Post by thread:[OT] Gadget review: USB to 2.5" hard drive

I recently acquired a 30 gig 2.5" hard drive - out of a laptop in a dumpster. Occasionally needing to transfer more than will fit on a CD from work to home to work, I looked around for ways to use the drive and found this gadget: NexStar external 2.5" hard drive enclosure from http://www.vantecusa.com which runs from USB and also is USB powered. Mine came from Jameco but Vantec sells through other outlets as well. http://jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=453376 The cool deal: at Jameco, $17.45 each. It seemed to me to be a good bargain. They had others up to $70-80 or so. Performance: Win98SE - USB 1.1, about 1MB/s; WinXP - USB 2.0, about 10 times as fast, roughly. It came with a carrying pouch, a CD with Windows-only drivers, and a double headed USB cable. The cable allows drives that require more than 500mA to get up to 1000mA. If you have a drive the needs more than that, there is a DC input jack but no power supply comes with the device. Mine did not work until I figured out which of the 2 usb plugs to use - the second one has power only and no serial wires. If you happen to have a 2.5" hard drive laying around, this might be useful to you.

Recently did the same myself -- resuced the 30Gbyte drive from my beaten up Powerbook. Found a cheap aluminum USB case in my local Chinatown for ~CDN$16. BTW...isn't USB rated for 5watts? i.e. 1A PER port, not 500mA? -marc On 10/27/05, Marcel Duchamp <spam_OUTmarcel.duchampTakeThisOuTsbcglobal.net> wrote: {Quote hidden}> > I recently acquired a 30 gig 2.5" hard drive - out of a laptop in a > dumpster. Occasionally needing to transfer more than will fit on a CD > from work to home to work, I looked around for ways to use the drive and > found this gadget: > > NexStar external 2.5" hard drive enclosure from http://www.vantecusa.com<http://www.vantecusa.com>which > runs from USB and also is USB powered. Mine came from Jameco but Vantec > sells through other outlets as well. > > > http://jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=453376 > > The cool deal: at Jameco, $17.45 each. It seemed to me to be a good > bargain. They had others up to $70-80 or so. > > Performance: > Win98SE - USB 1.1, about 1MB/s; > WinXP - USB 2.0, about 10 times as fast, roughly. > > It came with a carrying pouch, a CD with Windows-only drivers, and a > double headed USB cable. The cable allows drives that require more than > 500mA to get up to 1000mA. If you have a drive the needs more than > that, there is a DC input jack but no power supply comes with the > device. Mine did not work until I figured out which of the 2 usb plugs > to use - the second one has power only and no serial wires. > > If you happen to have a 2.5" hard drive laying around, this might be > useful to you. >

Directly relevant paper www.seagate.com/docs/pdf/whitepaper/TP-535.pdf " The USB 1.1 and 2.0 specification requires that each USB port delivers at least 500 mA of steady-state current; however the majority of systems provide 700 mA of steady-state current. Most 2.5-inch disc drives meet this requirement only after they are already spinning and usually require a higher current during the initial spin-up profile. The majority of USB ports also allows for a higher current draw of 1000 to 1100 mA for a limited duration (instantaneous current) that allows the disc drive to spin up adequately. This capability varies from PC to PC and depends on a variety of factors such as the type of USB port, the USB controller used, the type of regulator and the type of capacitors at the host. " Marc Nicholas wrote: {Quote hidden}> Recently did the same myself -- resuced the 30Gbyte drive from my beaten up > Powerbook. Found a cheap aluminum USB case in my local Chinatown for > ~CDN$16. > > BTW...isn't USB rated for 5watts? i.e. 1A PER port, not 500mA? > > -marc > > On 10/27/05, Marcel Duchamp <.....marcel.duchampKILLspam@spam@sbcglobal.net> wrote: > >>I recently acquired a 30 gig 2.5" hard drive - out of a laptop in a >>dumpster. Occasionally needing to transfer more than will fit on a CD >>from work to home to work, I looked around for ways to use the drive and >>found this gadget: >> >>NexStar external 2.5" hard drive enclosure from http://www.vantecusa.com<http://www.vantecusa.com>which >>runs from USB and also is USB powered. Mine came from Jameco but Vantec >>sells through other outlets as well. >> >> >>jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=453376 >> >>The cool deal: at Jameco, $17.45 each. It seemed to me to be a good >>bargain. They had others up to $70-80 or so. >> >>Performance: >>Win98SE - USB 1.1, about 1MB/s; >>WinXP - USB 2.0, about 10 times as fast, roughly. >> >>It came with a carrying pouch, a CD with Windows-only drivers, and a >>double headed USB cable. The cable allows drives that require more than >>500mA to get up to 1000mA. If you have a drive the needs more than >>that, there is a DC input jack but no power supply comes with the >>device. Mine did not work until I figured out which of the 2 usb plugs >>to use - the second one has power only and no serial wires. >> >>If you happen to have a 2.5" hard drive laying around, this might be >>useful to you. >>-

