Solution to Poor Data Write at Low Temperatures in Magnetic Data Storage Systems
Original Publication Date: 2001-Aug-01
Included in the Prior Art Database: 2003-Jun-12
The write capability of hard disk drives can degrade at cold temperatures (below 15-deg Celsius) due to coercivity increase of the media. We propose a technique by which the drive temperature is ensured to be 15-deg C before the drive’s write function is activated. Our proposal is that, upon power-up, if the drive is detected to be below 15-deg C, thermal heating would occur first to take the drive to 15-deg C. Since most drives should function reasonably well down to 5-deg C, and 15-deg C is about the lowest temperature at which the write function is ensured for present drives in development and production, this thermal heating would only be at most a 10-deg C increase. Only after this minimum temperature is reached will the drive be allowed to be used for normal operation. The requirements for this proposal are: Temperature sensor in the drive (already in most drives currently) Microcode modification to account for this power-up requirement Thermal heating capability, as described below Described here are six different options for implementing the thermal heating: 1. Deposit heating coils on media substrate, then deposit magnetic materials over them (heating coils embedded in the media and linked to spindle for one end of contact, and outer edge of media connected to movable contact to complete the circuit for coil heating). 2. Deposit coils in "dummy" disks (one disk below the stack, and one above the stack) takes advantage of thermal conductivity of spindle (thermally connecting one heated "dummy" disk to a cooler disk).