Half Inch Open Reel Tapes

In 1951 the first magnetic tape media for storing computer data was introduced, using the half inch tape media, used in the UNISERVO tape drive used on the UNIVAC I computer. IBM introduced the 7 track recording format the following year with half inch media wound onto open reel spools, which used the linear recording format.

Half inch open reel media was the standard backup and near line storage medium of choice within the enterprise computer industry. Half inch open reel tape drives have featured in many movies over the years, in some cases long after being obsolete. Half inch open reels are rarely used, although many half inch tape reels are held in storage, containing archived data, which may require data conversion or data recovery when the stored data is required.

History of Half Inch Open Reel Tapes

IBM’s 7 track recording format stored 6 bit values plus a parity bit, adequate for storing textual data until the early 60’s when a replacement was required. The IBM System/360 was introduced in 1964 a 9 track format, which could store 8 bit values in parallel with the calculated parity bit.

Many advances were made during the next three decades such as increasing tape speed and the recording density. These techniques included the use of phase encoding (PE), group code recording (GCR) and non-return-to-zero, inverted (NRZI). Originally a zero bit was indicated by a zero voltage being returned sometimes causing issues with detecting recorded data bits. NRZI introduced the idea of returning a negative voltage making it easier to detect each recorded data bit. Although these advances had enabled more data to be stored with an increased reliability, by the 90s newer tape media using smaller self-contained cartridges were capable of storing much larger quantities of data, leading to the decline of the half inch open reel tape.

Issues with Half Inch Open Reels

Until auto loading tape drives were introduced, loading a half inch open reel could be a complicated process. The tape media is threaded around several guide wheels and across the read/write head, which has proved robust, with few tapes ever suffering an alignment issues or being damaged by the drive mechanism.

The deterioration of the lubrication layer deposited on the surface of the media, is the source of the biggest problems that are seen with half inch open tape media. The lubrication layer will be sticky when it deteriorates which can cause it to stick to the read/write head. All half inch open reel drives feature a safety cut-off which will stop the tape when the tension becomes too high, ensuring no further damage can result. The read/write head will usually become clogged and dirty, with damage resulting to the part of the tape which stuck to it. Even if the media does not stick, if the lubrication layer starts to clog the read/write head it can cause read errors to occur.

Data Recovery and Conversion from Half Inch Open Reels

Many examples of half inch open reel tapes which are seen, even if stored correctly are now suffering the deterioration of the lubrication layer. This means that most half inch open reel tapes will require data recovery. Depending on the state of the media the recovery process can be extremely complex. When the media is in poor condition it will usually require manual intervention by the data recovery engineer to ensure the media streams smoothly.

A well-known but last resort method for treating the lubrication breakdown issue is to back the tape media. Once this process has been undertaken there is only one chance to successfully read the data from the media, as the magnetic recording is destroyed. This process is therefore rarely done until all other non-destructive data recovery techniques have been explored.

JBOD and Windows 10 Storage Spaces

Many motherboards, storage controllers and even standalone multi-disk units support JBOD (Just a Bunch of Disks) which allows multiple disks to be attached to a computer and presented to the host operating system as a single drive. Windows 10 has introduced a facility called Storage Spaces, which allows unallocated storage space on any attached disks to be combined together to create a single data volume.

Neither of these include any fault tolerance or redundancy and may complicated the data recovery process in the event of even one drive failing, particularly when Storage Spaces has been used in simple mode. In concept these appear to be good ideas, as they allow large volumes to be created, but it puts any data stored on them at risk. Storage Spaces has replaced a similar system which was available in some older versions of Windows.

Data Spanned Across Disks

Apart from being able to create a single large data volume, using a JBOD configuration or Storage Spaces in simple mode does not provide any advantages over any other method, even setting up a set of hard disks as a RAID 0 array.

If you wish to use such a configuration it is important that all data being stored is regularly backed up to ensure that in the event of failure, your data can be restored without resorting to data recovery, which may be a complex process. Determining the order of spanned sections of drives can sometimes be difficult to determine.

Storage Spaces Mirroring and Parity

Storage Spaces does provide the possibility to configure mirroring and even parity, which uses a RAID 5 scheme. These configurations are preferable to using the simple mode, which spans a volume across different drives.

