AGP speed 2X,4x,8X: What it really means!

Courseyauto wrote:

Like the extra 40 conductors in an EIDE cable which help keep crosstalk
down. That's accurate. Length of cable also. EIDE is maxed at 18" I
believe but the serial cable could be longer and run faster because of
less chance of cross talk. It's a lot easier to shield a single cable then
to shield a large number of cables like with EIDE.

If serial cable is necessary to get 1 meter out of 150 MB/sec ATA, then how
do they manage to run U320 SCSI over 25 meters of parallel cable?

Sorry, but that argument doesn't wash.

Further, SATA cables are not shielded.

PATA goes 18" because that's what the spec said and the chip designers
worked to the spec. SATA goes one meter because that's what the spec said
and the chip designers worked to the spec. U320 SCSI goes 25 meters
because that's what the spec said and the chip designers designed to the
spec. If a new PATA spec came out that required 200 MB/sec over 30 meters
on 40-wire parallel cable then the chip designers would probably have found
a way to make it work.


That's all I know and I'm sticking by it. : )

--------------------------------------------------------------------------
-------------------
I'm running a hard drive on a 36" round IDE cable with no problems. I
needed it
because it's a full tower case so the cable will reach. DOUG

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

f a new PATA spec came out that required 200 MB/sec over 30 meters
on 40-wire parallel cable then the chip designers would probably have found
a way to make it work.

I agree, but then you would still have the wide cable.

PRIVATE1964 wrote:

f a new PATA spec came out that required 200 MB/sec over 30 meters
on 40-wire parallel cable then the chip designers would probably have
found a way to make it work.

I agree, but then you would still have the wide cable.

And that's the only real benefit of SATA that I can see that is inherent in
its being serial--that narrow cable is a lot easier to route.

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

And that's the only real benefit of SATA that I can see that is inherent in
its being serial--that narrow cable is a lot easier to route.

Here's a question for you that will keep me from having to search on related to
SATA. I plan on getting a new serial hard drive soon.

I'm using a NF7-S with serial connections.
What is the maximum throughput for a hard drive connected to the serial
connection.

Is that connection spec'd for 150Mb/sec? I've read that the serial drives that
are out now are not "true native" serial drives so there is no way they could
ever hit 150Mb/sec.

What can you tell me about this please.

Thanks

PRIVATE1964 wrote:


And that's the only real benefit of SATA that I can see that is inherent
in its being serial--that narrow cable is a lot easier to route.

Here's a question for you that will keep me from having to search on
related to SATA. I plan on getting a new serial hard drive soon.

I'm using a NF7-S with serial connections.
What is the maximum throughput for a hard drive connected to the serial
connection.

Is that connection spec'd for 150Mb/sec? I've read that the serial drives
that are out now are not "true native" serial drives so there is no way
they could ever hit 150Mb/sec.

What can you tell me about this please.

There is no drive in the world that can fill a 100 MB/sec pipe. WD Raptors
have a maximum sustained transfer rate of 72 MB/sec, 7K400s max at 62.1,
Cheetah X15s max at 86. The limit is the bits per track and the rotational
speed, not the interface. So it doesn't matter whether the interface can
hit 150 or 133 or 100.

With PATA and two drives per channel, it's possible for both drives together
to fill a 150 MB/sec channel but SATA allows only one per channel so that's
not an issue.

In any case, some use a bridge chip, others don't. IIRC Seagate is not
using a bridge chip. I don't recall what WD is doing, but their Raptors
outperform any SATA drive from any other manufacturer, although the Hitachi
7K250 and 7K400 come close, so whether they're using a bridge chip or not
clearly doesn't make any real-world difference.


Thanks

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

"J. Clarke" wrote in message
...
PRIVATE1964 wrote:


And that's the only real benefit of SATA that I can see that is inherent
in its being serial--that narrow cable is a lot easier to route.

Here's a question for you that will keep me from having to search on
related to SATA. I plan on getting a new serial hard drive soon.

I'm using a NF7-S with serial connections.
What is the maximum throughput for a hard drive connected to the serial
connection.

