Disk Drive and Integrated Circuit Nonvolatile Memory Combined for Increased Performance, Lower Power
Original Publication Date: 2002-Jun-24
Included in the Prior Art Database: 2003-Jun-20
Disclosed is a method of improving the performance and lowering the power requirements of a disk drive by adding nonvolatile memory elements, such as FeRAM, to the magnetic head and media storage elements. Toshiba has announced that they will have 32 Mbit FeRAM sample chips by the end of 2001. The stated write access time is 35-50 nS. (EE Times, June 4, 2001 page 34). If the chips can process data that is 32 bits wide, then they can write a sector of data (512 Bytes) in 4.5-6.4 uS. Even the top-of-the-line 15K RPM SCSI hard disk drives take from 8.6 to 12.4 uS to write a sector and this does not count the average latency of 2000 uS! The 32 Mbit chip could contain 8192 512-Byte sectors. The access time of these parts is significantly improved over current (EEROM) nonvolatile electronic memory. Current nonvolatile memory, such as EEROMs, is significantly slower than accessing the rotating magnetic media, so EEROMs would not allow performance advantages over current disk drive technology. The cost per megabyte of the nonvolatile memory IC's is substantially greater than the cost per megabyte of the disk drive's current magnetic head/media storage. This higher cost is why the disk drive's magnetic head/media storage will not be replaced by memory IC's in the foreseeable future. But there are some significant advantages of these nonvolatile memory IC's and if they were to be combined with the drives' native storage, an improved disk drive could emerge.