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External Hd Questions...


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#1 brillo

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Posted 07 April 2006 - 11:46 PM

300 Gb external HD, Seagate ultra ATA/100, 7200 RPM, 8MB cache, in a ADS USB2 case, both new. HD partitioned approximately 35GB x 1 volume/65GB x 4 volumes. Computer is Dell Inspiron 6000, 2.13 GHz, 1 GB RAM, XP MCE sp2, both HDs NTSF.

Issues: In moving 7 GB (downloaded movie) from internal HD to external HD, external shut down after almost completing transfer at about 8x speed (so about 15 minutes to move 7GB or 17 Mb/s). This was 3rd movie moved in succession. External HD felt warm, not hot, warm. Fan is apparently working fine, I can hear it; however, I have not yet figured out how to monitor it, either temp or fan speed, as I can/do for internal HD and CPU. etc. using Speedfan program.

I'm assuming heat is the problem, that the ADS case/components are getting hot and shutting the thing down. ADS specs say it has a transfer rate up to 480 Mb/sec, I was only moving about 17 Mb/s, so way below (~1/18th) max transfer rate, if I did the math right. BTW, the external HD when doing nothing except running the fan feels warm. So, as I see it, the options are cool down the external HD or slow it down. I would prefer the former.

Question: is the external HD cooling properly? How do I determine that? How do I improve the cooling? ADS case has very small (tiny) openings for air flow and space inside is adequate but tight. But, this is what it was designed for. Can I alter the case somehow? Or is this just a fairly big HD (designed to have a lot of room for airflow) inside of a small, not very well ventilated/cooled space, and is that just how it's going to be with this setup?

Related question: Can I monitor external HD temp and or fan speed? I assume it has sensor(s). Can I / How do I access that info?

Thanks for your prompt response.

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#2 just me

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Posted 08 April 2006 - 12:06 PM

The maximum speed of a USB 2.0 connection is 480 Mbits/sec. and a disk is a lot slower than that. Besides you are reading data from one disk, buffering it and then transferring it to the second disk.

In addition your calculation is not exactly correct.

7 giga bytes = 7516192768 bytes = 60129542144 bits

60129542144 bits / 900 sec. = 66.8 Mbits/sec.

As far as I know disks do not have temperature sensors and are not designed to slow down or shut off if they get too hot like many CPUs are.

#3 brillo

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Posted 08 April 2006 - 10:56 PM

Thanks to just me for responding and for correcting my math. To quote just me, "60129542144 bits / 900 sec. = 66.8 Mbits/sec." I totally forgot, bits vs. Bytes, 8 to 1 ratio. But, that means a tranfer rate of only 8.25 MB/s, even less than I incorrectly reported. Spec's on the ADS case, (the component that I think is the limiting factor here, not the Seagate HD) is a sustained transfer rate up to 35 MB/s, (it's the max. peak/spike transfer rate that is 480MB/s). So it's tranferring data at way less than spec sustained rate for the case.

There must be at least a temp sensor in the case, after all, it did shut down. It's got a lot of electronics and of course the fan in the case and there has to be some kind of sensor to regulate fan speed and/or shut the thing down if it gets too hot, hopefully both temp and fan speed sensors. No sensors and no response (no fan speed modulation and no shut down at high temp) is foolishness, how could they offer a 5 yr parts and labor warranty if the thing is going to melt down??? I have their phone number and address after all, and a lot of people are far more adamant about things working right or the manufacturer making it right (give back the money).

So, the immediate issue here is to get the output from the internal system to slow down enough to transfer 7+/- GB without heating up and shutting down the external HD (actually I think it's the case that shuts down). That brings me to ventilation again. The case has really poor air movement I think. The openings at the top are tiny slits. There has to be a way to get/keep this thing cooler with the fan obviously trying its best to do the job.

Who among the readers/members here knows how to modify this case physically (my preference) or in the programming to reduce the sustained tranfer rate so it won't heat up and shut down??? (I called ADS, they no longer offer tech. support for this product that I bought at a retail store 3 weeks ago!!!!).

Then, the issue is, Can I monitor external HD case temp and or fan speed? Assuming it has sensor(s), can I / How do I access that info? I want to do that because.... I'm a geek, OK?

#4 paulboc

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Posted 14 April 2006 - 01:30 PM

Hi Brillo, I also have installed a Seagate drive in an external case (Dynex) but my case lacks provision for a fan. It apparently depends on convection for cooling! I was concerned about temperature so I used an instant reading cooking thermometer(Taylor model 9842N ~$20 USD) inserted into a 1/8 in. hole I drilled in the top of the case. Works well. I measure temps of ~100-105 Deg. F. I plan to add a fan to reduce the temp. Excessive temp can cause HDs to do strange things.

#5 Enthusiast

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Posted 15 April 2006 - 01:18 AM

If this is what you have it has a fan in the case but makes no mention of sensors:

http://www.adstech.com/products/USBX-888/i...sp?pid=USBX-888

#6 pascor22234

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Posted 16 April 2006 - 01:41 PM

Your external drive case seems to be the victum of "technology creep" where hard drives are getting incredibly large and so use considerably more power than the days when 40GB and 80GB disks were common aftermarket drive sizes. No wonder ADS discontinued tis case ! They know that people who buy external cases are now putting huge drives in them and this case just isn't up to the task anymore.

Anyhow, I would try enlarging the vent holes and/or adding more to the case furthest from the location of the fan. Unless you use the drive on a carpeted rug I wouldn't worry much about dust buildup. You've got to get the airflow moving better, so don't be shy about adding vent holes.

As for monitoring temperatures, I read somewhere that hard drives' S.M.A.R.T. capability was supposed to be able to read temp sensors in a drive but I'v never come across a utility that does this. The temperature sensor that is responsible for shutting down the electronics is probably a fairly simple safeguard circuit and can not be monitored.

Do you know whether its the case electronics thats shutting down or the drive, itself (not that this really matters) ? I would guess that its the drive thats shutting down because modern disk drives are very sophisticated in that they monitor their own supply voltages. Adding a temperature shutdown circuit for the drive electronics is marginally less expensive compared to adding that to an external case's circuitry. External drive circuitry is extremely simple - a bare bones power supply that produces +5V and +12V
and one chip that converts USB signals to and from IDE/ATA.

One more thought - the large software overhead that is required for USB(2) is why you're getting only 67Mbps out of the theoretical maximum of 480. This rate is actually pretty good ! Firewire interfaces are popular because the mechanics of its operation requires less software overhead and so gets a higher actual transfer rates than USB2.

Happy drilling

#7 linderman

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Posted 16 April 2006 - 02:03 PM

Hello:



I know you are probally not going to like my solution; but you will need to abandon that case >>>> your big drive and the size and duration of your file transfers make it a poor choice for your projects,

You should be looking for an external enclosure suitable for a high rpm SATA or SCSI drive (10,000 rpm & 15,000 rpm) more air flow
http://www.addonics.com/products/combo_hdd/aechdsa35.asp

another problem you maybe encountering is your PSU may not be up to that work load >>>> what make and size PSU are you running

as far as hard drive temps go ???? 55C is the manufacturer's stated critical temp >>>> but personally I would not be happy with more than 40C

goodluck

#8 linderman

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Posted 16 April 2006 - 05:26 PM

http://www.performance-pcs.com/catalog/ind...roducts_id=3989



SEE THE AIR CONDITIONER ***********




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