Timothy
Parker Consulting Incorporated
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| Questions and Answers, Part 25 Q:
We use Executive Software's Diskeeper utility to defrag our systems, but it
crashes under Windows XP. Is this a known problem? A:
Executive Software has released an updated version of Diskeeper, version 7.0,
that supports XP. Version 7.0 adds remote administration of the defrag utility
allowing a system administrator to initiate defrags on all machines on a network
when their load is minimized (such as at night). Q:
A customer asked if I can get a software package called JBuilder. I gather it's
a developer or programmer tool, but I can't find out more about it. Who makes it
and what is it for? A:
JBuilder is from Borland (www.borland.com) and it's a Java development
package. It's similar to Microsoft's J++ and several other Java Development
kits. JBuilder is a very nice package and can be ordered either directly from
Borland or through some of the warehouses that stock Borland products. Q:
Someone mentioned a protocol called CPIP.
I thought I knew a lot about TCP protocols, but I’ve never heard of
this one. What is it? A:
CPIP stands for Carrier Pigeon Internet Protocol.
It is a real protocol in the sense that the technology has been developed
and tested, but it isn’t likely to get either official approval from the TCP
gods or the end users any time soon. CPIP
was a fun project dreamed up by a group of Linux users in Norway.
They use live pigeons with small notes attached to their legs.
Each note is a scan of a datagram. The
pigeons fly from one node to another (mostly someone’s backyard) where the
datagram is scanned, and can then be sent electronically using traditional
means. Because most messages are
composed of many datagrams, there’s a lot of flying (and pigeons) involved.
Obviously, this was developed for the fun of the project, but it may work
in cases of a complete Internet crash! No
jokes from me about eating the messengers. Q:
A custom case builder I work with told me about a rule of thumb for cooling
a case and contents. Do you know
this rule? A:
It’s simpler than you think: if you can keep your thumb on the processor’s
heatsink after it’s been running for a while, the cooling in the system is
adequate. If you can’t keep your
thumb there, you need more cooling! Q:
OK, Linux guru. Is there such as
thing as a secure Linux version? Certified
secure, I mean. A:
Yup, there is. There are actually
two certified secure Linux versions I know of.
HP’s HP-LX is an expensive system but it is probably the most secure
Linux system currently on the market, and has passed many DoD security tests.
For those who want to spend less, NSA offers SELinux, although this is not as
heavily tested for security as HP-LX. Q:
What is a PAN? I heard it in a
conversation about PDA and cell phones. I’ve
never heard the acronym before. A:
A PAN is a Personal Area Network. The term has been floating around recently
with respect to wireless networks connecting your portable devices such as PDAs,
cell phones, laptops, MP3 or CD players, and so on.
The idea is that all these devices will communicate with each other using
a low-power wireless network that barely extends past your physical body, hence
the personal area network. There
are some problems with this idea, as the next question leads us into. Q:
I know Bluetooth is the standard for wireless networking, but it seems to me
there are other devices that share the same frequency band.
Doesn’t this cause interference with Bluetooth-compatible equipment? A:
Bluetooth is supposed to work over an 83MHz-wide band of the spectrum between
2.4 and 2.483GHz. This is not a
reserved area of the radio frequency spectrum, so Bluetooth devices are just one
of many devices that share that frequency.
Other devices that inhabit the same spread include cordless phones and
even some innocuous devices like your microwave oven. To prevent interference, in theory Bluetooth devices are
supposed to frequency hop 1600 times a second, changing exact frequency each
time. Bluetooth devices are not usually very powerful, usually in the 1 to 100
milliwatt range, so the Bluetooth devices seldom cause real problems for other
devices. Instead, the real problem
is other devices interfering with Bluetooth, which can happen often.
Frequency hopping is supposed to minimize that problem, but it still does
cause a hassle for early Bluetooth devices.
As more devices are introduced and Bluetooth becomes a more widely used
technology, you’ll probably see some improvements in signal integrity.
Chances of a reserved frequency for Bluetooth devices are almost
impossible. |
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