Feature

Drive dysfunction? The disc doctor can help

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Efficient PC usage depends on maximising the capabilities of the hard disc. Third-party software may offer advantages over what is available on your operating system

Disc utilities belong to an all but forgotten branch of the computer industry. Not so many years ago these useful programs were essential tools in the IT department’s box of tricks and there were plenty of products to choose from. Today, it is hard for most people to stretch beyond the Symantec range of products, primarily Norton Utilities or Partition Magic, and many jobs that used to be routine are now left undone.

It is only 25 years since the PC was created by IBM, and its operating system roots were firmly planted in the CP/M system developed by Digital Research.

The IBM PC assisted Microsoft’s rise to fame because IBM needed an operating system for its new device. Digital Research was not available, but Microsoft’s founders, Bill Gates and Paul Allen recognised the golden opportunity that IBM was offering.

Buying in a product called QDos (reputedly an acronym for “quick and dirty operating system”), Microsoft created MS-Dos (Microsoft Disk Operating System) and the foundations of an empire were laid.

In effect, MS-Dos was to CP/M what Linux is to Unix today. It offered a new way of solving the same problem, but initially offered a refinement of what went before rather than a radical new look at what the operating system could be.

MS-Dos was an unfriendly environment and needed management. One of the operating system’s glaring omissions was that it offered users no way to recover files that had been accidentally deleted.

Peter Norton saw an opportunity and created a simple undelete function, packaged it and gained a fair degree of success. The product, Norton Utilities, has been upgraded and enhanced many times over the years, and currently contains more than 50 useful tools for recovering and managing Windows data at a low level. A well-designed interface allows relatively non-technical users to deploy Norton Utilities’ functions with ease.

The undelete function has been a cornerstone of Norton Utilities. Symantec acquired Norton in 1990, and other companies such as Mace and Central Point Software likewise rose and fell victim to acquisitive competitors such as Symantec and Network Associates/McAfee.

Microsoft has also flirted with the utilities market and there are still some useful, but not well-publicised, features buried in Windows. Windows’ main built-in utilities are its defragmentation and disc partitioning functions.

Defragmenting is the process of tidying up data storage on a single disc. As a disc fills up, the operating system stores data wherever it can find enough space. Although this is good for making the maximum storage space available, it can affect system performance and slow the disc-drive down.

The problem is that larger files are broken down into blocks of data, which are stored and indexed all over the disc. When a file is read back into the computer, its constituent blocks have to be reassembled in memory.

When a disc is new (and therefore largely empty), file blocks are stored in a methodical and highly efficient way, but as time passes and the disc fills with data, so free space becomes harder to find and the system stores blocks of a file anywhere that space allows, with the result that files become increasingly fragmented over time. This forces the drive to spend more and more time hunting blocks down when it needs them, and large files accordingly take longer to load.

Defragmentation, or defragging, is a housekeeping process that tidies up the disc and moves the data blocks of a file closer together so that the disc drive can work at maximum speed.

Clive Longbottom, service director for business process analysis at Quocirca, remains unconvinced by Microsoft’s defragmentation programme.

Microsoft’s defragmenter is based on software from Diskeeper, formerly known as Executive Software, but lacks the ability to zone commonly used application code on the disc, which would make access even faster. However, the real problem is that while Diskeeper’s branded software and Symantec’s defragmenter work in the background, the native Windows utility makes the system unavailable during a defragmentation process that can take several hours.

The current argument is not so much about which disc organiser is best, but whether they are necessary at all. In the past when storage was at a premium, defragmentation could offer beneficial speed improvements in the 50%-80% range, but times have changed and Diskeeper rates the average speed improvement from defragmenting as ranging between 10% and 20%.

“For users with, say, a 350Gbyte disc with less than 100Gbytes of data on it, fragmentation will be low,” said Longbottom. “It will only become a big problem when the disc reaches about 65%-75% full. These days, fragmentation is far less of a problem than when we were struggling with 50Mbyte discs.”

The improvements in reliability and pre-emptive disc caching have negated some of the problems relating to fragmentation, but significant improvements can still be gained where data streaming of large files is common.

If defragmentation is chosen, the benefits of background defragmentation are outweighed by the overhead this places on individual PCs. Longbottom is an advocate of the practice of keeping the defragmenter in the systems administrator’s domain.

“Tools for speeding up machines should not be left in the hands of users,” he said. “The technical staff should control this, and companies should be utilising centralised management tools to carry out these tasks overnight or at other low-usage times.”

The partitioning utility that Microsoft bundles with Windows is even more basic than its defragmenter.

