CMD640, the California Micro Devices Technology Inc product 0640, is an IDE interface chip for the PCI and VLB buses. CMD640 had some sort of hardware acceleration: WDMA and Read-Ahead (prefetch) support. CMD Technology Inc was acquired by Silicon Image Inc. in 2001.

Hardware bug

The original CMD640 has

data corruption Data corruption refers to errors in computer data that occur during writing, reading, storage, transmission, or processing, which introduce unintended changes to the original data. Computer, transmission, and storage systems use a number of meas ...

bugs, some of which remained in CMD646. The data corruption bug is similar to the bug affecting the contemporaneous PC Tech (a subsidiary of Zeos) RZ1000 chipset. Both chipsets were used on a number of motherboards, including those from

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

. Мodern operating systems have a workaround for this bug by prohibiting aggressive acceleration mode and losing about 10% of the performance.

References

External links

File containing technical information, FAQs, and tests regarding the corruption issues

Linux's description of how it deals with the CMD640 corruption

* * ttp://mindprod.com/jgloss/eideflaw.html EIDE flaw AT Attachment Hardware bugs Integrated circuits {{compu-hardware-stub