Hard Disk Optimization Tools


Keeping a hard drive de-fragmented - often referred to as optimized - requires special software tools and is essential in maintaining peak computer performance. This article discusses some of those options for Mac OS? X. There is a technical distinction between Fragmentation (or de-fragmentation) and optimization. This article actually focuses on the fragmentation issue but the overall discussion and tools is still worth understanding even when dealing with optimization as it pertains to overall system performance.


Mac OS X Jaguar, Panther or Tiger and third part software applications.


Hard disk optimization requires using software tools to physically move data on the hard drive. This is a potentially dangerous task in that data can become damaged, lost or corrupted. The information provided in this article is provided as-is for general discussion purposes only. It is your responsibility to read, understand and follow all the warnings and recommendations provided by the software vendor of the Disk Optimization software you are using or hire a professional to perform the task for you. Performing a backup of your hard drive is always a good idea before performing major disk maintenance such as hard disk optimization / de-fragmentation.

Apple's Take on the Subject

Apple has a very interesting article on File Fragmentation and Optimization XTNL URL which is well worth reading. Among other items, it implies there are automated routines in Panther which may make disk optimization obsolete. One of the articles chief statements is de-fragmentation is potentially no longer required due to the significant increase in hard drive size. Frankly we're not convinced but have not had sufficient time to extensively test Apple's claim on the newest hardware. Based on personal daily use, we can say de-fragmenting a hard drive can help increase performance, particularly when drives are close to full (less free space).

Apple's other note pertains to Panther's internal use of Hot-File-Adaptive-Clustering (see above article link). An interesting concept which allows files 20 megabytes or smaller to be de-fragmented on the fly when opened. Take note of the 20MB limit. Files larger than 20MB may not take advantage of Hot-File-Adaptive-Clustering due to system performance issues nor does the process perform true optimization (streamline the postion of files on the drive for better performance). As such, a traditional de-fragmentation/optimization process as discussed in this article is still required. Mac Slash has an interesting discussion thread XTNL URL on this topic if you'd like to dig deeper.


Technical specifics on how files are stored on a hard drive are beyond the scope of this article. The related topic of File Directories is also not covered in detail here which can also have an impact on your system performance. Following is some basic information related to hard disk optimization and file storage:

  • every file stored (saved) on a hard drive has an address location (not unlike a house or apartment address in principle)
  • ideally every file is addressed to (saved to) a single location (that is, the file is saved in one, contiguous, location)
  • a file is considered fragmented when it is saved to more than one single location (that is, the file is broken into pieces where each piece has a unique address and it is not saved in a contiguous block often referred to as non-contiguous)
  • optimization or optimizing a hard disk is the act of moving all files which are saved in multiple locations on a hard drive (non-contiguous) into contiguous blocks (each file is in a single addressed location)

How does fragmentation happen?
Files can become fragmented through normal daily use of the computer as we add and delete (trash). It's important to remember when a file is put in the trash, and the trash is emptied, the file is not physically erased from the hard drive (unless specific steps are done to do so). Rather, the operating system flags the space the trashed file was saved to as being available to be saved over (much like we can re-record over a cassette tape). There is never a guarantee where the next, new, file is going to be saved to - an existing contiguous block or over an old file which may have been saved in multiple locations (fragmented).

Why is this important?
Every time a file becomes fragmented, each piece (or fragment) requires a address which is added to the file. If the file is saved in multiple locations it takes longer for the computer to locate the file because it has to look up multiple addresses instead of just one address. By de-fragmenting (optimizing) a hard drive, files are put back into single, contiguous, locations. Opening a file from a single location is faster and therefor helps improve system performance. A damaged or fragmented File Directory (the list of files on your hard drive) can also adversely affect system performance and repair and optimization of that data is a task separate from hard drive file optimization.

Hard Drive Optimization verses System Optimization in OS X
The Mac OS does not automatically perform hard drive file optimization (de-fragmentation) either after a software installation or update nor does it come with specific tools to perform the task we're describing here. Whenever an OS X System Update or software installation is performed, it's not uncommon to see a progress indicator in the installer noting Optimizing Installation or something similar. This is NOT the SAME as hard drive file optimization!

