🚀 go-pugleaf

Well, I believe that's what I said that, except I used the term multiple Process I/O
versus multi threading. Though I could be wrong, but UDMA does offer performance
gains in terms of multiple paths. Basically, if you have 2 EIDE controllers, like
most people do, then you should be able to access each controller independent of the
other. I've read in this group, but never confirmed it myself, that true DMA\UDMA
devices all act independent of each other. Which is where they make up some of their
performance on SCSI devices.

Dale

"Steven Wiser" <SLWISERR@erols.com> wrote in message
news:34a2pt4qcjol9mujmbiam5504frvnl0d9m@4ax.com...
> One more thing that I think may be important to this issue is that IDE
> is single threading in its response and SCSI is multi-threading.  This
> is to say if you have more than one thread attempting to access the
> harddrive the SCSI will allow access to both threads to read the data
> while the IDE would have one thread completely locked out.  Even more
> important when you have dual channels for the SCSI.
>
> Steve
>
> On Sat, 01 Sep 2001 04:08:42 GMT, "Dale \"Mad_Murdock\" White"
> <whiteda@home.com> wrote:
>
> >First, you really shouldn't cross post to so many different newsgroup.
> >
> >A comparison of SCSI and IDE can be rather long and drawn out depending out which
> >phase of the technology your at with each. Instead, I'll just go over the
highlights
> >and let other who so desire dive into the gory details.
> >
> >Typically SCSI has always been faster than IDE (Currently it's 160MB/s versus 100
> >MB/s), offered more devices than IDE (15 to 7) and had little impact on CPU usage
(5%
> >versus 75%). With new technologies like UDMA and the ability to add multiple IDE
> >cards, you can now come pretty close to matching SCSI functions and performance.
> >
> >SCSI also tends to be more expensive then IDE, partly because of it's advantages
and
> >partly because SCSI devices have a longer mean time between Failure\repair
> >(MTBF\MTBR). SCSI cards are able to multi process, meaning they can carry out
> >multiple I/O request at a time, IDE, I believe, is still serial based meaning I/O
> >request line up. You also need an OS like Win NT/2000/Linux to be able to take
> >advantage of Multi process I/Os
> >
> >With a normal PC, you can have 4 IDE devices. With any SCSI card you can have at
> >least 7 and with new cards 15 devices. SCSI pretty much always gives you external
> >connectors (as you probably won't find many cases that support 15 devices) SCSI
also
> >tend to have the larger drives first, but it seems in the last year or so, IDEs
are
> >really screaming by.
> >
> >SCSI allows you to go greater distances. Depending on the technologies in use, the
> >SCSI devices could be from 6 meters to 25 meters from the PC. SCSI allows you to
> >share SCSI Buses, which is used in the cluster world to allow 2 or more PCs to
access
> >the same disks or at least the same disks arrays.
> >
> >Until recently, SCSI was the only technology that offered hardware RAID features.
> >(RAID is a subject in itself) Though most home users have never had a real need
for
> >it, and the cost for a hardware raid controller is normally not worth the minimal
> >benefits (again, for a average home user). SCSI controllers also tend to have
fairly
> >large amounts of cache (or memory) on them. Most standard controllers today have
> >between 32 to 64 megs of ram, with the big boys have as much as a gig of ram., of
> >course, the cost for a 64 meg SCSI RAID controller is around $1000-3000, depending
on
> >the technology it deploys.
> >
> >SCSI is ideal in environments that needs fast large disks, performing heavy read
and
> >write request. For more home users, there is very little reason to go to SCSI
because
> >the cost is so much more than the gain, especially running in the Win9x world. But
if
> >you wanted to create a 400 Gig disks volume at the hardware level, then SCSI would
be
> >the perfect technology.
> >
> >Again, this is just kinda of skimming the surface, and their are plenty of
variables
> >to this. If you really want to know more, I would start at www.Adaptec.com and do
a
> >few searches on SCSI vs. IDE and RAID. Plenty of reading.
> >
> >HTH
> >
> >Dale
> >
> >
> >"Holy Smoke" <kissme@columbus.rr.com> wrote in message
> >news:cNYj7.37727$Iq4.18664937@typhoon.columbus.rr.com...
> >> Can you tell me the difference between them? what is their advantage, and
> >> disadvantage?
> >> what can scsi do that ide cant? (sorry, hehe, i need more info about scsi,
> >> know enough of ide)
> >>
> >> X-Post?
> >>
> >>
> >
>