simultaneous users. Perhaps more important for todays engineering applications is the lack of large physical and virtual memories on PCs. Virtual memory is important for large applications, many of which simply cannot be run entirely in physical memory because the data sets are too large, Without virtual memory, a simple task like editing a large file becomes tedious or even impossible to perform. In addition, many applications are more complex because they must buffer data or use overlays to page different parts of the application in and out of physical memory. Finally, the user interface of most workstations is more sophisticated than that on most PCs. The one notable exception is that of the Apple Macintosh. The computers user interface and the programming interface to it determine how sophisticated the applications program interfaces can be. Powerful development tools allow programmers to create intuitive user interfaces for complex applications. While workstations are typically more powerful than PCs, that is generally not the case when they are compared with modern minicomputers, such as those of the VAX-8oooseries by Digital Equipment Corporation(DEC). They do have several advantages over minicomputers, however. Engineering workstations generally provide more CPU power per user, a better price-performance ratio, and more predictable response times than minicomputers, because the CPU is usually devoted to a single user. Workstations often have the same user-interface advantages over minicomputers that they have over most PCs. With the advent of the X Window System and inexpensive terminals that support the X protocol, this advantage is disappearing. Problems with Networked Systems Although workstations are giving engineers new-found computer power and display capabilities, all is not perfect. The problems become readily apparent to users and system administrators at sites with more than a handful of workstations. The Complexity of the operating systems on workstations approaches or exceeds that of minicomputer operating systems of just a few years ago. With little or no software available to automate critical tasks such as disk backup, software installation and update, network management, or account management, the administration of such a system can become a nightmare. Distributed file systems can create unexpected dependencies on many machines on a local area network. When a file server goes down, many machines(and their user)may be affected. When files are used to communicate between processes on different machines, directory caching may create inconsistencies in the appearance of the global file system on the two machines as well. On top of the problems inherent in managing distributed systems are software licensing costs, which for many organizations have skyrocketed because most software packages for workstations are still licensed as if they were for minicomputer and mainframes. Some organizations are beginning to address the problems of administering large number of machines and software licensing but few solutions are today. Future Directions for Workstations During its brief history, workstation technology has shown that it can move faster than any other computer technology available. This will probably remain true for the future. Significant increases in CPU speeds are expected to continue for some time in the future. The major workstation vendors have all made a substantial investment in RISC(reduced-instruction-set computer)technology, thereby reducing the complexity and cycle time of processor Chips, Most RISC architectures are designed to be scalable to new fabrication technologies as well, such as emitter-coupled logic and gallium arsenide, promising even higher speed chips in the future than those prevalent today. As mentioned in the section on hardware, the increase in CPU speeds has not, in general, been matched by a parallel increase in floating-point computation speeds. However, the next generation of floating-point processors may performances. Recent developments by several vendors have led to chips with raw performances of between 10 and 30 million floating-point operations per second. One of the most difficult decisions for application developers to make is which workstations to support. Traditionally, the most nonportable part of most applications has been the user interface, since each vendor had a proprietary window-management system. This is starting to change as the X Window System and Suns NeWS gain in popularity. Both are network-based window system, so computer-intensive applications can be run on the appropriate computational se