Hi, On Mon, 2003-02-03 at 22:11, Matthias Andree wrote: > Looking at hardware and this issue, the German c't magazine recently > reported that ready-to-run computers were shipped with ATA cables that > exceeded the maximum specified 45 cm (18 in) length. These bring the > danger zone much nearer than desired... Yes, but not as much as you'd imagine. UDMA transfers are protected by a CRC between drive and controller, so if you have cable problems at the highest speeds, it is supposed to retry and then back down to a slower speed, at which the cable length requirements are relaxed. It's only if you end up backing down from UDMA entirely (to [M]DMA or PIO) that you lose the CRC. At that point, slightly-too-long-for-UDMA100 cables really don't matter, but other cable problems such as dirty connectors can make a big difference. At the higher speeds, I've actually found that it's the motherboard-side transfers which seem to be most impacted, with various chipset bugs causing things like a single lost line of DMA between the controller and main memory. Cheers, Stephen _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
