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#855: From the Archives: Doesn't Your Drive Need a Genius?, In From the Cold, It's All In The Genes

 
     
 

Hello all,

The cold persists, and at the time of writing this, the snow has pretty much all sublimated away, though we are expecting some precipitation today.

For now, everything is covered in the friendly, familiar sheen of road salt and mud and my kids look at me sadly as I drag them in their sled across the pavement from scrap of snow to scrap of snow. So goes January in Burlington.

Anyway, this week’s fare covers a new storage method and a couple of old friends, so I hope you enjoy and keep warm.

Thanks for reading.

Liam
liam@smalldog.com

 
   
     
  From the Archives: Doesn't Your Drive Need a Genius?  
   
 

Originally featured in Tech Tails issue #711.

One of the most popular questions I’m asked as a service technician is, “Should I have a utility to check up on my Mac?” The short answer is, yes, you probably should. While there are hundreds of utilities out there, I’m going to focus on the one I use the most, Drive Genius 2 by ProSoft. That’s not to say there are not alternatives that may be just as great, but Drive Genius has been a solid utility that I’ve used since it was first released.

Drive Genius is a nice solid tool because it incorporates utilities to check the hardware of the hard drive as well as the software. As with all utilities, it’s certainly possible to get false-negatives, but this could definitely help when trying to decide if the issue you’re experiencing is hard drive failure or software corruption. It gives you tools for surface scans, software verification and repair, integrity checks and even defragmentation (which is rarely necessary on a Mac).

Generally, if we get a machine in the shop and we suspect the hard drive is failing but it’s not as obvious as a drive that’s clicking repeatedly and won’t mount, we start running a surface scan on the drive. A surface scan checks for bad blocks. Some technicians believe that all drives have bad blocks; I respectfully disagree with that assertion. While it’s true that all drives may physically have some bad blocks, those blocks should be identified by software while formatting the drive and they are not used in the volume structure and should not show up in a surface scan.

To demonstrate that theory, if you run surface scans on 10 “healthy” formatted drives, there should be no bad blocks identified; that’s what we see in the shop. If bad blocks do show up that means something has gone wrong since formatting the drive and that is usually that the hard drive is physically failing. If you only end up with one or two bad blocks you can take the risk and reformat the drive and continue on with your day.

However, it’s recommended to check up on the drive from time to time because if more bad blocks show up, the drive should be replaced. If a surface scan is run and several bad blocks appear, don’t hesitate to replace the drive.

A drive displaying bad blocks is not the only type of hard drive failure. I’ve written before about a great tool by DriveSavers that demonstrates several ways a drive can fail. That means that a surface scan is not the end-all-be-all hard drive test.

If a drive that we suspect is failing passes a surface scan, the next step is usually to run an integrity check. The integrity check measures read/write speeds of the drive and compares it to a “normal” range. If the drive is performing drastically out of the normal range, it’s indicative that it’s time to replace the drive.

Aside from physical hard drive failure, often times drives that display symptoms of failure (like slowness and constant spinning beach balls) are actually a result of software corruption and not physical drive failure. While you can certainly verify and repair your hard drive’s volume structure by using Disk Utility, Drive Genius includes a “rebuild” function along with verify and repair.

Rebuild is particularly useful when the repair function is not up to snuff. I would say this is the #1 tool most home users would use. It is important to point out that not all rebuild utilities are made equal. While I love that Drive Genius includes that feature, and I use it regularly, Disk Warrior still wins in my book for its phenomenal ability to rebuild corrupt volumes.

The final feature you may wish to play with is defragmentation. Basically, when the drive head writes data to a hard disk it rarely puts things in the same physical place on the drive. Since data is constantly being erased and overridden there are pockets of space all over the drive so the drive head finds these pockets and splits the data up among them; this is called “fragmentation.” Over time, if files are badly fragmented it could take longer for the files to be retrieved so you might notice your machine is slowing down.

