What are Aplets and e-Lessons?
Everything on an HP38/39/40G calculator revolves around the use of aplets.
Like any other object on the calculator, an aplet can be saved to or retrieved
from the PC using HPGComm.
In
addition to this you can also download special aplets from the web (see the Help
page for suggestions) to enlarge the capabilities of the calculator or which can
be used in teaching. When the HP39/40G was released in 2000 Hewlett
Packard decided to change the name of this type of aplet to
"e-Lessons" in order to emphasise their usefulness in teaching. There
is no actual difference.
The
images that are shown here are taken from a number of teaching aplets which are
available from this web site. Including those from HPs website there are
over 100 aplets of this type available.
These aplets achieve their enhanced abilities through 'helper' programs associated with the aplet and which download (or upload) automatically with the aplet. The aplet is controlled using the VIEWS key on the calculator, with the programmer having 'hijacked' the normal VIEWS menu and substituted a new menu.
It is critical that the transfer not be interrupted during the transfer of these helper programs. Not only will the aplet not work correctly without them, there is a known (and not fixable) bug in Windows 95 & 98 that can cause difficulties for HPGComm when a transfer is interrupted.
These
helper programs are usually named after the aplet. For example an
aplet called "Linear Programming" might have helper programs called .LINPROG.ANL,
.LINPROG.PLT, .LINPROG.CON etc.
Once you have transferred these aplets to your calculator then you must be careful not to delete the helper programs from your Program Catalog unless you have finished using the aplet.
On the other hand you need to be aware that deleting the aplet from the Aplet Library view will not automatically delete the helper programs. You must change to the Program Catalog and specifically delete them after you have deleted the aplet in the Aplet Library. This can be a bit of a pain but if you don't do it then the Program Catalog will eventually fill up with them to the point where you can't find the programs you want.