On Sun, 25 Apr 2010 15:16:14 +0200, you wrote: Hi Bernd,
>To make a long story short: Jack R Ellis has had a number of drivers >developed for access to optical units and discs, most of this software >has sourcecode available. His latest is UIDE.SYS which should support CD >drives also on Serial-ATA (possibly in AHCI-mode, or just IDE-emulation). UIDE have no AHCI support, only "Native IDE" or "Legacy IDE" supported, I've asked him the reason, his answer below: [quote begin] UIDE does benefit from usually having a LOT of "rotational latency" time, between disk transfers, so the next transfer will be set up and begun long before the disk can "rotate" back to the first sector of that new transfer. AHCI tries to "help" with this by "chaining" disk commands, so when one disk command ends, the next in the "chain" can be begun without the disk driver needing an interrupt or more processing. However, AHCI requires "asynchronous" I-O, like Windows uses, NOT "one at a time" I-O like DOS uses. So, I doubt AHCI will ever see a lot of use under DOS -- I see no reason for it in UIDE, and I think other disk-driver writers will probably feel the same. [quote end] Rgds, Johnson. ------------------------------------------------------------------------------ _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
