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MAKING THE CHANGE

From Standalone to Internet Appliance
by Edward Steinfeld

Start ý Internet Appliance Options ý Web Technology ý Cost and Options ý Web Server Inside ý Use Common Components ý Sources and PDF

COST AND OPTIONS

Web technology software costs much less than expected. The software tools and application code to develop a complete web-enabled device with e-mail cost $50,000 or less. Most embedded web-server software is licensed without run-time royalty fees.

One of the best advantages of using web technology is that there is no user software to distribute, no new software for a different connected platform, and no tracking of users. And, all of your customers are probably familiar with web browser use, so training is minimal.

Embedded web servers come in versions from minimal servers to full-featured servers. The amount of memory required by the server varies according to feature sets. Most projects will migrate to a more full-featured server. The additional cost and hardware support is not significant.

Usually, e-mail isn't considered. Web server vendors can elaborate on the possibilities and the advantages gained from having e-mail added. Some embedded web servers support DNS and XML parsing and framing. The additional memory needed for each of these options varies from 5ý20 KB of ROM, plus 5ý10 KB of RAM.

Allegro offers a run-time HTML parser (SoftPages) that permits end users to design their own front panel for the Internet appliance. Customers can create the display that meets their needs and customize it with their own logo. All the vendor does is provide the customer with the variable names and formats that are used inside the instrument. Having a run-time HTML parser could provide the instrument manufacturer with a new source of revenueýwriting custom pages for their customers.

A popular add-on is the RomMailer e-mail client. This makes the appliance proactive. The instrument can send e-mail as an alert or notification of needed service. The RomXML parser or framer can give the appliance a state-of-the-art method of sending and receiving data. It can parse XML-formatted data and pass the information to C programming constructs.

Any of these functions can be used individually or collectively. Web technology is a menu of features where the user can select any combination and be reasonably sure their choices will cooperate.

Other vendors with similar products include Treck, which provides the TCP/IP stack and the web server Phar Lap Software with its proprietary Win32 RTOS, and TCP/IP stack and web server Spyglass with both a web server and web browser, plus others. Go to the Internet World web site for a partial list and comparison of available web servers.

Table 1 is an overview of the Internet functions that can be added along with memory requirements. I am using products supplied by Allegro Software Development, but you can get them from other vendors with similar parameters.

INTERNAL COMPUTING POWER

Most instruments that are candidates for becoming Internet appliances are complex and based on a microcomputer chip. Whether that chip is 8-bit, 16-bit, or more powerful is not a problem. If the microcomputer chip can support the network protocol, it can support the web technology software that will make the instrument into an Internet appliance. Some vendors use the 8051 microcontroller, but typically an 80186 or one of the many 32-bit processor chips is used. Ask the TCP/IP software vendors whether or not their software will run on the microprocessor chip used in the instrument.

I am assuming that there is a microcomputer powerful enough to do the job and that the necessary network interface hardware is being used. The network hardware can be either a serial port or an Ethernet connection. A serial port is less desirable because it requires the instrument to have an external modem or external network server.

If youýre planning to design an instrument from scratch, consider using microprocessors from companies like Connect One or NetSilicon. These chip vendors include some of the network and web software as part of their microprocessors.

NETWORK INTERFACE

If the instrument is equipped with a serial port, it may be used to connect to an external web server. From there, the instrument functions can be made available to other machines on the network.

Many companies manufactur these small web servers. One of the earliest small, portable web servers came from Dawning Technologies, Inc. of Fairport, NY. As with most external servers, the instrument manufacturer must write software that communicates with the instrument, as well as design the pages that are used to control and monitor the instrument.

The advantage of this solution is that the instrument manufacturer does not have to modify the existing product to make it into an Internet device. The disadvantage is that both the cost of the external hardware and the user are limited to what functionality is available through the serial port. The hardware cost difference is similar to the cost difference between an internal and external data/fax modem for a PC.

This is a good solution when connecting a third-party instrument to the network. The solution is limited to the functions the third party provides through the serial port.

Most instruments designed in the past few years have a network connection, usually Ethernet and TCP/IP. The idea for these instruments is that data can be sent to external computers for further processing and storage. The setup of the instrument usually cannot be done across the network.

With basic network functions built in, the only piece missing to become an Internet appliance is the embedded web server. The end user may need additional ROM and RAM, but I assume that most instruments have a surplus of memory or the ability to exchange the memory chips with those of greater capacity without a redesign.

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