Portable USB 2.0 1TB drive that is FAST

[Frank Williams]

Need for a PVR box, I would like the drive to be USB powered, I tested
my WD Elements 500Gb and that were not much faster than a Fast USB
stick, using CrystalDiskMark.


Transent Jetflash 110 2GB.

http://www.transcendusa.com/products/ModDetail.asp?ModNo=68&LangNo=0&Func1No=&Func2No=

Are Seagate ones any faster.?

 

[Rod Speed]

Need for a PVR box, I would like the drive to be USB powered,
I tested my WD Elements 500Gb and that were not much
faster than a Fast USB stick, using CrystalDiskMark.

Transent Jetflash 110 2GB.

Are Seagate ones any faster.?

Why do you believe you need a FAST drive ?

My PVR can record 4 channels simultaneously and works fine with 5400 RPM green drives.

It isnt even working hard and I can play recorded stuff from the
drive and do mass file copying while the capturing is going on fine.

 

[Frank Williams]

Why do you believe you need a FAST drive ?

My PVR can record 4 channels simultaneously and works fine with 5400 RPM green drives.

It isnt even working hard and I can play recorded stuff from the
drive and do mass file copying while the capturing is going on fine.

I am referring to a Portable USB powered HD.

Also I am referring to Full HD recordings, 1080P raw bit stream.


Plus many comments in Forums about drives for this PVR box and refereed
to a Web site that listed preferred drives but that site is down for
maintenance.

What Model is your PVR or is it a Computer setup.

 

[Rod Speed]

Frank Williams wrote

I am referring to a Portable USB powered HD.

Sure, but that doesnt affect the speed you need.

Also I am referring to Full HD recordings, 1080P raw bit stream.

Sure, so am I.

Plus many comments in Forums about drives for
this PVR box and refereed to a Web site that listed
preferred drives but that site is down for maintenance.

What Model is your PVR or is it a Computer setup.

Yes, its a computer setup. But the speed of the drive needed is
determined by the bit rate of what is streamed to disk, so the
same considerations apply.

 

[Tom Del Rosso]

My PVR can record 4 channels simultaneously and works fine with 5400
RPM green drives.

Is that a satellite card? My signal comes from a cable box, so I'm
limited to 1 channel.

 

[Rod Speed]

Tom Del Rosso wrote

Rod Speed wrote

Is that a satellite card?
Nope.

My signal comes from a cable box, so I'm limited to 1 channel.

Mine is free to air TV and that 4 channels is 4 of the TV transmitter channels, with as many
of the digital channels multiplexed onto the TV transmitter channels as are broadcast.

 

[Frank Williams]

Frank Williams wrote


Sure, but that doesnt affect the speed you need.


Sure, so am I.



Yes, its a computer setup. But the speed of the drive needed is
determined by the bit rate of what is streamed to disk, so the
same considerations apply.

The WD Elements 500Gb I tested gave these results

CrystalDiskMark 100Mb file size one pass only.

Seg R18,84 W 16,2

512K 12.94 17.37

4K o,328 0.619

4k QD32 0.385 0.604

All MBs

Transend fast USB stick

Seg R16.81 W11.66

512K 16.88 8.54

4K 2.086 0.498

4K QD32 2.312 0.338


Seq : Sequential Read/Write Test (Block Size = 1024KB)
512K : Random Read/Write Test (Block Size = 512KB)
4K : Random Read/Write Test (Block Size = 4KB)
4K QD32 : Random Read/Write Test (Block Size = 4KB, Queue Depth = 32)
for NCQ&AHCI

WD green drives, I have one of these and they are a 2 speed drive.


Also the burst data rate will be way faster for a 3.5" drive than a
2.5" plus the seek rate..?

WD does not list any data on this or even the spindle speed.

 

[Franc Zabkar]

Need for a PVR box, I would like the drive to be USB powered, I tested
my WD Elements 500Gb and that were not much faster than a Fast USB
stick, using CrystalDiskMark.


Transent Jetflash 110 2GB.

http://www.transcendusa.com/products/ModDetail.asp?ModNo=68&LangNo=0&Func1No=&Func2No=

Are Seagate ones any faster.?

USB 2.0 drives are throttled by the USB interface. They typically
achieve transfer rates of around 20MB/s, perhaps as high as 30MB/s.