Mirroring allows the use of two or even three drives, which provides the maximum possible redundancy, but as it is controlled by the operating system will use some CPU. The use of RAID 5, especially through the operating system poses a much higher risk, but still preferable to no redundancy at all.

Data Recovery from JBOD or Storage Spaces

The use of the RAID 5 configuration or mirroring through Storage Spaces provides a high level of recoverability in the event of failure. The use of simple mode or a JBOD provides no fault tolerance and the chances of successful data recovery is determined by the level of damage which has been suffered to the failed drive.

If you require a larger data volume a better option to Storage Spaces is to install a dedicated RAID controller. If you are using a standalone unit, it is much better to use a RAID level which provides fault tolerance, thereby increasing the chances of a successful data recovery in the event of a failure.

Exabyte Tape Cartridges

Exabyte Corporation pioneered the 8mm magnetic tape data storage backup format for use on computer systems. The format was also known as Data8, in many cases abbreviated to D8 and also sometimes written as D-Eight. The cartridges are mechanically the same as tapes used in camcorders and 8mm video format recorders.

Until the development of the AIT data cartridge, Exabyte were the sole vendor of 8mm format tape drives. Exabyte Corporation was created with the aim developing the 8mm video format to be suitable for storing digital data. Using the available 8mm video tape technology they built a reliable mechanism and data format. The last Exabyte data cartridge, the Mammoth-2 was developed in 1999, making them obsolete and usually only seen for data conversion or data recovery when old archive tapes fail to restore.

Exabyte Data Cartridges

Exabyte cartridges used Metal Particle (MP) tape, first developed in 1987 with the EXB-8200 drive range was capable of storing up to 7GB of data using the EXB-8205XL drive using software compression on a 112m tape cartridge. The earliest models did not feature high-speed search, an important feature introduced with the EXB-8200SX drive. The EXB-8500 drive released in 1990, improved the data transfer speed and added hardware compression with the 8500c model.

The EXB-8505 drive introduced in 1992, further improved the data transfer speed, also increasing the capacity using a 112m tape to 10GB. Two years later the EXB-8505XL was introduced to allow data to be written to the newly developed 160m XL data cartridge, allowing 14GB of data to be stored. The EXB-8700 introduced a desktop top loader in 1995 and the Eliant 820 in 1998 failed to add any new features, probably due to the introduction of the Mammoth tape cartridge, leaving the Exabyte range of drives behind the competition.

Exabyte Mammoth Tape Cartridges

The Exabyte Mammoth tape cartridges use Advanced Metal Evaporated (AME) tape. The Mammoth drives provided read-only capability for data write to MP tape cartridges. The EXB-8900 drive was introduced in 1996 was capable of storing 20GB of data in native format on a 170m data cartridge. The EXB-8900 tape drive featured an LCD for displaying the status of the drive.

The Exabyte Mammoth-2 (M2) introduced in 1999 also made use of AME tape cartridges, which introduced an integrated 2m cleaning tape header, named Smart Clean. Three new cartridges were introduced, the 75m AME (20GB Native), the 150m AME (40GB Native) and the 225m AME (60GB Native) for use in the drive. The Mammoth-2 drive was capable of writing to AME media used in the original Mammoth drive, but unable to read the original Exabyte data cartridges.

Exabyte and Mammoth Data Recovery and Conversion

The Exabyte and Mammoth data cartridges are rarely used, except for some legacy systems. Most data cartridges of these types contain archive data, normally only required when specific archived data is required, often as the result of an E-Disclosure order. Such data should be transferred to new media on a regular basis, as the tape media will slowly deteriorate over time.

With the lifespan of most Exabyte and Mammoth tape cartridges having expired, it is all too common for a cartridge sent for data conversion to require data recovery, due to the presence of a media flaw. Such tapes should only be handled by a professional data recovery company who can handle the extraction of data blocks from damaged media and have the required knowledge to abstract the data files from the backup format held on the tape cartridge.

Tape Has Unspooled

In general tape data cartridges have a high level of reliability, but when problems do occur it is often when attempting to restore your data. Fortunately, the tape media becoming unspooled leads to the data cartridge being unusable and for cartridges using a single spool, the tape drive will need to be repaired.

