International Business Machines Corporation

Robert A Klem

Alan A Fennema

Nhan Xuan Bui

Brian Gerard Goodman

Timothy Keith Pierce

Updating firmware stored in a rewritable non-volatile memory as a plurality of firmware code images having position dependent code. A plurality of update code images are made available that have position dependent code specifying positions of a rewritable non-volatile memory, such that each update code image is suitable for replacing a different stored code image. A computer processor determines which stored code image is to be updated; and selects the one of the plurality of update code images that has position dependent code suitable for replacing the code image to be updated.

Firmware updating

In an optical disk recorder, during the sensing of closely-spaced, position-indicating, machine-sensible indicia, a first peak of a track error signal is detected. In response to the first peak being detected, a half-track counter is decremented from a value which depends upon the position of the destination track relative to a current track. In response to the occurrence of a selected value of the half-track counter and the presence of a zero crossing of the tracking error signal, a first timer is activated to mask any defects occurring during the selected first half cycle of the last cycle of the tracking error signal. The half-track counter is again decremented in response to a second peak being detected and the occurrence of a next-to-last zero crossing of the tracking error signal and a second timer is then activated to mask any subsequent defects occurring during the second half cycle of the tracking error signal. The seek operation is terminated when the count value in the half-track counter equals zero and a final zero crossing is detected. Thereafter, a track following operation is activated.

Masking of tracking error signal abnormalities due to media defects

A focus acquisition system includes providing a focus offset and changing the offset symmetrically for each measurement cycle. The amplitudes of the readback or tracking error signal are sensed and compared. When the amplitudes of the tracking error or readback signal is different at each of the offsets, then a new measurment cycle is performed after calculating a new offset value. The process is repeated until the temporary measurement offsets result in readback amplitudes that are substantially equal. A best focus is then indicated as being a position in which small defocussing will not substantially degrade the quality of the readback signal.

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Tucson, AZ, United States of America

Robert A Klem