IMHO you would be better off choosing a 5400 RPM drive for temperature
and noise reasons.

- Franc Zabkar

 

[Franc Zabkar]

WD green drives, I have one of these and they are a 2 speed drive.

No they are not. WD's IntelliPower is just confusing marketingspeak.
The drives actually rotate at a fixed speed of 5400 RPM.

In fact, buried within the IntelliPower obfuscation is this statement
from WD:

"For each drive model, WD may use a different, invariable RPM."

AIUI, a drive's heads fly on an air bearing generated by the spinning
platters. If the rotation speed were to vary, then so would the flying
height, leading to variations in read/write amplitude. Therefore the
heads are aerodynamically tuned to a particular speed, and that speed
is tightly controlled.

See this article where the RPM is actaully measured using a sound
card, a microphone, and Fourier analysis software:

http://www.silentpcreview.com/article786-page2.html

You can also use HD Tune to "measure" the RPM:
http://groups.google.com/group/comp...77f6c190f35/0f5a4c36d4afc140#0f5a4c36d4afc140

- Franc Zabkar

 

[Frank Williams]

USB 2.0 drives are throttled by the USB interface. They typically
achieve transfer rates of around 20MB/s, perhaps as high as 30MB/s.

I don't think so as USB 2 is rated at some 480Mbs that's a 60MBs speed.


I think the drives suffer due to low spindle speed, platter size and
seek rate.

The seek time is the killer for all hard drives and the self powered
ones will also be slow to fit in with the 0.5amp USB power requirements.

 

[Franc Zabkar]

I don't think so as USB 2 is rated at some 480Mbs that's a 60MBs speed.

That's not what is achieved in practice.

Have a look at the reviews. I don't believe there is any USB 2.0 drive
that achieves 30MB/s, let alone 60MB/s.

Your mission, should you choose to accept it, is to find one.

I think the drives suffer due to low spindle speed, platter size and
seek rate.

Higher spindle speeds and higher platter densities will improve the
transfer rate for an internal drive, but will make little, if any,
difference to a USB 2.0 drive.

The seek time is the killer for all hard drives ...

AFAICT, seek time is about the same for all hard drives, unless you go
for the high end enterprise models.

For example, Seagate's 5400 RPM Momentus drives have a full-stroke
seek time of 27ms, whereas their 7200 RPM siblings have a seek time of
22ms.

In any case, if you are transferring a large, contiguous file, eg a
movie, then the sustained transfer rate is the more important
criterion.

... and the self powered
ones will also be slow to fit in with the 0.5amp USB power requirements.

The self powered ones are 2.5" drives.

Seagate's 7200 RPM Momentus drives consume more power than their 5400
RPM siblings, but they still remain within the 500mA limit after
spin-up.

See page 15 of the following document.

Momentus 7200-RPM / 5400-RPM Product Manual:
http://www.seagate.com/staticfiles/...ok/momentus/Momentus 5400_7200/100627937c.pdf

- Franc Zabkar

 

[Tom Del Rosso]

I've had a problem with heat caused by continuous thrashing in some
drives, but it would seem that recording 4 at once would cause less
thrashing than playing 4 at once, albeit with resulting fragmentation.
(Unless NTFS does simultaneous writes with some kind of fragmentation
avoidance, but I don't know of it doing that.)

The RPM isn't really a limiting factor there, so with less heat it's an
advantage.

Mine is free to air TV and that 4 channels is 4 of the TV transmitter
channels, with as many of the digital channels multiplexed onto the
TV transmitter channels as are broadcast.

So you can record 5.1, 5.2, 5.3, and 5.4 at the same time, but not 5.1
and 7.1?

Is that a Hauppauge? Which?

 

[Tom Del Rosso]

Have a look at the reviews. I don't believe there is any USB 2.0 drive
that achieves 30MB/s, let alone 60MB/s.

At almost 2 minutes to copy a 3GB file that seems right in practice.

 

[Frank Williams]

At almost 2 minutes to copy a 3GB file that seems right in practice.

I read some detail articles regarding USB 2 speeds, and it sated nothing
has achieved the 480 Max but in real terms is more like 320Mbs that =
40MBs...


http://www.everythingusb.com/speed.html

 

[Rod Speed]

Frank Williams wrote

I don't think so as USB 2 is rated at some 480Mbs that's a 60MBs speed.

