|
heitml Technology
heitml takes advantage of the latest research into the design and
construction of High Level Language Compilers. Dr. Helmut Emmelman, the
designer, earned his a PhD from the University of Karlsruhe for his
ground-breaking work in the area of automatic code generators.
heitml uses high speed scanner and parser generators to analyze and
convert pages to HTML format in real time. These high speed techniques
make immediate processing of heitml pages possible at the very moment
a user requests a page, without delaying or significantly slowing down the
Web Server. Pages generated by heitml can be delivered to the User's
Browers with no noticeable delay.
heitml is internally pre-compiled for efficent execution.
Server Integration
Although heitml can use the slow CGI interface for compatibility
purposes, most Users will prefer using the version that directly integrates
with the Web Server.
On Windows NT, heitml uses the fast ISAPI interface.
This means heitml is directly linked to Microsoft's Internet Information Server
as though it was part of the original code. It operates in a re-entrant,
multi-threaded fashion, and can process several requests in parallel. Anyone
familiar with the history behind the development of WinNT will know that this
is the way Microsoft intended applications to be developed. Only now, however,
after years of availability, are applications like heitml being
created to take advantage of this WinNT feature.
On Unix, heitml can be linked directly to Apache, the most popular Web
Server software available for this Operating System. If you like, you can
read more about heitml and Apache here.
Multi Threading and Re-entrant Operation
The ISAPI version of heitml uses Windows NT threads to process User
requests in parallel. Using threads is far more efficient than launching
multiple processes (as CGI does). An additonal benefit of this approach is
that heitml has been written as a re-entrant (i.e. thread-safe) program.
Sessions
heitml is capable of remembering the values of variables from one page to
another. This makes it easy to keep track of anything a User requests
while he is logged onto your Site. So-called Session Variables such as these
can have any size. This means that large data structures such as Query Results
and the contents of Shopping Carts in Catalog Shopping Applications are easy to
keep track of. Using a special garbage collection scheme, heitml determines
(indepentent of User interaction) what data is needed by the next page. The maximum
number of Users and the expiration time of a Session is limited only by available
disk space.
Transaction Processing
There are various reasons why User Requests from Web Pages can lead to errors (e.g.
a network failure or a program bug) and there is no way to avoid every
possible error. With improper Transaction Processing methods, processes are
aborted unfinished, which can often leave both the Database and the
Session Variables in an inconsistent state. Naturally, this can have disasterous
effects. 
Effective and efficient Transaction Processing requires that a transaction be done
completely or not at all. When connected to a proper Database System, heitml
handles all transaction processing automatically and preserves the integrity of the
Database and Session Variables by saving them to disk. This means that a task can
be restarted at the point where an error occured, with full-confidence that nothing
was lost in the interim.
This page was dynamically generated by
heitml
© 1996-1997 H.E.I. All Rights Reserved
| 
heitml Takes the World Wide Web to a Higher Level!