If the tape media unspools into the tape drive and the data stored on it is important, the tape drive should be sent for data recovery, before it sent to be check for any damage which may have occurred. It is also best to send the data cartridge, even if you believe it is empty, as it may allow us to determine the cause of the problem.

Unspooled Tape Media

Fortunately, it is rare for the media used in cartridges such as DLT, Super DLT and LTO data cartridges to unspool into the drive. No attempt should be made to remove the tape media from the drive, as it must be removed carefully to avoid any damage occurring. This is a job best left to a professional data recovery specialist.

There are two reasons for tape media to become unspooled from a cartridge which uses a single spool, either a fault in the tape drive “end of tape” detection circuit or a problem with the media itself. The most common method for determining the end of the media is using sets of holes, which are detected during the movement of the tape, but a failure to detect them will result in the media spooling off the cartridge.

One set of media which uses two spools, such as Quarter Inch and Mini-QIC data cartridges detects the end of the media using the same method of holes in the media, with light shining through a prism fitted in the cartridge. For cartridges such as DAT and AIT cartridges the media is fixed each spool and relies on the detecting information in the tracking area. When rewinding the tape, it will often wind tight using media fixed to the empty spool to stop the tape. A failure of either will result in all the media being spooled on only one of the spools.

Unspooled Tape Data Recovery

The data written to a tape which has unspooled should be unharmed, although if it occurs when writing a backup, the dataset will be incomplete, but all files backup up to that point should be safe. If the media itself has been overused, there may be damage to the data stored on the media, which is why media rotation is extremely important.

Never attempt to fix the problem yourself, as it may result in further damage. In many tape data cartridges, the end of the media is not affixed to the spool, which is an important safety feature. Using sticky tape to the fix the media to the spool could result in the further damage occurring to the media, particularly if the end of tape detection mechanism has failed, either in the data cartridge or the tape drive. Such actions could result in the media becoming tangled. Always send any unspooled data cartridge for professional tape data recovery.

Lost RAID Configuration

If you RAID configuration is lost or deleted, it is important not to panic and make an ill-advised attempt at recovering it that could put your data at risk. To determine the configuration of a RAID array usually takes a combination of experience and an in-depth knowledge of the underlying file system, a task which should be left to a data recovery expert.

There are several ways in which the configuration can become lost such a hardware failure, logical corruption of the configuration data or accidental deletion. In all cases you should immediately contact a professional data recovery company, who can guide through sending your hard disk drives so that your files can be recovered.

Hardware Failure

Some RAID cabinets store the configuration in a chip on the controller board, which is accessed when the system is powered on. The downside of this approach, is that should the controller board or the chip fail, and need to be replaced, the configuration will be lost. Attempting to reconfigure the RAID array would risk damaging the data contained on the drives.

Logical Corruption

Many dedicated RAID arrays and those created through the operating system, will usually use the logical volume manager (LVM) for storing the information used to determine the configuration at boot time. This approach keeps the configuration closely tied to the RAID, such that the need to replace any hardware should not have any effect on this data. Should the LVM become corrupt due to malicious software or an unreadable bad sector, the operating system will be unable to mount the RAID volume.

Deleted RAID Configuration

Deletion of a RAID configuration can happen as a malicious action, although in most cases it is simply down to user error, often caused by attempting to hurry when reconfiguring systems. The consequences of this are very much the same as those due to a hardware failure or logical corruption, in that the RAID volume will become inaccessible.

Never Reconfigure the Array

Even if you were told at the time the RAID array was installed that it contains a specific configuration, never attempt to reconfigure using that information. We have seen many cases where a customer has been told they are using a particular RAID configuration, but upon inspection it is apparent a totally different one has been used.

Reconfiguring the RAID may have a small chance of success, but should it be incorrect, it may render your data totally inaccessible, or in the best case, data recovery may be possible, but a much more complex process than it should have been.

RAID Data Recovery

As with any hard disk drive which arrives, our data recovery specialists will secure a sector-by-sector image copy of each drive before the full recovery process can be completed. Our RAID data recovery engineers inspect the images to determine the RAID configuration using their in-depth knowledge of file systems. In the case of losing a RAID configuration, our success rates are extremely high.

