ness model. Both offer plumbing that enables companies to build applications. Both are
designed for computer-to-computer interactions and so have no advertising model—
because there are no eyeballs involved in the interactions. It is up to the companies to
invent business models that can leverage the Web-services plumbing.
Web services reduce the costs of publishing and receiving information. Today, many
services offer information as HTML pages on the Internet. This is convenient for people,
but programs must resort to screen-scraping to extract the information from the display.
If an application wants to send information to another application, it is very convenient
to have an information-structuring model—an object model—that allows the sender
to point to an object (an array, a structure, or a more complex class) and simply send
it. The object then “appears” in the address space of the destination application. All
the gunk of packaging (serializing) the object, transporting it, and then unpacking it is
hidden from sender and receiver. Web services provide this send-an-object / get-an-object
model. These tools dramatically reduce the programming and management costs of
publishing and receiving information.
So Web services are an enabling technology to reduce data interchange costs. EDI
(Electronic Data Interchange) services have been built from the very primitive base of
ASN. 1. With XML and Web services, EDI message formats and protocols can be defined
in much more concise languages such as XML, C#, or Java. Once defined, these interfaces are automatically implemented on all platforms. This dramatically reduces transaction costs. Service providers such as Google, Inktomi, Yahoo!, and Hotmail can provide
a Web-services interface that others can integrate or aggregate into a personalized
digital dashboard and earn revenue from this very convenient and inexpensive service.
Many organizations want to publish their information. The World Wide Telescope is
one example, 3 but the example is repeated in biology, the social sciences, and the arts.
Web services and intelligent user tools are a big advance over publishing a file with no
schema (e.g., using FTP).
Grid computing and computing-on-demand enable applications that are mobile and
that can be provisioned on demand. What tasks are mobile and can be dynamically provisioned? Any purely computation task is mobile if it is written in a portable language
and uses only portable interfaces—WORA (write once run anywhere). Cobol and Java
promise WORA. Cobol and Java users can attest that WORA is difficult to achieve, but
for the purposes of this discussion, let’s assume that it is a solved problem. Then, the
What are the economic issues of moving a task from one computer to another or from one place
A computation task has four characteristic demands:
• Networking. Delivering questions and answers.
• Computation. Transforming information to produce new information.
• Database access. Access to reference information needed by the computation.
• Database storage. Long-term storage of information (needed for later access).
The ratios among these quantities and their relative costs are pivotal. It is fine to
send a gigabyte over the network if it saves years of computation, but it is not economic
to send a kilobyte question if the answer could be computed locally in a second.