On Tue, Jan 2, 2018 at 3:15 AM, James Cameron wrote: > On Tue, Jan 02, 2018 at 02:15:10AM +0530, Manu Abraham wrote: >> This is what I understand: >> >> #1. The old machine was slow and the I/O on the cable was okay. >> >> #2. The faster userspace I/O on the newer system, caused a higher >> data rate on the cable, which directly affected crosstalk. This >> broke communication. >> >> #3. Now, the faster machine has a virtual machine, which slows down >> all I/O. App->VM->OS->USB->serial in comparison to >> App->OS->USB->serial > > Yes, that was my theory too; which I expressed far too briefly as > a "race condition". > > There's also a different USB controller in the faster machine. There could be another aspect to the problem, too.. The new machine has a corrupt WinUSB,dll (userspace), the kernel space WinUSB.sys is intact. The Virtual machine doesn't access WinUSB.dll, but does system calls directly, for VM optimizations. As a result when the VM is in use, WinUSB.dll is not used. Just another possibility. Cheers, Manu --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .