Modern tape technology leads the industry in error detection and correction. Many different error-correction schemes, such as the use of parity, cyclic redundancy check (CRC) codes, checksums, Reed-Solomon codes, Cross-interleaved Reed-Solomon (CIRC) coding and more, can recover data from damaged media.
More recently, Linear Tape-Open (LTO) cartridges brought several improvements to backup tape cartridges by improving the tape leader and adding a Cartridge Memory chip (LTO-CM) to each cartridge. The CM chip stores a variety of metadata about the lifetime use of the cartridge. Information such as remaining capacity, total number of reads, writes, loads, error codes and even information about the tape drives used to read or write this cartridge over its life, is stored on the CM chip.
Every LTO drive has a CM reader in order to evaluate the information stored on the CM chip. Media manufacturers like Fujifilm Corp., Imation Corp., Maxell and several third-party vendors have products available to analyze the CM chip data. Some CM monitoring tools like Hi-Stor StorSentry work in-band. Others, like the Crossroads Systems ReadVerify Appliance (RVA), work out-of-band. Some CM monitoring tools focus on managing the tape cartridges themselves, while others provide a service that incorporates management of the entire environment, including library service, drive repair, configuration and performance tuning. All of the leading library vendors provide some form of management/monitoring service and/or software as well.
Tape cartridges won't to turn red, send out emails or blink while sitting on the shelf, but adding metadata and monitoring tools to the cartridges can help detect problematic tapes and reduce the occurrences of data loss.
This was first published in April 2010