Timothy
Parker Consulting Incorporated
|
|
|
|
Questions and Answers, Part 10 Q: I attended a network security
seminar and the presenter mentioned DDOS (not just DOS: Denial of Service).
When pressed for details, he hemmed and hawed and skipped on to another
subject. What is DDOS? A: DDOS is Distributed Denial of
Service and uses a network of computers to issue Denial of Service attacks.
At the current time, it’s estimated there are about 4,000 DDOS attacks
a week in the US. DDOS has been
helped by some unintended code in Windows 2000 and Windows XP (Microsoft has
issued fixes for the Windows 2000 problem and will fix XP in the next Beta
release). Before we dump on Microsoft, DDOS has been possible for years through
UNIX and Linux systems, using a technique called IP spoofing.
There is software that can prevent DDOS attacks on your servers and
firewalls, and it is slowly becoming a major issue in the firewall business.
Unfortunately, the hackers are way ahead of the security folks on this
issue, and there are tons of tools available for hackers and wannabe hackers to
start DDOS attacks. Expect the
attacks to get nastier before things get better. Q: Settle a bet for us.
What’s the fastest computer in the world right now? A: I have to answer with two
different names, because it depends on your definitions.
The generally-accepted answer of the fastest general-purpose
supercomputer is the IBM ASCI White. The
ASCI White has been measured at 12.3Teraflops (trillion floating operations per
second). The second answer is that
the absolute fastest supercomputer currently available is the GRAPE-6,
originally developed at the University of Tokyo for astrophysical calculations.
The GRAPE series of computers are designed for specific types of
calculations only, but are blindingly fast at these. The basic GRAPE computer is
only $13,000 US with four GRAPE-6 CPUs on the motherboard.
A 1 Teraflop GRAPE-6 system costs $42,000 and has 32 CPUs. Since a GRAPE
system can have up to 32 of these boards, there’s a theoretical speed of
32Teraflops available. The
researchers are still pushing the GRAPE-6 system to record speeds, and the
GRAPE-7 is on the drawing boards. Q: What’s the difference
between GNOME and KDE for Linux? A: GNOME (GNU Network Object
Model Environment) and KDE (K Desktop Environment) are two different front end
GUIs for Linux. Both run on the
same Linux platforms, but there are two different sets of rules for writing for
the different GUIs. Right now, the
two are not interchangeable, and applications written for one may not work under
another. The two look a little
different, but both try to provide the same basic look and feel for Linux users,
much like Windows does for DOS platforms. The development of the two different GUIs has caused a bit of
a rift in the Linux world, with almost equal acceptance of both.
The good news for the future is that both environments are working
towards interoperability in future releases, where applications can run under
either and the two will look similar to users. Q: I heard a vendor talk about
iSCSI. Is this yet another SCSI
versions? A: Nope.
iSCSI is short for IP over SCSI. As
the name suggests, it’s a way of sending TCP/IP packets over a SCSI cable.
The idea is to allow large storage pools on a network to be joined
together by fast SCSI cables (probably fibre) and use IP to allow access to the
pools. This will result in easier access for workstations and
servers, and allow multiple storage pools to work together faster over the SCSI
cables. One of the touted
advantages of iSCSI is that there are many more IP-knowledgeable people who
could work with this protocol than there are people who know Fibre Channel.
Regardless, there are only a few iSCSI devices on the market now, and they tend
to be expensive, but this may be an interesting storage development for the near
future. Q: I just got used to DLT tapes.
Now I hear there’s a Super DLT. What
is it and who makes it? A: DLT (Digital Linear Tape) is a backup medium that allows in the neighbourhood of 70GB compressed data (about 35GB native) on a single DLT cartridge. For higher capacity applications, Quantum (who really started the DLT thing in the first place) has announced Super DLTtape, which will allow 220GB on a cartridge with a transfer rate of 22MB/sec. Drives and media are starting to appear, but they are expensive! |
|
Send mail to
tparker@tpci.com with
questions or comments about this web site.
|