first, let me apologize for reincarnating this thread; I assumed
that everyone realized that modern IDE is quite usable, that is,
busmastering, supports scatter-gather, CRC's in UDMA mode, etc.
> > > - ATA implementations that do tagged command queueing
> > none. but TCQ has NOTHING to do with busmastering. under Linux,
...
>
> You're not referring to my previous two mails. I'm talking about
> smoothness and CPU load. Smoothness means the system stays usable.
> Imagine page faults during CD-ROM transactions, for example.
DMA/UDMA ide has _no_ problem with CPU load, nor with page faults
during cdrom transactions. as for the disconnect feature, sure,
only a few recent IBM disks support it. if it helps you sleep,
just ignore the existence of IDE slaves entirely.
summary: current IDE disks sustain 15-30 MB/s with minimal overhead,
with cost asymptotic to $US 8/GB. current SCSI disks are even faster,
and certainly superior for many-device systems, but have both higher
entry cost (controllers), and cost 2-3x per GB.
regards, mark hahn.
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This archive was generated by hypermail 2b29 : Sun Apr 23 2000 - 21:00:15 EST