Flood Damaged Laptop Carlisle

”When my laptop was damaged in the recent floods, a friend recommended I contact DiskEng. Very impressed with the professional service and excellent advice. Thanks for recovering my important files.”

TL Althwaite, Carlisle Read more

Operating System Crash or Errors

A system crash or random application errors are an all too common occurrence, the root cause of which can be due to one more differing problems. Such problems can range from any number of hardware faults through to software and logical errors, affecting drivers or the file systems. Repeated attempts at rebooting the computer are unlikely to fix the problem unless you can find the real cause of the problem. Should the computer reboot it you may be lucky, but there is a good chance that the problem may reoccur due to an underlying issue.

If your computer is crashing regularly or unexpected software errors start to occur, it is important to take action before the safety of your data is put at risk. Repeatedly rebooting a computer which is suffering from crashes could very likely risk make the problem worse, and make data recovery a more difficult process.

Hardware Problems

A hard disk drive problem is the most likely to put your data at risk, although a failure of a memory module could have the potential to cause corruption. Determining the cause of a hardware issue is important, as some could lead to further failure, such as the failure of a cooling fan, which may lead to a reboot due to the computer becoming too hot.

If the hard disk drive is failing, it is important to ensure that your data is backed up before data recovery is required. Although the occasional computer crash can happen with no problems occurring, it is easy to become complacent, such that an increase in crashes is not seen as unusual.

Software and Logical Data Corruption

Some crashes may be caused by driver errors, software corruption or file system damage. Driver issues and software corruption will most likely be inconveniences, which should be resolvable by their reinstallation. Some file system damage may be the consequence of a sudden reboot, through a power failure or a system error, which is usually fixed without any problems when the file system is mounted.

File system damage caused by unreadable bad sectors or malware damage in many cases cannot be easily fixed, and often an attempt to fix it may cause further corruption of the file system. Most users will install anti-virus software, which will usually provide protection, but does not guarantee the safety of your data.

Crashes and Data Recovery

If your problem appears to be due to either malware problems or a failure of the hard disk drive, it is important to power your system down and seek professional help. In such a case any attempt to reboot the system, even if it succeeds could be causing further damage, which could cause loss of data.

In most cases data recovery should be possible as damage to the file system is usually only minor. However if the corruption becomes too severe the level of data recovery success will be affected, as important data structures and even file data may be too damaged. All computer systems and file systems are at risk when this occurs, so it is important to act before it is too late.

Failure After Power Outage

Failure of the power supply or a power cut can result in damage to electronic components in a computer. When the power fails there is a small chance of a power surge occurring and also when power is restored.

If a failure occurs it is usually just a matter of inconvenience waiting for the damaged component to be easily replaced. However, if the hard disk drive has failed, it is not a simple case of replacing the drive and being back up and running. If the hard disk contains important data, it should be sent for data recovery, as it requires professional expertise to gain access to the files.

Power Surge Damage

Electronic components are only capable of surviving voltage and current levels within certain tolerances. A power surge can lead to a situation where these levels are exceeded, which can cause damage resulting in a failure of the component.

Any single power surge may not necessarily result in an instant failure, but as with damage caused by excessive temperatures, it is cumulative. The most common component to fail is the power regulator, but any other can be damaged. A failure of the firmware chip or maintenance area would make the process of data recovery much more complicated.

Controller Board Rebuild

In some cases it is possible to repair the damaged component or components, which allows the data recovery engineers to secure a sector-by-sector image of the hard disk drive. If the damage is severe, it will require a donor drive to be used, the controller board from which allows an image to be secured.

This is a process which should only be undertaken by a qualified data recovery engineer using specialist knowledge and equipment. Any attempt by a home user at replacing components or using a donor board risk causing further damage which was not present when the drive failed.

Power Surge Data Recovery and Protection

Our success for recovering files from hard disks which have failed due a power surge are very high, providing no risks have been taken which may have caused damage through do-it-yourself data recovery attempts. If the drive was operational at the time the power surge occurred it is possible for there to be some data which was not committed to disk, any such damage is usually very small, often only causing damage to temporary files.

