Archive for April, 2010

Windows TCP max limit for concurrent TCP socket connections

30 Apr 2010 at 09:08

Terry Moore

Networking, Technical, Windows

No Comment

While trying to diagnose a network/application  issues with my companies application and the client’s network we got on the topic of possible running out of out TCP sockets on either the client workstation or the server.  While I didnt have any concrete facts as to whether this was a possible issue I turned to my trusty friend, google.com.  Very quickly I can across an article the goes into great detail about this exact topic and I felt that it was to good to not let everyone else know about it also.

To keep the TCP/IP stack from taking all resources on the computer, there are different parameters that control how many connections it can handle. If running applications that are constantly opening and closing connections (P2P), or are providing a service which many tries to connect to at the same time (Web-server like IIS), then one can improve the performance of these applications by changing the restriction limits.

The author also goes in to great detail about how to configure Windows networking for maximum performance.

This is definitely worth the 10 minutes to read.

Arch Linux developer passes away

29 Apr 2010 at 15:01

Terry Moore

Arch, Linux

No Comment

Jan Mette, aka fuckyou, passed away last Friday of unknown causes.  Jan was the creator of the widely used KDEmod and Charkra project, a well regarded developer of the Arch Linux distribution and was prominent figure in the Arch Linux community.

Hello Phil,
my name is Daniela, the girlfriend from Jan and have to inform you that Jan
died this morning sleeping at home. Yesterday he was still fine and there
were no signs for that. Also the police will check whats happen to him. If
there should be an interest I’ll inform you all from Chakra about the
inhumation in his home town Luedenscheid middle/end next week.
Regards,
Daniela

Post condolences here

The Linux Boot Process

26 Apr 2010 at 13:14

Terry Moore

Linux, Technical

No Comment

When a system is first booted, or is reset, the processor executes code at a well-known location. In a personal computer (PC), this location is in the basic input/output system (BIOS), which is stored in flash memory on the motherboard. The central processing unit (CPU) in an embedded system invokes the reset vector to start a program at a known address in flash/ROM. In either case, the result is the same. Because PCs offer so much flexibility, the BIOS must determine which devices are candidates for boot. We’ll look at this in more detail later.

When a boot device is found, the first-stage boot loader is loaded into RAM and executed. This boot loader is less than 512 bytes in length (a single sector), and its job is to load the second-stage boot loader.

When the second-stage boot loader is in RAM and executing, a splash screen is commonly displayed, and Linux and an optional initial RAM disk (temporary root file system) are loaded into memory. When the images are loaded, the second-stage boot loader passes control to the kernel image and the kernel is decompressed and initialized. At this stage, the second-stage boot loader checks the system hardware, enumerates the attached hardware devices, mounts the root device, and then loads the necessary kernel modules. When complete, the first user-space program (init) starts, and high-level system initialization is performed.

That is a quick overview of the Linux boot process.  Dive in to greater detail here.

The Great Server Room Flood of 2010

24 Apr 2010 at 21:25

Terry Moore

Technical

No Comment

OK that title is a little dramatic but it could have been bad.  Here is what happened.  I had to go in to work this morning to upgrade a customer’s servers remotely and managed to leave my phone at work.  After I took my kid to swim lessons I went back in to work to get my phone.  I decided to show my kid the server room, which turned out to be a good idea, because when I opened the door I saw, to my surprise, a puddle of water on the floor.  I looked up and saw a ceiling title that was completely saturated with water.  I ran around the office grabbing as many trash cans as possible because I didn’t l know what would happen once I knocked the ceiling tile out of the ceiling.  Luckily the water that was dripping down from the ceiling was about 6 inches from a server rack and not on top of it.

After knocking down the tile, which basically crumbled when I touched it, I was able confirmed the source of the water.  Over the servers is the air conditioner.  Below the the air conditioner is a drip pan that is about 5 ft long 2.5 ft wide and about 2 inches thick.  I grabbed a step stool and stuck my hand in this drip pan.  It was completely filled with water.

I knew that I had to drain this water but I was unsure exactly how.  So I ran over to the tool box and grabbed the drill and a the biggest bit I could find.  I knew that if I waited much longer that drip pan was going to start to over flow in more areas then just the one corner that wasn’t over the servers.  Once again I ran around the office this time I grabbed the 14 gallon tubs that we use as paper recycle bins.  I get on the step ladder and start drilling the hole.  As excepted, the water started to rush out.

Forty-five minutes later the drip pan is finally empty and one 14 gallon tub is full.  I found that the water is coming from the air conditioner’s relief pipe. What I don’t know is why it is dripping as much water as it is. I guess I will find out Monday morning when the HVAC people.

Here are the pictures that I took with my iPhone.  Sorry the the quality is kinda bad but I was in a hurry to get the water cleaned up.

Update (2010/04/27):
The fine HVAC folks at Newcomb came out and determined that the issues was a clogged drip pipe.

Digital Photocopiers Loaded With Secrets

22 Apr 2010 at 21:34

Terry Moore

Technical

No Comment

Nearly every digital copier built since 2002 contains a hard drive – like the one on your personal computer – storing an image of every document copied, scanned, or emailed by the machine

Scary!  More.

Apple, Gizmodo, the “misplaced” iPhone 4G and the law

22 Apr 2010 at 21:12

Terry Moore

Apple, iPhone

No Comment

John Gruber over at DaringFireball.net has a excellent article talking about the possible legal troubles that either the person who “found” and sold the prototype iPhone 4G and for Gizmodo, who purchased the iPhone.  From what it sounds its now in the hands of either the California District Attorney to pursue criminal charges or for Apple to pursue the case in a civil court.  I guess only time will tell.

Update:
For every point there is a count-point and Giles Bowkett believes John Gruber is a little naive about the law and also a little bias toward Gizmodo being in the wrong.

In any case its always good to hear more than one point of view.  Also as far as I am concerned I am taking these posts as just opinions because I don’t know either person from a hole in the ground.

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