第一至三段：
「The Greek Myths tell of creatures plucked from the surface of the Earth and enshrined as constellations in the night sky. Something similar is happening today in the world of computing. Data and programs are being swept up from desktop PCs and corporate server rooms and installed in “the compute cloud.”
Whether it’s called cloud computing or on-demand computing, software as a service, or the Internet as platform, the common element is a shift in the geography of computation. When you create a spreadsheet with the Google Docs service, major components of the software reside on unseen computers, whereabouts unknown, possibly scattered across continents.
The shift from locally installed programs to cloud computing is just getting under way in earnest. Shrink-wrap software still dominates the market and is not about to disappear, but the focus of innovation indeed seems to be ascending into the clouds. Some substantial fraction of computing activity is migrating away from the desktop and the corporate server room. The change will affect all levels of the computational ecosystem, from casual user to software developer, IT manager, even
hardware manufacturer.」
第四段：
「In a sense, what we’re seeing now is the second coming of cloud computing. Almost 50 years ago a similar transformation came with the creation of service bureaus and time-sharing systems that provided access to computing machinery for users who lacked a mainframe in a glass-walled room down the hall. A typical time-sharing service had a hub-and-spoke configuration. Individual users at terminals communicated over telephone lines with a central site where all the computing was done.」
第五至六段：
「When personal computers arrived in the 1980s, part of their appeal was the promise of “liberating” programs and data from the central computing center. ( Ted Nelson, the prophet of hypertext, published a book titled Computer Lib/Dream Machines in 1974.) Individuals were free to control their own computing environment, choosing software to suit their needs and customizing systems to their tastes.
But PCs in isolation had an obvious weakness: In many cases the Sneakernet was the primary means of collaboration and sharing. The client-server model introduced in the 1980s offered a central repository for shared data while personal computers and workstations replaced terminals, allowing individuals to run programs locally.」
第七段：
「In the current trend, the locus of computation is shifting again, with functions migrating outward to distant data centers reached through the Internet. The new regime is not quite a return to the hub-and-spoke topology of time-sharing systems, if only because there is no hub. A client computer on the Internet can communicate with many servers at the same time, some of which may also be exchanging information among themselves. However, even if we are not returning to the architecture of time-sharing systems, the sudden stylishness of the cloud paradigm marks the reversal of a long-standing trend. Where end users and corporate IT managers once squabbled over possession of computing resources, both sides are now willing to surrender a large measure of control to third-party service providers. What brought about this change in attitude?」
第八段：
「For the individual, total control comes at a price. Software must be installed and configured, then updated with each new release. The computational infrastructure of operating systems and low-level utilities must be maintained. Every update to the operating system sets off a cascade of subsequent revisions to other programs. Outsourcing computation to an Internet service eliminates nearly all these concerns. Cloud computing also offers end users advantages in terms of mobility and collaboration.」
第九段：
「For software vendors who have shifted their operations into the cloud, the incentives are similar to those motivating end users. Software sold or licensed as a product to be installed on the user’s hardware must be able to cope with a baffling variety of operating environments. In contrast, software offered as an Internet-based service can be developed, tested, and run on a computing platform of the vendor’s choosing. Updates and bug fixes are deployed in minutes. (But the challenges of diversity don’t entirely disappear; the serverside software must be able to interact with a variety of clients.)」
第十段：
「Although the new model of Internet computing has neither hub nor spokes, it still has a core and a fringe. The aim is to concentrate computation and storage in the core, where highperformance machines are linked by high-bandwidth connections, and all of these resources are carefully managed. At the fringe are the end users making the requests that initiate computations and who receive the results.」
第十一至十二段：
「Although the future of cloud computing is less than clear, a few examples of present practice suggest likely directions:
WordStar for the Web. The kinds of productivity applications that first attracted people to personal computers 30 years ago are now appearing as software services. The Google Docs programs are an example, including a word processor, a spreadsheet, and a tool for creating PowerPoint-like presentations. Another undertaking of this kind is Buzzword, a Web-based word processor acquired by Adobe Systems in 2007. Another recent Adobe product is Photoshop Express, which has turned the well-known image-manipulation program into an online service.」
第十三段：
「Enterprise computing in the cloud. Software for major business applications (such as customer support, sales, and marketing) has generally been run on corporate servers, but several companies now provide it as an on-demand service. The first was Salesforce.com, founded in 1999, offering a suite of online programs for customer relationship management and other businessoriented tasks; the company’s slogan is “No software!”」
第十四段：
「Cloudy infrastructure. It’s all very well to outsource the chore of building and maintaining a data center, but someone must still supply that infrastructure. Amazon.com has moved into this niche of the Internet ecosystem. Amazon Web Services offers data storage priced by the gigabyte-month and computing capacity by the CPU-hour. Both kinds of resources expand and contract according to need. IBM has announced plans for the “Blue Cloud” infrastructure. And Google is testing the App Engine, which provides hosting on Google server farms and a software environment centered on the Python programming language and the Bigtable distributed storage system.」