What to do

There are specialized software applications on the market designed to optimize (or de-fragment) files on your hard drive. Many of these applications also provide various other software tools which also provide tools for optimizing other aspects of your computers system performance including File Directories mentioned earlier.

General Approach for hard drive optimization
The following is a general recommendation for disk optimization. Developing a reasonable schedule for maintenance tasks builds good habits and helps keep the Mac OS in top condition. As such, the following general recommendation includes steps in addition to just optimizing the hard drive. How often these task should be performed will depend on your particular working conditions but the following is a reasonable start point:

  1. read, understand and follow all warnings and recommendations made by the software author for the application you're using to optimize, repair or maintain your hard drive
  2. backup your hard drive (integrating the backup into a routine disk maintenance cycle helps ensure it happens!)
  3. Repair Permissions: use Apple's Disk Utility (permissions are an integral component to the Unix, and therefore Mac OS X, operating system and can have a significant impact on performance and stability)
  4. use Mac Janitor or a similar utility to run CRON? maintenance tasks (visit this Knowledge base at Apple.com XTNL URL to learn more about these maintenance tasks)
  5. Check and Repair the Disk directories and general disk structure (Apple's Disk Utility can be used, command line fsck commands and third party applications such as Disk Warrior are all tools at your disposal)
  6. Optimize the hard drive: Tools such as Drive X or Tech Tool Pro 4 are available options
  7. restart and run Repair Permissions one last time for good measure

Those basic steps can help keep your computer running in top performance.

Following is list of some currently available tools:

Please note, updates are issued for third party applications and Apple's Disk Utility Application to make sure they are compatible with a particular version of Mac OS X. Always make sure you are using the correct application version of any program for your current operating sytem. Check the manufacturer's website for details.

Disk Warrior v3XTNL URL File Directory Repair and Directory Optimization - NO hard drive file optimization although there are rumors of one being considered for future releases. This is a rock solid product and we use it ourselves for personal and multiple computer installations (note, at the time of this article, we have had problems running Disk Warrior v3 with Panther. We think it's a great tool and highly recommend it for any version of Mac OS X )

Drive X XTNL URL System and Hard Drive Optimization (recommended for Jaguar only - we used this one too for pre Panther OS X systems. It's authored by the same folks who make Tech Tool Pro v4 which we now use instead of Drive X - still Drive X is well worth having if you're using Jaguar or older OS X operating systems)

Tech Tool Pro v4 XTNL URL System and Hard Drive Optimization. While the interface can be a bit intimidating, this is great all around tool and well worth having in the tool box! It has a wide range of tools including file and disk optimization, file recovery and allows you to perform a wide range of hardware tests.

Norton System Works XTNL URL We have mentioned this one for completeness only. After almost two decades we've found this utility creates more problems that it solves and do not let it near any of our personal or client computers. Additional searching in various discussion forums such as Mac Fixit XTNL URL will turn up others with similar opinions to ours and you'll find folks who love Norton and couldn't live without it. If we were running Windows / Intel PC's, then we'd seriously look at a Norton product. However, in our experience there are other, better, options for the Mac Operating System as we described earlier.

Updated: Norton has officially stated North System Works will not support the next release of Mac OS X (that is a release after the current Panther series). While we can't say we're upset by this fact, it should also impact on your decision if you're about to purchase disk utilities or need to plan for the future. Applications Like Tech Tools Pro and Disk Warrior have been around for more years than we can remember and are an excellent alternative to Norton System Works.

Mac Janitor, Cocktail & others: A very handy freeware utility for performing Mac OS X level CRON (house keeping) scripts. We use it and like it. There are other options to Mac Janitor including Cocktail and Macarroni which can all be found on www.versiontracker.com. Cocktail will perform a variety of other tasks including running repairing disk permissions and the like and can be a very handy tool to have around.

Apple's Disk Utility: Don't forget that great freebie that ships with your Mac! It's great for repairing disk permissions and general disk checks. Generally, if you're having problems running Apple's Disk Utility is the first place to start before trying more robust tools as noted above.

A good hard disk and system maintenance regime will go a long way to keeping your Mac in top operating condition.

We hope that helps

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