Method and apparatus for predicting capstan slip in tape drives utilizing belt-driven tape cartridges

A method for predicting tape transit errors in a belt-driven tape cartridge during operation in a tape drive, wherein the tape transit errors are caused by slipping of an elastomeric tape drive roller on a cartridge belt capstan, the method comprising:

• determining the normal force of the elastomeric tape drive roller against the cartridge belt capstan and the angular drive force of the cartridge belt capstan which results in capstan slip;
• extrapolating the normal force and drive force resulting in the capstan slip to a critical tape velocity value;
• designating a tape velocity threshold value at a higher velocity level than the critical velocity value;
• monitoring a tape velocity within the belt-driven tape cartridge;
• and
• providing a warning of an imminent slip condition where the tape velocity has decreased to the velocity threshold value.

A method for predicting capstan slip conditions between a tape cartridge belt capstan of a belt-driven tape cartridge and a drive roller of a tape drive, and for determining which of the belt-driven tape cartridge or the tape drive is defective, the method comprising:

• determining a critical tape velocity value corresponding to a critical slip condition based on a relationship between a drive force for rotating the cartridge belt capstan and a normal force of the drive roller against the cartridge belt capstan;
• selecting a threshold tape velocity value corresponding to the drive force and the normal force at a point where the relationship between the drive force and the normal force would not encounter the critical slip condition;
• monitoring a steady-state tape velocity representative of the drive force and the normal force during operation of the belt-driven tape cartridge in the tape drive;
• providing an imminent capstan slip indication when the steady-state tape velocity reaches the threshold velocity value, whereby the imminent capstan slip indication is provided prior to occurrence of the critical slip condition;
• replacing the belt-driven tape cartridge, in response to the imminent capstan slip indication, with a test cartridge having a stationary capstan in place of the cartridge belt capstan;
• applying a test torque to the drive roller of the tape drive;
• monitoring for rotation of the drive roller;
• and
• designating the tape drive as defective if rotation of the drive roller is detected.

A tape drive for predicting capstan slip conditions during operation of a belt-driven tape cartridge, the tape cartridge having a rotatable belt capstan to impart motion to an elastomeric belt which moves the tape within the tape cartridge, comprising:

• a drive motor coupled to rotate a drive capstan;
• a drive roller, coupled to the drive capstan, having an elastomeric surface to engage the belt capstan, wherein a normal force of the drive roller against the belt capstan in view of an angular drive force of the belt capstan causes the belt capstan to rotate;
• and
• a processor configured and arranged to monitor a nominal tape velocity, and to provide an imminent capstan slip notification when the nominal tape velocity reaches a tape velocity threshold value corresponding to a relationship between the drive force and the normal force indicative of imminent, yet unencountered, capstan slip.