Surge protectors typically are cheap to buy, but not all are good at eliminating the issue from affecting your computer. A more expensive option, but one which should provide fullest protection is to install an uninterruptible power supply (UPS) which will also allow the computer to undertake a controlled shutdown in the event of a power outage. It is important that any UPS is regularly tested, as a non-working UPS may be as bad as having no protection at all.

Failed (SSD) Solid State Device

Once the price of SSD drives made them a viable choice, their popularity has increased at a fast pace. They provide a major boost in data transfer speed, use less power, combined with a perceived durability advantage over spinning hard disk drives. It is true that they are almost immune to impact damage apart from the severest knocks.

It is recommended that an SSD is only used for the operating system and program files. This is because when an SSD does fail, data recovery is a much more complex procedure, with a lower chance of success. However, if the user areas and desktop contents located on the boot volume are used to store files, as is quite common, important data may be present on the SSD.

SSD Read and Write Limitations

Each storage bit in solid state memory is liable to become damaged after a certain number of read/write accesses. In most cases this is not an issue, as this is not only a high number, but the drive performs automatic balancing to enhance the lifetime of the device. An SSD will under normal remain fully operational for the duration of computer’s life.

Some applications however can cause excessive random data access, such as some video manipulation programs, leading to a rapid increase in memory access, thereby considerably reducing the lifespan of the SDD.

Other SSD Failure Mechanisms

As with any electronic device containing sensitive components SSD’s are susceptible to damage from heat and power surges. Either of these problems may cause damage to any of the electronic components. A power surge is most likely to cause a failure of the power regulator, whereas heat causes a slow build-up of damage, which will eventually become apparent when a fault occurs.

A sudden power failure besides causing a possible power surge, may lead to another side-effect on certain SSD devices. Ideally during the last moments of power an SSD should commit all outstanding memory changes. In some devices this may not occur and could lead to corruption of data, which could lead to a failure of the file system.

SSD Data Recovery

In the event of a severe SSD failure data recovery must be undertaken for a professional data recovery company using the correct procedure and specialist electronic hardware. It may be necessary to directly recover the raw data from each memory chip in the SSD as the first process during data recovery.

Each SSD manufacturer tends to use their own proprietary storage format and data interleaving techniques which are still subject to change as new devices are developed. New techniques quite often need to be developed in-house to handle the most recent changes in SSD technology.

Data Volume Reformatted

An all too common mistake is accidentally reformatting the wrong partition. The extent of the data lost depends upon the file system being used and the volume of data written to the new volume afterwards.

In all cases no further data should be written to the volume, as the only method of retrieving the previous files is through data recovery. Some file system types may give very little chance of recovering data, while some will do minimal damage to the old data, unless new files have been copied to the volume.

System Areas Reinitialised

When a file system is reformatted the system areas are reinitialised, which creates a clean data volume. In file systems such as NTFS and XFS only those system areas necessary to produce a working volume are reset. This allows the majority of files to be recovered from a newly reformatted NTFS and XFS data volume, with extremely high success rates possible for these types of data volume.

For a FAT file system, this includes clearing the File Allocation Tables, which destroys the allocation for all files and directories. Other file systems such as UFS, and Linux Extended volumes, all inodes are deleted in the process, rendering the previous file and directory structure inaccessible. For HFS and HFS Plus data volumes, the default catalog and data extent areas are deleted. While some parts of the catalog may remain, in practical terms, this also renders the previous file system data structure inaccessible.

Writing New Data Files is Destructive

Any new data written to the volume will lead to further damage of vital data structures with the possibility of overwriting file allocation or contents. The more data that is written to the newly formatted volume the higher the level of damage that will occur to the previously stored data files.

Reformatted Data Recovery Options

In the best cases such as a newly reformatted XFS or NTFS data volume an almost complete recovery can be made. However, once data is written to the volume, the level of the data recovery possible is reduced.

However for classic Unix style file systems and HFS Plus data volumes, the file system structures and metadata is lost. The only option available in such situations is a raw data trawl of unused space looking for the start of files with known data signatures. This solution will only be successful for files where the data has been stored contiguously.