About the Applet

• Why it's important
• What it is
• What it is not
• What systems resources it needs

Everyone who has tried to read an XPS spectrum generated by someone else's (different) data system on someone else's instrument will be aware of the potential difficulty of this apparently simple action. The ISO-14976 Standard Data Transfer Format (SDTF) seeks to alleviate these difficulties by providing an internationally agreed convention for data transfer which is both definitive and flexible, relatively easy to implement as a common mechanism for data input and output for most data systems, and incidentally, because it is a text based format, directly intelligible by eye.

The Java applet presented here take these principles of openness and accessibility a step further, providing an easily used viewer for the ISO format data which is available to the widest range of computer types in one of the most important communications environments - that of the world wide web. The applet addresses the problem of how to incorporate spectra which preserve all the original information content (rather than a part of it, as in bit map representations) for display within html based web pages.
The Java programming language has been chosen as the means of adding that functionality to the communications capability of the Internet because of its close approach to true platform independence - the ability to run an application on whatever size or type of computer system you happen to have - in other words to provide universal access.

Quite simply it is a spectrum display routine for XPS.

In its present form it does NOT display AES, SIMS, ISS or any other type of spectrum (although simple changes to the applet code would enable it to do so). The applet also translates only a single spectrum or spectrum region (the ISO-14976 format, like most commercial data systems, provides for multiple regions or spectra within the same data file).

The applet, then, provides a "window" into the whole of the "live" information in a spectrum for illustration and explanation purposes, so that web page authors now no longer have to rely on "static" pictures of parts of spectra.

Further applications of the routine do arise naturally from the environment and structure of the applet - spectrum interchange via e-mail as well as over the web, for example, as well as providing simple access to reference collections of data and other archives.

The applet is NOT a "data system"!

In its present form it provides only the most basic of display capability - that which is regarded as sufficient to show the simple signal content in an XPS spectrum.

It is NOT intended to replace commercial offerings, whether those are fully fledged instrument control and data collection systems or simply data processing or data conversion suites.

Bear in mind that the applet is NOT

• a rigorous ISO format checker,
• comprehensive,
• optimised for speed,
• optimised for efficient use of memory,
• finished(!)
  
or
• guaranteed to be bug free.

One other important thing - it's NOT available for sale,

- it's free!

Since you're reading this, you have at least two of the three key elements required -

    - a computer running
 

• some sort of connection to the Internet
  
and
• a web browser

 
The third and equally important element is

• Java "enabled" for your web browser

If you're unsure about whether Java is enabled or not, it may be best to consult your local system administrator - perhaps the more detailed explanation of what the system does and how it does it will help in that case.
 
If you're feeling experimental, however, continuing to the next page will soon settle the matter: if you see (eventually - it might take a minute or two to load) a live spectrum, then all is well: if you see a static graphic, then all still might be well, but Java might need to be enabled on your system (check your browser "preferences" settings - seek help if you're unsure).
Be advised though that this direct strategy could bring the wrath of hard-pressed "sysops" on your head if things go wrong....!

Remember that local memory requirements often increase substantially when the Java Virtual Machine is invoked (the most common cause of problems with the applet is running out of local memory). The amount of memory required depends strongly on the machine type and its operating system as well as the browser type, so it's difficult to give general guidelines of what to expect : a "Windows" type environment running one of the "standard" browsers should be able to perform in 32MB of main memory, however (unless other large applications are present). Remember also that repeated invocations of the applet - for example by "reloading" a containing html page do not necessarily shut down (unload) earlier versions until you "quit" the browser entirely, and so memory can be quickly consumed by this means. 

A Note on Printing: Remember that the Java code runs essentially separately from the browser and so printing the contents of the Java generated display inside the web page can give rise to problems on some systems (there is no provision for printing directly from the applet). Usually this means that the display is not printed at all, or that only the "static" parts (the buttons and controls) are printed (some systems have been reported as printing displays which are different from those on screen - e.g. without scale expansion). This is not the fault of the applet: most of the latest web browsers do handle printing in some fashion, but again it depends on the combination of the computer, operating system, and browser as to whether it works properly or not. Best advice is to install the most recent software possible, or if nothing else works, use some kind of "screen capture" program.

 

"Java", "HotJava" and the "coffee-cup" logo are trademarks of Sun Microsystems Inc. and acknowledged.

Copyright © Acolyte 1999 Last Update:00/01/24