The key asset of Internet is the domain name directory known as DNS. A root name server is a DNS server that answers requests for the root namespace domain, and redirects requests for a particular top-level domain to that TLD’s name servers.
There are currently thirteen root name servers around the world. Most of the servers reside in the United States while the rest exist in multiple locations on different continents. The US government plays a key role in supervising the asset.
In the early hours of Tuesday, three key servers were hit by a barrage of data in what is known as a distributed denial-of-service attack (DDoS). There is no evidence of damage proving once again the robustness of the Internet.
The servers under attacks are as follow:
- G-root, G.root-servers.org at Columbus, Ohio, USA
- L-root, L.root-servers.org at Los Angeles, California, USA
- UltraDNS, authoritative for .org and .info TLDs
Ignition Interlock Device: A Concise Overview
0 Comments Published November 22nd, 2006 in Infrastructure.
Mothers Against Drunk Driving (MADD) and the U.S. Department of Transportation with the backing of car manufacturers such as Volvo and SAAB is set to launch a new campaign against drunk driving by mandating a Ignition Interlock Device on every car.
The device is effective to repeated offenders but expensive to nondrinker. Since July 2004, more than 75,000 Ignition Interlock Devices (IIDs) were installed in the U.S. because of DUI and DWI convictions.
What exactly does the device offer? Let’s take Guardian Interlock Systems as an example. The company has been in the business since 1985 and the first to introduce the device in California.
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Large sequential I/O can cause performance problems due to excessive use of the memory page cache. One way to avoid this problem is to use direct I/O on filesystems where large sequential I/Os are common. Direct I/O is a mechanism for bypassing the memory page cache alltogether.
DIRECTIO_ON allows you to force directio per-file and is used by Oracle database. The idea is that with a properly sized memory area the database can manage its own buffering and avoid the overhead of copying to kernel buffers. Even after the database is shut down directio will persist for a long time. The flag is set in the inode’s i_flag and hangs around cached within the inode in the DNLC and will effect files until the inode is flushed from the DNLC.
John Alderson demonstrated the problem using two simple C programs.