The Ohio State University

NEW DELAY‐INTEGRATION METHOD FOR MEASUREMENT OF LATERAL TAPE MOTION AND STUDY OF TAPE PERFORMANCE UNDER HIGH SPEED CONDITIONS

Derek J. Petrek
M.S. Thesis,
Department of Mechanical Engineering, Nov. 2007

ABSTRACT

Magnetic data tape is one of the most cost‐effective means of large scale information storage, and has the capacity to remain so in the future. Many challenges must be met in order to improve the storage density of magnetic tape systems and keep up with customer demands. One of these challenges is to minimize the relative motion between the read/write elements in the tape drive and the data tracks on the tape, also known as lateral tape motion (LTM). Many factors influence LTM, and care must be taken in design of both the tape drive and tape media in order to minimize the negative effects of LTM. This thesis details a study in which a new delay‐integration method is applied to LTM measurement. The advantages and disadvantages of the method are discussed, and a comparison is made with previous LTM measurement methods. The delay‐integration method is then applied to measure the change in LTM amplitude along an unsupported region of tape for several different tape samples. As many tape systems place the read/write head in the center of an unsupported region, information about the behavior of tape in this situation could be used to minimize LTM, allowing for smaller data tracks and increased storage density.

As the storage capacity of magnetic tape systems continues to increase so does the need for faster read and write access. One possible way to achieve this is to translate the magnetic media past the read/write head at a higher velocity. This increased speed can have unwanted effects on the operation of the tape drive and media. This thesis details a study of the effects that high‐speed operation at different tensions can have on the performance of the system. The coefficient of friction between the tape and head was monitored to gauge durability and wear, and lateral tape motion (LTM) was monitored using both magnetic and edge probe methods to measure undesirable tape motion. Results for five different types of tape operating at five different tension/speed combinations are discussed in order to better determine the effects that tape characteristics and operating parameters have in high speed situation.