-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Saturday 2006-03-04 at 18:07 -0800, Randall R Schulz wrote:
On Saturday 04 March 2006 17:03, Carlos E. R. wrote:
The Saturday 2006-03-04 at 21:10 +0100, Alain Barthélemy wrote:
Now, I tried an external DVD reader on USB port and, suddenly, I can't read the DVD's with a reasonable speed anymore. In Yast/Materials/DMA-IDE setup I don't see the DVD reader in the list.
There is no dma for usb drives. No way.
Isn't that a function of what hardware is incorporated into the system? Are you saying that no one makes a USB adaptor with DMA capability even now that there are so many high-speed and mass storage devices? You'd think there'd be a demand for such a thing.
No, I didn't say that. The OP poster wanted to activate DMA for his DVD drive on the USB, the same way it is done for internal drives on the IDE bus, with hdparm or something similar. There is no such thing. It should be possible for the designers of usb controller chips to use dma... but that is a diferent thing. Anyway, the speed of the bus is limited and fixed, dma would not increase it. It would lower the overhead on the cpu, that's all. Note: Extracting from the wikipedia: ] USB supports three data rates. ] ] * A Low Speed rate of 1.5 Mbit/s (183 KiB/s) that is mostly used for ] Human Interface Devices (HID) such as keyboards, mice and ] joysticks. ] * A Full Speed rate of 12 Mbit/s (1.4 MiB/s). Full Speed was the ] fastest rate before the USB 2.0 specification and many devices fall ] back to Full Speed. Full Speed devices divide the USB bandwidth ] between them in a first-come first-served basis and it is not ] uncommon to run out of bandwidth with several isochronous devices. ] All USB Hubs support Full Speed. ] * A Hi-Speed rate of 480 Mbit/s (57 MiB/s). ] ] Though Hi-Speed devices are commonly referred to as "USB 2.0", not all ] USB 2.0 devices are Hi-Speed. - -- Cheers, Carlos Robinson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFECuZbtTMYHG2NR9URAoVxAJ9JbKyN9TpnRPfyrUCHtaef4ta/5wCgg5HL RbXSKe/qGCiVeaMO5UJtd/Q= =EWWf -----END PGP SIGNATURE-----