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#900: How iOS Touch Screens Work, To Clone Or To Backup, Disable Window Animations in Terminal


Greetings Again!

I hope you enjoy another week of Tech Tails and learn a little something. We have some very interesting articles for you this week. I am one of the technicians in the Manchester, NH store, and one thing I always seem to notice is how little people backup their data. Unfortunately, since most people have SATA hard drives rather than solid state drives, many will experience hard drive failure at some point in their computer lives.

There are the obvious ways, such as a clicking sound, but there are other signs as well. Frequent freezing and/or a flashing folder-slash-“blue screen of death” (for Windows users) are some. If you begin to find files that fail to open and are corrupted even though you may have saved them without errors, they could be indicating another form of hard drive failure.

Of course, various other symptoms can seemingly be unrelated to hard drive failure at first, so you should automatically be making a backup of your data (just in case).

We’re here to help diagnose the problem if you see or hear any of these signs. If you are not currently backing up your data, we have solutions and ways to teach you and get you up and running. With so much based on computer processes, it’s never been a more important time.

Have a great week everyone!


  How iOS Touch Screens Work  

Back in the day, I owned a Palm Pilot and recall the touch screen behaving far differently than iOS devices in that pressure was required (and felt) to signal the processor. This type of digitizer is called a “resistive screen,” and takes advantage of finger or stylus pressure causing two thin layers to come into contact at a precise point, thus changing the resistance and signaling an instruction to the processor. These screens were predominant back when Palm Pilots were all the rage — I can assure you they no longer are.

We know that iPhones and iPod Touches are the rage though and they use what are called “capacitive touch screens,” relying on the conductivity of your skin to affect changes via signal path. The display houses an LCD, a glass substrate containing a very thin conductive layers, another glass substrate containing another very thin conductive layer, a transparent “bonding” layer, and finally the glass cover that you actually touch. On later models there is yet still another fine anti-reflective, oleophobic — from the Latin “oleum” (oil) and Greek “phobos” (fear) — layer.

So if you were to get up close and personal with the screen — using a microscope of course — you would see a grid array in the glass substrates: the bottom layer houses very thin, vertical, metal strips called sensing lines that detect electrical current at intersections (“nodes”) with the horizontal lines of the top layer, called driving lines. The driving lines carry current whenever the screen is on so that any interaction with the fingertip or stylus can be registered. This symbiotic relationship of the two layers is called mutual capacitance.

Because living creatures have capacitance (we can store / conduct electricity), when you touch the screen, you are lowering the amount of charge at specific junctures as a small amount of the charge from the driving lines (why its substrate is closer to you than the sensing lines), transfers to your finger. Electrical impulses are sent to the processor for further analysis once the raw data of your touch is collected based off of its coordinates on the grid and its affect on the circuitry.

The processor uses several important pieces of software, built into the device’s memory, to analyze your electrical impulses. It needs to know the size, shape, and duration of your touch; movement (for gestures), placement, context (what application are you trying to use), and it needs to know whether there are one or multiple simultaneous touches. Apple has engineered the software to recognize a relatively limited set of possibilities so that if the software receives raw data that is unknown, it will not acknowledge the signal as a touch.

As with all modern day computations, the aforementioned sequence of events happens in nanoseconds, giving you the impression that you’re executing commands in real time with your finger. If you feel like your screen is not responding the way it should across all applications, there is likely an electrical fault that requires a replacement.

These incidents, however, seem few and far between due to technological advancement (manufacturing techniques) and that the LCD/digitizer/glass is all crammed into one thin component. You may notice that cracked glass rarely renders the digitizer useless because you’ve only damaged one of the several layers comprising the display. You should seek to get it fixed regardless so that there is no breach in the system and so you don’t hurt yourself!

  To Clone Or To Backup  

The benefits to cloning software versus back up software is something measured in time. How technologically savvy you are tends to guide you toward one or the other. Currently, my workstation here at Small Dog in South Burlington has a failing hard drive. Since everything is backed up to our remote management server, I’m not worried about data loss, but my concern at this point is the amount of time my workstation will be down and how productive I can be once it’s up and running again.

As I type this article, my workstation’s hard drive is currently being cloned to another hard drive that will replace the failing one. Cloning allows for the entire drive contents, OS and all to be copied over to a new drive, allowing you to pick up where you left off as if nothing has changed. There is an amount of setup and reorganization with backups and restoring from them. Both are a good thing to do, but cloning is only really a benefit if you are going to be doing the hard drive installation yourself.

I always recommend some form of backup regimen, but if you are experienced and know how to replace hard drives, then cloning software might be better then say, Time Machine. Or, you could use both — have cloning software constantly keep one hard drive backed up while using time machine for a redundant backup. That way, if one drive fails, taking your clone with it because of software corruption, you still have all your files backed up with Time Machine.

Of course, there is a possibility that the clone might become corrupt while cloning from a failing drive. I’m watching my drive getting cloned and there are error messages about sections being difficult to transfer. I will probably have to install a fresh copy of the OS over the top of what I have, effectively replacing the OS and leaving all my work data there. Then, I will have to reconfigure a lot of settings to be able to interface with work systems. If this happens, I may be down longer than I originally anticipated, and may need to restore the system the long way.

The manipulation of data is a crap shoot at times, especially whenever the medium that its placed on is in the process of failing. There isn’t really any guarantee that everything or even anything will be recovered, but if you catch your drive failure at an early stage, the better your chances are of being able to recover everything. (For previous articles on data recovery, check out the Tech Tails Archives.)

I’m currently using Mac-based software Carbon Copy Cloner. There are numerous Windows-based programs that do similar services, and Acronis is one that I can recall off the top of my head. Once the cloning process was complete, I installed the new drive into my workstation and booted it up.

Other than a few programs which I will have to reinstall, it appears to be working as if nothing happened, which allows me to get back to work in a timely manner. I can’t stress enough — back up your data because if you lose it, it may be gone forever.*

*Or super expensive to recover using DriveSavers or other data recovery service!

  Disable Window Animations in Terminal  

If you have an older Mac and have updated it to more current software and feel that the machine is just not responding as quickly as it used to, this could be a useful trick for you.

The newer operating systems utilize a lot of animation features that are very slick with a machine powerful enough to show them well, but if you are on an older machine, they can cause sluggishness that is just unnecessary. If you want to disable them, here is a command for Terminal that will allow you to do just that.

Before playing with Terminal it is always a good idea to make sure that you are comfortable with it as entering something incorrectly could be catastrophic for your machine.

defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool false

What that does is disables all window animations in OS X, allowing the processor to focus on what you’re trying to do. To disable it is enter the following:

defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool true

This will bring back the functionality that was disabled by the previous command.

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