On a Mac, some defragmentation happens automatically as part of the boot up process, so most Mac users find they need to defrag much less often than PC users. Some Apple technicians say it’s not necessary to defrag at all, and I’m honestly close to that train of thought. However, I have found it’s helped in some situations; especially if it’s a large drive and has had very large chunks of data erased and re-written. I will say that I would not jump right to this step.

It’s also incredibly important to back up your data before defragmentation. While that should be an obvious step before running any major utility, I find it’s particularly imperative when defragmenting as I can vouch from personal experience that occasionally defragmentation can end up erasing or misplacing files and if those are system files you might end up with a machine that boots to a flashing question mark or to a kernel panic. That’s no fun!

If you don’t own a drive utility for your Mac, I encourage you to invest in one. While Drive Genius is my personal favorite, there are certainly others out there (including Onyx , a favorite of our readers) that you can try. Just do yourself a favor and be sure to back up your data first! Enjoy!

 
   
     
  In From the Cold  
   
 

It has been very cold here recently (sub zero) in the past week. Usually, we get several questions a week about whether or not one should leave a computer in the car when it’s so cold out. The bottom line is: don’t do it.

The operating range for Apple computers is 50-95 degrees (F). Most of us have used our machines outside this range, but what are the real dangers of leaving a machine in the cold?

The cold can drastically affect its functionality until it warms up, and in some cases, permanently damage your battery or shorten its lifespan. Really cold temperatures may even cause the machine not to start. The display could be affected until it warms up. The optical drive may not work until its internal lubrication melts. Of course, these are just minor irritations compared to the big issue.

Anyone who wears glasses knows what happens when you come in from the cold — condensation. The real danger isn’t condensation on circuit boards; plenty of electronic devices live in the cold with no ill effects. The real issue is the hard drive. Even the slightest amount of water on the platters can cause serious damage to the heads and thus, catastrophic data loss.

So even though none of us tends to wait long enough (just like we don’t wait before swimming after a meal), bring that computer in from the cold altogether, or at the very least, wait an hour or so before turning it on.

 
   
     
  It's All In The Genes  
   
 

Data storage in the digital age has changed the way we interact with the world. It is cheap, convenient, and fast. We snap thousands of pictures with no thought of developing costs. We can have terabytes of music and video stored (almost) literally in the palm of our hands. We rarely think about the possibility that all of our precious data can (and regularly does) go “POOF!” Digital storage is quick and easy, but is essentially simultaneously ephemeral and fragile.

As time goes on and the limits of storage capacity keep getting pushed, hard drives get more and more complex. The physics behind modern read-write heads and storage methods make today’s drives inherently more unstable than drives produced before about the turn of the century. This leads to more overall failures and more complex data recovery procedures when drives do fail.

This is a real issue that goes beyond the inconvenience of having to download all your iTunes again because your drive crashed. Long-term digital archiving is a field that companies are pouring money into, not only to save current data but also to preserve digital copies of paper records they may have destroyed thinking “Hey — we have it all on digital.” Simple is better for archiving; I have a box of snapshots going back many decades. Will my children be able to fire up my 2.5” external drive and look at their baby pictures in 30 years? It seems unlikely.

A European company has taken a new direction in data storage, and apparently they have made it work. EMBL-European Bioinformatics Institute (EMBL-EBI) has a working method to encode data on strings of DNA. Apparently they have encoded and decoded information already. DNA is a storage medium that has obviously stood the test of time — DNA “in the wild” seems to last a million years or so. That’s long enough for me.

Of course, the big issue will be making sure we have a machine to encode and decode the strings! I can’t help wondering what would happen if you could make proteins synthesize from strings of man-made data…like what would a movie or a song look like if you could have a machine make proteins out of the code? Or what would happen if you mixed “The Wizard of Oz” and “Apocalypse Now” together and tried to watch it? Martin Sheen hiding from flying monkeys in the rivers of Vietnam? The horror…

Anyway, here is the link to the article I saw on phys.org. Check it out!

 
   
     
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