view in plain text or web browser  
Tech Tails | Apple news straight from the Tech Room | SmallDog.com | 800-511-MACS
 
#801: Resolving "Frozen" Software Update Downloads, Faster DNS Servers, A Logic Issue

 
     
 

Hello all,

Happy New Year to everyone! Irrational or not, I always feel refreshed and revived going into the new year. I find myself looking forward to the coming year’s challenges and opportunities and I can ride the feelings of goodwill and fellowship of the holidays for at least a month or so. (Somewhere around the end of February I get a bit over it…I haven’t done any winter sports for a few years and those activities used to keep me going.)

I plan to resist the genetic imperative many Vermonters seem to have—I will not be moving to Florida anytime soon. But I do find myself wishing for warm weather much earlier than I used to. I have a feeling though that I will become a fan of winter again once my kids can ride a ski lift. Some of the best times I have had have been on mountains in the winter, and I can’t wait to share the experience with them. In the meantime I’ll take warm feet and good books.

This week’s articles are a bit more on the technical side of things; practical info for experienced users and an intro to some more advanced ideas for beginners looking to try something new. Thanks for reading.

Liam
liam@smalldog.com

 
   
     
  Resolving "Frozen" Software Update Downloads  
   
 

When your Mac connects to Apple to update software, there are several steps it takes to complete the process. The software update system uses—at minimum—four different servers to check, verify and download the updates available to your machine.

The first server in the process and server that your machine connects to is swscan.apple.com. (These servers are not user-clickable links.) This runs a check to see what is on your machine currently. In the second step, it connects to swquery.apple.com to check to see what is available for the unit. The final two steps include two other servers, swdownload.apple.com and swcdn.apple.com, that verify the location of the downloads and the content that is downloaded. The actual downloads are served by Akami content distribution servers.

During the process of the download, your system may stall and not complete the download process. There are a few local files—caches of the download—on your machine that may be causing the issue. If the download stalls in the download process the content is saved in a folder, /var/folders/zz. Removing the contents of these folders may resolve the issues related to the hang in downloading.

To remove the downloads that have started, you need to open Terminal and navigate to the folder mentioned above, /var/folders/zz. After navigating to the folder in Terminal using the cd command, you can look at the content by typing the command ls. You will see several files in the folder all titled zzz something. To delete these files—which is safe to do—type sudo rm -rf * in Terminal. This directs the machine to, as a super user, remove the content of the directory /var/folders/zz. You’ll have to enter your password for the command to remove the files.

After removing the files you may now try to run Software Update again. Now that these caches have been removed, the system will start a new download of the updates and this may resolve the hang you have been experiencing.

 
   
     
  Tip of the Week: Faster DNS Servers  
   
 

Here in the Mad River Valley of Vermont, we are fortunate to have high-speed Internet access via the local utility, Waitsfield Telecom. Much of the system was just upgraded from 1.5 Mb/sec to 6 Mb/sec, some of us can upgrade to 12MB/sec, and some new constructions can even have fiber to their home or business.

Small Dog recently installed a new fiber connection, upgrading from a creaky old T1 that handled our web traffic and internal bandwidth needs. Despite my recent upgrade to 12 Mb/sec at home, it still takes a while for web pages to “resolve,” or begin to load, after entering the address and pressing return.

The Domain Name System (DNS) has many functions, one of which is to translate alphanumeric web addresses (www.smalldog.com) into Internet Protocol (IP) addresses. All internet-connected devices must have an IP address, and the IP address must be unique: no two devices on the Internet have the same IP address.

All Internet Service Providers (ISPs) maintain their own DNS servers, designed for use on their network, but in many cases these servers are not especially speedy. I decided to ask Google for fast free DNS servers, and I settled on two: 4.2.2.1 and 4.2.2.2. Web pages now seem to resolve much faster, making web browsing a more satisfying experience.

There is a better way, though. Namebench is an open-source utility from Google that seeks out the fastest DNS servers, and lets you graphically see just how much more speed you might get by switching to something faster. I gave it a try last night and did notice that pages seem to load a bit faster than before. Google also recently announced its own DNS server, and the terms and conditions say that browsing habits and history are not recorded. Give it a go!

Your DNS server settings can be changed in the Network Preference Pane under all versions of Mac OS X, or with AirPort Utility if you wish to change the DNS settings at the router level.

 
   
     
  A Logic Issue with a Logical Resolution  
   
 

A while back I spoke with a customer regarding a strange issue he was having while using Logic Pro on his MacBook Pro. I was able to successfully help him based on the insight I had gained from having a similar issue myself.

The issue was related to an error message popping up while in the middle of recording one or many tracks, that reads: “System Overload” or “Disk is too slow”, followed by an error code. In addition to the error message, the track or tracks you were in the middle of recording would abruptly stop recording, halting any progress you had made. An extremely frustrating issue indeed, I needed to get to the bottom of this.

I had been using Logic Pro on my MacBook Pro for years without any issues. I use a multi-channel FireWire interface, and sometimes record up to 8 tracks at a time, flawlessly. I was baffled at how often this issue was happening now, considering I had never seen it before. My laptop had always been able to handle this load, no problem. Was there something wrong with my computer’s hardware? I hadn’t experienced any issues or abnormalities in anything outside of Logic, so my assumption was some configuration issue or glitch with Logic.

I researched some reliable forums, with no luck. I decided to start leaving the System Performance window open while recording, closely monitoring it. This window is very similar to the utility Activity Monitor, as it monitors your CPU/Ram usage on one meter, and disk bandwidth used on the other. I started noticing that right before the overload error occurred, I would have a massive spike in disk bandwidth. The only different variable from before, when I could record with no issues, was the environment in which I was recording. A small practice space in which I was right next to the source. This particular day we had decided to record bass. Loud, rumbling bass. My MacBook Pro was stationed about five or six feet from the hulking bass amp, on a hardwood, not very structurally sound, table.

At the time, I was not an Apple technician, however I was aware of the Sudden Motion Sensor built into my laptop, and how it worked. I grabbed the neoprene/foam sleeve I used, and placed it under my laptop (being careful not to obstruct the intake/outtake vents!), and attempted to record a dummy track, no errors. I tried a few more, just to confirm. The errors were gone! The vibrations coming from this bass amp had been just enough to kick the Sudden Motion Sensor on and park the hard drive heads, halting any hard drive activity, and causing an interruption in the recording.

Apple has since updated the error message, with the implementation on Logic 9.1.4, and issued a Support article, which can be found here: http://support.apple.com/kb/TS3834?locale=en_US

To learn more about the Sudden Motion Sensor in your laptop, Apple has a Support article here: http://support.apple.com/kb/HT1935?locale=en_US

 
   
     
  TT SPECIALS | 1/10/12 - 1/17/12  
   
   
   Save $25: Apple Time Capsule 2TB Dualband
274.99
View  
   Free shipping on ProSoft Engineering Data Rescue 3 - Unlimited Use
99.99
View  
   Free shipping on Matt's favorite keyboard: Matias Tactile Pro USB Keyboard
139.99
View  
   $20 Mail-In Rebate + free shipping on Microsoft Office Home/Student
119.99
View  
   Save $10: LoJack for Mac notebooks - Standard 3-Year Subscription
69.99
View  
   CyberPower 550VA 330W UPS
54.99
View