But you dont see anything like 60MB/s in practice.

I think the drives suffer due to low spindle speed, platter size and seek rate.

Nope, they are indeed limited by the USB2 interface.

You get a much faster thruput when you use a eSATA connection with
an external drive that can do both, even with 5400 rpm green drives.

The seek time is the killer for all hard drives

Nope, not with a PVR that doesnt seek much at all. The transfer time is
completely dominated by the speed at which data is streamed to the drive.

and the self powered ones will also be slow to
fit in with the 0.5amp USB power requirements.

That doesnt happen either. The only drives that can be powered from the
USB connection are 2.5" drives, 3.5" drives take more than that when starting.

 

[Tom Del Rosso]

I never play more than one at once deliberately.

Neither do I, but I do the equivalent, which is copy several at once,
sometimes.

I buy quite a few because I watch a lot less than I record.

Same here, though only up to my sixth drive for that purpose.

BTW, I use GBPVR s/w after testing nearly ten others. It's downside is
it has only minute resolution in recording times. Many shows require an
extra 5-10 seconds at the start and end. If I set it for a whole extra
minute it would sometimes miss the start or end of something else. So I
wrote a batch file that offsets the NTP time at preset hours on a daily
or weekly schedule, if you want it. Several months ago I posted it at
alt.msdos.batch.nt but I've made improvements.

I can record 5.1, 5.2, 5.3, 5.4, and 6.1, 6.2, 6.3, 6.4, and 7.1,
7.2, 7.3, 7.4, and 8.1, 8.2, 8.3, 8.4 all at once.

If it's the same data rate as usual for a normal definition signal then
that's only 16MB/sec. But ATSC must be compressed more than that
already, so how many bytes does the card produce per channel per second?

 

[Rod Speed]

Tom Del Rosso wrote

Rod Speed wrote

Same here, though only up to my sixth drive for that purpose.

I'm up to about 10 now, initially 1 TB. then 1.5TB, currently
2TB, because the 3TB drives arent best $/GB yet.

BTW, I use GBPVR s/w after testing nearly ten others.

I use DVB Scheduler Pro, basically because its the only one I
have tried that automatically works out which channels are on
which of the broadcasted TV channels and auto strips out the
individual channels into separate disk files and labels them.

It's downside is it has only minute resolution in recording times.

So is mine, but thats no big deal because I start most recordings
a minute before the scheduled time and pad the end with anything
from 10 mins to 1 hour extra depending on the particular channel
and the time of day with the channels that are the worst for letting
their broadcast time slip grossly.

Many shows require an extra 5-10 seconds at the start and end.

Some of mine end up 30 mins late ocassionally.

If I set it for a whole extra minute it would sometimes miss the start or end of something else.

I never have that problem anymore because I can record everything
broadcast, quite literally, including the TV and digital radio channels
and the EPGs as well.

So I wrote a batch file that offsets the NTP time at preset hours on a daily or weekly schedule,

I use an Access database to decide what I will record and it adds
the extra stuff auto. I do it that way basically because the database
allows me to keep track of what I have already watched with repeats
and allows me to work out what to watch next because it has the full
description of most of the recorded stuff rather than just a title.

It gets all that stuff of the web, from the TV channel web sites and one
of our online TV schedule web sites.

if you want it. Several months ago I posted it at alt.msdos.batch.nt but I've made improvements.

Thanks for the offer.

If it's the same data rate as usual for a normal definition signal

That varys. Some channels are HD and some are SD.

then that's only 16MB/sec. But ATSC must be compressed more than that
already, so how many bytes does the card produce per channel per second?

It varys a bit by channel, but its basically roughly 2GB per channel per hour for SD channels.

 

[Tom Del Rosso]

I use an Access database to decide what I will record and it adds
the extra stuff auto. I do it that way basically because the database
allows me to keep track of what I have already watched with repeats
and allows me to work out what to watch next because it has the full
description of most of the recorded stuff rather than just a title.

It gets all that stuff of the web, from the TV channel web sites and
one of our online TV schedule web sites.

Does DVB integrate with Access, or you built a bridge in software?

 

[Rod Speed]

Tom Del Rosso wrote

Rod Speed wrote

Does DVB integrate with Access,
No.

or you built a bridge in software?

Yes.