Английская Википедия:CMD640
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.
| Chip | Protocol |
|---|---|
| SiI/CMD 640 | MDMA 1 |
| SiI/CMD 643 | MDMA 2 |
| SiI/CMD 646 | UDMA 2 |
| SiI/CMD 648 | UDMA 4 |
| SiI/CMD 649 | UDMA 5 |
| SiI0680 | UDMA 6 |
Hardware bug
The original CMD640 has data corruption bugs, some of which remained in CMD646.[1] The data corruption bug is similar to the bug affecting the contemporaneous PC Tech (a subsidiary[2] of Zeos) RZ1000 chipset. Both chipsets were used on a number of motherboards, including those from Intel.
Мodern operating systems have a workaround for this bug by prohibiting aggressive acceleration mode and losing about 10% of the performance.Шаблон:Citation needed
References
External links
- File containing technical information, FAQs, and tests regarding the corruption issuesШаблон:Dead link
- Linux's description of how it deals with the CMD640 corruption
- IBM: July 10, 1998 - Warp FixPak TIPS (includes section on how to detect and mitigate CMD640 concerns)
- Шаблон:Webarchive
- EIDE flaw
