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Exabyte is the original brand in high capacity 8mm magnetic tape storage technology. Exabyte Corporation introduced helical scan recording technology in the late 1980s and was widely recognised at the time as a reliable, cost effective format which offered high speed read/write capabilities and a wide range of native capacities and formats. The Exabyte 8mm data storage tape was the first time that helical scan technology had been used for data storage, and was mechanically identical to the widely used 8mm video format technology found in the Professional Media and broadcasting market. Due to its heritage with Sony, Exabyte 8mm technology shares similar mechanical components found in home video systems but on a slightly smaller scale.

Helical scan is an older style method of recording data onto a slow moving magnetic tape which uses a rapidly rotating read/write head. The data is recorded onto diagonal tracks, which are at an angle to the edge of the tape. After loading into a drive, the tape is pulled from the cartridge and wrapped around the read/write head, which rotates at around 30 metres per second. While the Sony AIT family also uses the same 8mm technology as the Exabyte range, they are not compatible with one another.

In its hey-day the helical scan 8mm technology was for a time at the forefront of this sector in the market due to data transfer rates of around 240KB per second and initial storage capacity of 2.4GB. It has however, since been surpassed by linear recording technology. The newer linear recording technology allows for faster reads and writes, lower search latency, and is the technology that has been widely adopted across all sectors of data storage.

What is Linear Recording?
Linear (or longitudinal) recording is a method of recording data whereby tape is passed by a non-moving recording head. The tracks are recorded parallel to the tape edge.

Why migrate from Exabyte 8mm Technology

Exabyte 8mm data storage technology has now reached EOL (end of life). Although designed primarily for a domestic camcorder market and not for the commercial data storage market, the Exabyte format became incredibly popular in the commercial sector during the 1980s and 1990s because of its relatively low-cost drives and tape media. As a result of this popularity, a broader, more comprehensive adoption of the technology occurred than perhaps strategically suited the technology. It is only in recent years as the technology was nearing retirement (EOL), that many clients have discovered that the economic advantages of the technology heralded in the early days was now showing signs of decreased reliability also and therefore resulting in data loss.

This type of aging 8mm is now becoming the new "9 track" legacy migration requirement. Unfortunately it also comes with new issues and problems which can make it very difficult or impossible to recover data from. Traditionally, 9 track tapes have presented problems for data migration, but with the implementation of binder hardening processes, specialist software and multiple reads of exercised tapes, the data in 99% of cases can be recovered.

Data stored on 8mm technology may not be so lucky. Why? From our experience we believe there are many factors which place data stored on this technology at risk. These are as follows:

Tape Width
With the exception of 4mm DAT tapes, Exabyte 8mm tape technology is the narrowest commercial data storage tape introduced to the market. In comparison, most of the tape in today's cartridges are 25mm wide. The narrowness of the tape equates to a weaker, less robust tape that results in stress and damage more readily, particularly over time and number of physical tape loads.

Dual Reel Architecture
The dual-reel cartridge architecture of the 8mm Exabyte technology is not the most ideal form. The complexity of the configuration makes it much more susceptible to physical defects and problems such as looping within the tape spools. This inturn causes inconsistencies in the tension of the media, resulting in damage to the tape media in the form of creases, nicks, folds, crushed, stretched and snapped media. Obviously not ideal!! Closed cartridges in this format result in a "if you can't see it, you can't fix it" scenario. The now more commonly implemented open reel architecture used with LTO and 3590 media overcomes the difficulties that are encountered with forms such as Exabyte.

Limited Head Adjustments
The tape drives are limited to the number of head adjustments which can be made while reading data. If there was a skew of any kind on the original drive which wrote the data, and that skew cannot be replicated by a head adjustment on the new drive, then it is unlikely it can be recovered. In addition, the multiple reading of the tape at different head settings and the constant stopping and starting can cause stress on the tape and result in snapping or damage.

Internal Drive Settings
Certain types of 8mm Exabyte drives allowed the creation of different partitions within a tape cartridge, through the use of internal drive settings. Often these were specific to certain organisations or departments only and this information is not easily obtained or second guessed during a recovery or migration process.

No Longer Supported By Manufacturer
As a data storage technology which has reached EOL, this means that it is no longer supported by the manufacturer. In fact the original drive and media manufacturer Exabyte were bought by Tandberg in 2006. This means that there are very few new drives available for purchase, nor spares readily available for maintenance and repair of existing drives. From our own experience, even to purchase older working drives is becoming increasingly difficult. Once a common item on eBay Australia, they are now rarely seen or available.

Type of Data Held On Exabyte Technology
Using the oil and gas industry as a prime example, the type of data stored in Exabyte 8mm technology was largely processed data. This means it has had substantial value added to the raw data, and therefore small losses of data can be more significant.

Density
In comparison to storage technology which is readily available today, Exabyte tapes hold very little data. An average holding of 1000 Exabyte cartridges would now quite easily fit onto 5 or 6 LTO tapes which in addition to the main advantage of data security and longevity, also represents savings in ongoing storage and retrieval costs.

In addition, as one media cartridge can be written to on many drives, there is a higher chance of there being a compatibility issue for users with regards to data density.

Brand Differences in Media
As always in a competitive market, there were quality products and inferior quality products and by this we refer to the media brand which were compatible with this technology. Largely due to the manufacturing process of 8mm tape and how the end products were distributed for rebadging and resale, there are significant differences in the reliability of different brands. The brand of media storing your data should be an important consideration when planning for its migration to newer technology - with the inferior cartridges taking priority where possible.

How To Take Corrective Action

An audit and data migration plan, if required, should take into account the following factors:

- How much data do you have stored on 8mm technology?
- How many cartridges are there?
- How/where are they stored?
- What brands of media were used to record the data? (Some will have priority, some may last a little longer)
- What type of data is residing on these tapes? (Is it field data, processed data or other data)
- How often are the tapes tested for restoration of data? (Have you already encountered problems with restoring data?)
- Do you even still have the tape drive to read the tapes on?
- Do you have problems with your drives?

Conclusion

Exabyte technology is not considered an ideal choice for archival and backup data - even for small/medium sized organisations which generally do not have the budgets to purchase expensive, state of the art high capacity storage technology. The retired drives (and tape media) can be unreliable, are prone to physical damage and stress, and as a storage technology choice are now considered a very low capacity legacy technology.

The recommended migration path for data stored on 8mm technology is to either 3592 media, which is now industry standard within the oil and gas sector, or to LTO technology for other types of industry. With the current rise in popularity of the LTO format, this enterprise level media solution is now more affordable allowing SMB/SME users to exploit its large volume and reliability. This makes it an ideal replacement for the aging Exabyte media format. Both types of media are widely used and are readily available.