Quarter inch cartridges (QIC) often called “quick” were developed by 3M in 1972, mainly for use on mainframe and mini-computer systems. All quarter inch cartridges store data using the linear serpentine recording format with the read/write head moved up and down using a servo motor. The tape is advanced at a constant speed using a continuous belt which is in direct contact with both tape spools and a drive wheel which is driven directly using a capstan.
Quarter inch cartridges are often referred to as metal backed tapes due to the thick aluminium baseplate which is common to each tape. Following the development of the Personal Computer (PC) a smaller version was developed, aimed particularly at small businesses and home users, called the Mini-QIC tape (using 8mm wide tape) which used the floppy drive interface. In 1992 in order to increase the available capacity on Mini-QIC tapes, 3M developed the Travan cartridge range which uses media 8mm wide. These are now all obsolete tape cartridges, but examples are still in use or hold important data, so there is still a requirement for data recovery.
Quarter Inch Cartridge Design
A solid metal baseplate usually made of aluminium forms the base of the tape cartridge providing rigidity. The two tape media spools are located upon two pins solidity fixed to the baseplate, with further guide pins and the drive wheel also attached to the baseplate. A wheel inside the drive mechanism directly contacts the tape cartridge drive wheel, which in turn moves a rubber band which moves the tape spools through direct contact.
Unlike many other tape formats, the tape media is not physical affixed to the tape spools. A series of holes at specific intervals on the tape are used to detect the end of media in both directions, which are detected via a 45 degree mirror onto which light is shone. The cover over the tape is a plastic shell, which in general translucent with the Travan range being the main exception. Unlike DLT and LTO media, the data is recorded in a genuine serpentine fashion, with the first track generally being at the bottom edge of the media.
QIC Storage Capabilities
The first QIC tape format released in 1972 was the DC300 which contained 300 feet of tape and capable of storing 200 kilobytes of data. Over the years the number of tracks was increased along with the length of the tape and the magnetic density of the media, allowing a significant increase in the storage capacity. The last generation the Scalable Linear Recording (SLR) tapes developed by Tandberg in 2005 are capable of storing 70GB of raw data.
The mini-QIC cartridge drives developed to fit into a 3.5 inch drive bay were initially capable of storing 40MB on a DC2000 using the QIC-40 format. The QIC-80 format allowed a further increase but it was the development of the Travan series by 3M which allowed a significant rise in storage capacity. The Travan TR-1 was capable of recording 400MB when it was released in 1995. The TR-7 was the final generation which was released in 2002 and capable of storing 20GB. Iomega released a similar series of tape cartridges based on the same form factor, the Ditto and DittoMax data cartridges, using a proprietary format. HP Colorado drives also used a proprietary version of the Travan format.
QIC/Traven Problems and Data Recovery
The rubber belt used for transferring the tape between the two spools can cause problems, particularly in the mini-QIC cartridges. The biggest problem is due to the belt being liable to slippage which can cause either the tape to move up or down, leading to uneven winding, or worse result in the tension of the tape to either increasing or decreasing. If the tape becomes unevenly wound, it can cause the tape to rub on the case, which may lead to resistance, and in the worst cases the tape drive capstan can damage the drive wheel in the tape cartridge. If the media tension increases it may lead to the tape becoming stretched, which can lead to alignment problems in that section of the tape. If the media tension decreases however, the result can lead to the tape becoming creased, or in the worst case become tangled around something it shouldn’t. Such a situation can rapidly destroy a large section of the tape.
The common issue we seen with QIC and Travan tape cartridges is where the tape have unspooled at one end. This can happen due to a failure of the sensor, damage to the alignments holes in the tape media or damage to the mirror. It is quite common to attempt a repair when this occurs, but these have been seen in many cases to cause huge problems, especially if the media is physically attached with sticky tape to the spool. If this is done and the drive again fails to detect the end of the media, it will attempt to continue spooling the tape, which will then cause tape to be forcibly removed from full spool, which will cause a large section of the tape to become tangled. Data recovery and data conversion from these types of data cartridge should only be undertaken by a professional data recovery company with extensive knowledge and experience.