The option seems to have been included as a one-off method to separate a single disc into several virtual discs. The basic features provided are aimed at conditioning discs on new PCs or preparing a new disc added to an existing computer. Once a disc has been split into virtual drive partitions it is impossible to change anything at a later date without destroying some or all of the data.

This is where commercial products come in useful. Symantec’s Partition Magic is one of the best known, but there are several alternatives, including Acronis Disk Director Suite, VCOM Partition Commander, Paragon Partition Manager, and the freeware utility Visopsys. Most of these packages run under Windows, but they can also create Linux partitions as well as all Microsoft storage formats from Dos to NTFS.

Partitioning is particularly useful for current large hard discs, to separate the operating system, applications and data into separate areas. This can prevent all data being corrupted should a malfunction occur, and protect against certain virus attacks. The separation of data from applications and the operating system can also make backups easier to configure.

These disc utilities are aimed at consumers and small businesses because most larger enterprises partition a reference configuration and then distribute that as an image.

When it comes to creating an image, Symantec Ghost is the clear leader, but there is a cheaper option in G4U (Ghost for Unix). Although G4U may sound unsuitable for Windows, it boots the workstation from a floppy disc and the image produced can then be distributed using any chosen Windows system.

Undelete may have been the software that kicked off the whole utilities market, but it still has a role today. The software’s job is made relatively easy by the fact that a computer does not actually obliterate a file when a user presses the delete key. Instead, it merely replaces the first character of the filename with a particular letter that the system uses to denote a deleted file. Simply by changing this character back to the original character, the undelete utility can revive the file.

There is one important caveat with undelete and that is that the deletion process makes any space used by the file available for re-use by other files. If this has happened, then the file will be gone forever, overwritten by other data in a subsequent operation.

Worse can happen if the disc’s own filing system is damaged. The filing system is where the disc keeps a map of itself, including where partitions start and finish and what files are present. These may be damaged by viral activity, accidental formatting or disc corruption.

Businesses have thrived in the data recovery area but many, such as Vogon International, are concerned with physically damaged discs. Sometimes a drive can be recovered by software utilities. Even reformatted discs can be recovered unless they have been securely erased.

Chengdu Yiwo Tech Development Company has a range of products under the Easeus range. The suite comprises Data Recovery Service, Data Recovery Software, Partition Recovery Service, Partition Recovery Software, Data Security Software and File Repair Service. 

Other packages include the small but effective Active@ series of utilities. Active@ Undelete is not a file undelete program, but a data recovery suite that helps to recover lost, deleted and formatted data on local and network drives, as well as removable drives and digital media cards. It also supports EFS (encrypting file system) file recovery and damaged Raid (redundant array of independent discs) reconstruction, and can create a disc image to protect data from future mishaps.

Longbottom feels that the advent of Windows Vista next year will change the utility software market substantially.

“Overall, I see the utility suite market cooling down, unless the suppliers involved can come up with new stuff under Vista that does far more than Microsoft will do,” he said.

“This will probably be less techie and more user-focused. I would guess at it being a mix of personalisation tools and multimedia optimisation tools, but still backed up with a full anti-malware tool for virus, spyware, adware removal and so on.”

Disaster and defrag under Linux

There are many Linux utilities available of varying quality. The best way to find the most acceptable is to see what is recommended by Red Hat, SuSE, IBM and other major supporters. Most of the packages are free to download so you can test out several to see which most suits your purposes.

Linux file systems resist disc fragmentation. A typical Linux disc partition would typically be between 2% and 5%  fragmented and rarely exceed 20% fragmentation.

For this reason the Ex2defrag program is rarely used, especially as the partition has to be unmounted, and therefore becomes unusable during processing.

Many systems administrators would regard as unacceptable having to put a partition out of service for the duration of a defragmentation.

There is also an argument that defragmenting files actually degrades performance and disc space availability by undoing the benefits of the sparse file storage that is employed by Linux.

Linux also has an inbuilt method for recovering deleted files. It is not a simple process and there are free utilities, such as the Linux Files Undelete Utility and GtkRecover to help, but even then the process is more complicated than in Windows, especially if the file is large.

When Linux loads up, it offers the chance to partition the disc. If the partitioning needs to be done later, many of the Windows partitioning applications can be used by booting up from the CD or from a floppy disc.

Disaster recovery is a little easier on Linux than on Windows. Knoppix, for example, offers a disc-bootable version of Debian Linux with the K Desktop Environment graphical user interface on CD or DVD. The disc also holds several utilities to help correct errors on the failed disc to clean it up and make it bootable again.


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This was first published in May 2006

 

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