Mark:
2) Interrupt overhead - I cannot think of any reasons why there
should be any significant difference between the interrupt overhead
of a script-driven EIDE vs. SCSI ?
Have you got any info on this? I personally haven't observed this behaviour.
3) Cache management - A SCSI drive has integrated cache management
which an EIDE drive does not. The host would have to perform this
activity in an EIDE arrangement, which would be an increased overhead.
However, my experience of ADVANCED operating systems (not Mickey-soft)
is that the disk driver software likes to have good control over all
of the disk transfers - i.e. it has it's own cache/track/etc., management
routines, which somewhat minimises the benefit of the integrated SCSI caches.
You got me there. I haven't put my hands on a real O/S (ie. Unix) that use EIDE I/O subsystems. I don't believe NT offers any real improvement in this area when compared to the regular MickeySoft O/S.
So, yes I agree that EIDE places slightly higher demands on the host,
but only in respect of the disk cache
With easily 30-60% difference between a good SCSI drive and a run of the mill CDROM (sorry I'm stressing CDROM here but all home PCs have one and they use them a fair bit) I believe there's a visible difference.
With more people getting scanners, how about having a look at this URL to see what Adaptec says. adaptec.com
also check this one for UDMA related info: adaptec.com
One more thing I keep forgetting is Adaptec's network products, ATM and Ethernet related. Unfortunately, I'm not familiar with their penetration of these products in the general marketspace. Any info, market wise, any of you can provide on this?
Mauro. |
