Wilcox, Campus Web Administrator
Beware the Wireless
spoke at the SIGS/101 Communications JavaPlus conference
in San Jose, CA. One of the most interesting discussions
I sat in on was about the future of Java and wireless
devices. There is a significant revolution going on with
wireless overseas, primarily because standard telephone
access (and thus Internet access) is more expensive and
in many cases, less reliable than it is in the US.
The reason wireless was brought up at a Java
conference was because there is a version of Java that
has been modified for these 'micro-devices' which include
Cell-phones, palm-type computers and devices that fit
somewhere in the middle of these two. This version of
Java called J2ME (Java 2 Micro-Edition) is a reduced
sub-set of the standard Java environment designed for the
limited amount of memory and disk space these systems
Some interesting observations came out of this
- Moore's law on computing (computer power doubles
every 18 months) applies even to micro-devices.
The newest cell-phones are shipping with 8 MB of
RAM and 40 MHZ CPUs. Yes these are tiny compared
to your PC with 800 MHZ CPUs and a gigabyte or
more of RAM, but these devices are the equivalent
to the most powerful desktops in 1990. Some of
these manufactures are now shipping with the full
standard Java desktop edition on a cell-phone!
- As computers have grown more powerful and
functional, the available bandwidth grows more
limited. You think 28.8 modems are slow, try a
- We need to rethink transactions. Transactions are
the process we use to maintain data integrity in
a multi-step computational process. What
transactions allow programmers to do is to treat
a series of steps (for example withdrawing money
out of your bank account) as a single operation.
If any of the steps fails (you lose power during
the withdrawal), the system reverts back to the
way it was before any of the steps were
completed. In typical client-server applications,
losing a connection and causing a rollback are
fairly rare because of the quality of the
network. In a wireless environment, we might lose
the connection at any moment (you go out of
range, drive into a tunnel, lose battery power
etc.) or the connection could easily be garbled.
We now must build our applications to learn to
handle these situations. Quite a challenge!
Until next time.