Is that connection spec'd for 150Mb/sec? I've read that the serial
drives
that are out now are not "true native" serial drives so there is no way
they could ever hit 150Mb/sec.

What can you tell me about this please.

There is no drive in the world that can fill a 100 MB/sec pipe. WD
Raptors
have a maximum sustained transfer rate of 72 MB/sec, 7K400s max at 62.1,
Cheetah X15s max at 86. The limit is the bits per track and the
rotational
speed, not the interface. So it doesn't matter whether the interface can
hit 150 or 133 or 100.

.... apart from the burst speed which with drives with 16MB cache now can be
a significant factor, especially with video editing applications (where the
caching algorithms have a better chance because of the big files). 16MB
bursting at 150MB/s is not insigificant.

With PATA and two drives per channel, it's possible for both drives
together
to fill a 150 MB/sec channel but SATA allows only one per channel so
that's
not an issue.

In any case, some use a bridge chip, others don't. IIRC Seagate is not
using a bridge chip. I don't recall what WD is doing, but their Raptors
outperform any SATA drive from any other manufacturer, although the
Hitachi
7K250 and 7K400 come close, so whether they're using a bridge chip or not
clearly doesn't make any real-world difference.

The Raptors have a bridge chip too. They are basically SCSI drives with an
adapter chip on them.

Chip

Chip wrote:


"J. Clarke" wrote in message
...
PRIVATE1964 wrote:


And that's the only real benefit of SATA that I can see that is
inherent in its being serial--that narrow cable is a lot easier to
route.

Here's a question for you that will keep me from having to search on
related to SATA. I plan on getting a new serial hard drive soon.

I'm using a NF7-S with serial connections.
What is the maximum throughput for a hard drive connected to the serial
connection.

Is that connection spec'd for 150Mb/sec? I've read that the serial
drives
that are out now are not "true native" serial drives so there is no way
they could ever hit 150Mb/sec.

What can you tell me about this please.

There is no drive in the world that can fill a 100 MB/sec pipe. WD
Raptors
have a maximum sustained transfer rate of 72 MB/sec, 7K400s max at 62.1,
Cheetah X15s max at 86. The limit is the bits per track and the
rotational
speed, not the interface. So it doesn't matter whether the interface can
hit 150 or 133 or 100.

... apart from the burst speed which with drives with 16MB cache now can
be a significant factor, especially with video editing applications (where
the
caching algorithms have a better chance because of the big files). 16MB
bursting at 150MB/s is not insigificant.

I fail to see how it makes a difference with video editing, where you are
trying to stream several gigabytes of data.

How much real-world difference do you see between a drive with a 16 meg
cache and an otherwise identical drive with a 2 meg cache?

With PATA and two drives per channel, it's possible for both drives
together
to fill a 150 MB/sec channel but SATA allows only one per channel so
that's
not an issue.

In any case, some use a bridge chip, others don't. IIRC Seagate is not
using a bridge chip. I don't recall what WD is doing, but their Raptors
outperform any SATA drive from any other manufacturer, although the
Hitachi
7K250 and 7K400 come close, so whether they're using a bridge chip or not
clearly doesn't make any real-world difference.

The Raptors have a bridge chip too. They are basically SCSI drives with
an adapter chip on them.

I see. So you are claiming that they have a SCSI interface bridged to SATA?
Or are you just saying that being constructed to the same quality standards
as server-grade drives somehow makes them have a different interface?

Chip

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

Thanks. I realize they could never hit 150Mb sustained, but is it possible for
150Mb burst with those sata connections on the NF7-S?
If you have a drive even if in the future that is capable of 150Mbs burst speed
can the NF7-S connections support that speed?

where the
caching algorithms have a better chance because of the big files). 16MB
bursting at 150MB/s is not insigificant.

Do the NF7-S sata connections support 150Mb burst speed?

where the
caching algorithms have a better chance because of the big files). 16MB
bursting at 150MB/s is not insigificant.

Do the NF7-S sata connections support 150Mb burst speed?

They are on the PCI buss,so what do you think?