Robert Rolf wrote: > The USB 1.1 and 2.0 specification requires that each USB port delivers > at least 500 mA of steady-state current; It's been a while since I read that spec, but I recall that each device was guaranteed a minimum of 100mA. A device can ask for more and receive up to 500mA but the controller is not obligated to supply it and the device must behave resonably when it doesn't get it. Many USB host implementations may tie the power line to the +5V supply so you may get what the cable and power supply can bear in many cases, but that is not guaranteed and it's a violation of the USB spec for a device to rely on that. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products

> I recently acquired a 30 gig 2.5" hard drive - out of a laptop in a > dumpster. Occasionally needing to transfer more than will fit on a CD > from work to home to work, I looked around for ways to use the drive and > found this gadget: > > NexStar external 2.5" hard drive enclosure from http://www.vantecusa.com which > runs from USB and also is USB powered. Mine came from Jameco but Vantec > sells through other outlets as well. I've seen similar devices which are just bare cable, with the pertinent (IDE, SATA, drive power) connectors at the opposite end of the USB connector. These are the ones that are TRULY gems for IT workers. If I had $1 for every time I or one of my coworkers took someones drive out of a failed PC, cracked my own case, stuck it in and then started copying data, I'd go to lunch without _any_ remorse today. Probably only at McDonald's, but still... ;-) Mike H.

> The USB 1.1 and 2.0 specification requires that each USB port delivers at > least 500 mA of steady-state current; however the > majority of systems provide 700 mA of steady-state current. Most 2.5-inch > disc drives meet this requirement only after they are > already spinning and usually require a higher current during the initial > spin-up profile. The majority of USB ports also allows for > a higher current draw of 1000 to 1100 mA for a limited duration > (instantaneous current) that allows the disc drive to spin up > adequately. This capability varies from PC to PC and depends on a variety of > factors such as the type of USB port, the USB > controller used, the type of regulator and the type of capacitors at the > host. Which in plain English means (to me) that most external USB hard disks are knowingly manufactured and knowingly to be operated out of spec (for the USB power) (and the reason for thex extra power cord/power connector receptacle - which few users bother to use if they can get away with it - or rather without it). Something I have argued several times over with other people, who kept going back to the irrefutable 'but it works for me' argument (this sometimes under conditions of whether-it-is-under-warranty-or-not discussions). I also wrote some bitter words about the USB 'industry' in the past in this mailing list. That was not a coincidence. It is my understanding that a standard (such as 500mA available *after* negotiation) is a standard and not an elective recommendation. Compare, for example, with the PoE standards which are much more complete (in despite of a lot of leeway in the actually accepted supply voltages of consumer (as in powered load) devices). Peter

> Many USB host implementations may tie the power line to the +5V supply so > you may get what the cable and power supply can bear in many cases, but that > is not guaranteed and it's a violation of the USB spec for a device to rely > on that. You may find that virtually all motherboards which do not use a proper USB power controller for the USB power, use a polyfuse per USB socket and supply it from the 5V board power. The polyfuse will save the board and the peripheral from fire (*many* miswired cables are on sale - esp 'replacement' cables for digital cameras with special connectors on the camera side) but it causes the output to drop to 3.3V or less at full load (500mA). Peter

On Oct 28, 2005, at 1:05 PM, Peter wrote: >> BTW...isn't USB rated for 5watts? i.e. 1A PER port, not 500mA? > > 500mA after negotiation, and often 3.3V instead of 5V under load > with some motherboards. Many USB ports seem to use one of those self-resetting "polyfuse" things as a current limitter. If you've played with these, you know that a 0.5 Amp polyfuse will pass a significantly higher current for 'a while' before it trips open... Apple Macs (powerbooks? maybe all?) are becoming infamous for being unable to power external USB drives from a single "USB 2.0" port. It's not their fault for following the specs, but users are less than pleased. BillW

On Fri, 28 Oct 2005, William Chops Westfield wrote: > Apple Macs (powerbooks? maybe all?) are becoming infamous for being > unable to power external USB drives from a single "USB 2.0" port. It's > not their fault for following the specs, but users are less than pleased. Yes. Once a counterfeit power plug marked '10A fused' that is known not to be fused so anyone can plug in their kettle, people will no longer want the genuine article. At least polyfuses are fireproof. I think that the best strategy at the moment for laptop board makers is to put a power mosfet in series with a polyfuse for each USB female connector and sequence them at power up (so the inrush does not bring down the internal rail). All this because of the lame power specification for the USB bus in the first place. They had to be so very clever. Peter