Browse Prior Art Database

Evaluating Relative Alignment of Diskette Drives

IP.com Disclosure Number: IPCOM000046580D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 70K

Publishing Venue

IBM

Related People

Beebe, WE: AUTHOR [+2]

Abstract

Track alignment servoing is a feature not often found on low-end diskette units used with keyboard display word processing equipment. Without this feature, it is necessary that different diskette drives be in alignment for matching the need to run diskettes on different drives. By using the identification field portion in addition to the data field portion of a record in the test, the granularity of the measurement is increased as well as the value of the measured result. Separately using identification field and data field is accomplished by decoding the return status without involving a different recording technique. Program-based alignment procedures using pre-recorded tracks have been used in the diskette drive manufacturing facilities for many years.

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Evaluating Relative Alignment of Diskette Drives

Track alignment servoing is a feature not often found on low-end diskette units used with keyboard display word processing equipment. Without this feature, it is necessary that different diskette drives be in alignment for matching the need to run diskettes on different drives. By using the identification field portion in addition to the data field portion of a record in the test, the granularity of the measurement is increased as well as the value of the measured result. Separately using identification field and data field is accomplished by decoding the return status without involving a different recording technique. Program-based alignment procedures using pre-recorded tracks have been used in the diskette drive manufacturing facilities for many years. These procedures require that the alignment tracks be recorded with high precision and that the diskettes containing these tracks remain in a carefully controlled environment (temperature, humidity, age, etc.). Using the same basic manufacturing facility technique while shifting the emphasis from measuring absolute alignment to measuring drive-to-drive alignment compatibility provides improved knowledge of the alignment of one diskette drive relative to other diskette drives. This knowledge can be used to determine whether diskettes produced on one drive are readable on other drives. This measurement is accomplished by providing (1) a diskette containing alignment tracks, (2) a program that returns "figures of merit" or "return codes" for easy comparison, and (3) a special procedure. This procedure includes: using one and the same diskette to test all drives and, assuming all drives are located in similar environments, running the tests quickly while the alignment diskette and the environment are stable. The return code number reported by the alignment program is a measure of the alignment of the drive relative to the alignment diskette, and is used for comparison purposes. Since the same diskette is used in all drives and the drives are in similar environments, the environment affects all return codes equally. The user will be able to select the misaligned drive(s) from the group of drives based on the return codes. Valid alignment return codes are +1, 0, -1, and they are used as follows: Differing return codes indicate differences in alignment, not necessarily incompatibilities. Return code differences of not more than one, e.g., +1 and 0, -1 and 0, are generally compatible. Return code differences greater than one, e.g., +1 and are generally not compatible, and adjustments should be performed on the smallest number of drives to make them compatible with the rest. There are other results besides return codes, and they are status reports of gross misalignment or insensitivity that require no further analysis or comparison. Improvements result from an alignment test which incorporates four alignment stress tracks written at two sym...