Question about External HD
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From: Erik Richard Sørensen on 27 Jan 2010 11:23 Greg Buchner wrote: > Mike Rosenberg wrote: >> Erik Richard Sørensen <NOSPAM(a)NOSPAM.dk> wrote: >>> You're right about that all unit must be powered on, if for example the >>> last one in the chain is to be used. >> No, this is not true, not if all the units conform to specifications. > > Correct. I have one FW case that allows for pass-through. It's nice not > having to turn that case on just to get to my DVD burner. > > http://www.newegg.com/Product/Product.aspx?Item=N82E16817347017 Hm, I have 11 external Firewire units of various brands - Mercury, Formac, LaCie d2, LaCie Pro P5... _All_ of them require the unit in front of the actual unit to be powered on before the actual unit can be used, if they are daisy-chained. - That's why I bought the Belkin FW hub... Cheers, Erik Richard -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Erik Richard Sørensen, Member of ADC, <mac-manNOSP(a)Mstofanet.dk> NisusWriter - The Future In Multilingual Text Processing - www.nisus.com OpenOffice.org - The Modern Productivity Solution - www.openoffice.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: Erik Richard Sørensen on 27 Jan 2010 12:21 David Empson wrote: > Erik Richard Sørensen <NOSPAM(a)NOSPAM.dk> wrote: > >> David Empson wrote: >>> There are other USB printers which only require 100 mA from the USB >>> port, and they work fine plugged into the keyboard. >> Maybe I've then just been unlucky with my choices in printers. None of >> those I've had would run through the black/Usilver Apple Pro keybaord... > > That particular keyboard only has USB 1.1, so it could also be > incompatible with a printer that needs USB 2.0. Yes, but the HP PSC-1110 also was USB 1.1. > The aluminium USB keyboards are definitely USB 2.0, but I'm pretty sure > the white "Apple Keyboard" which preceded it is also USB 1.1. (Don't > have one to check.) Yes, I had one, but I don't like it, so I sold it along with the Apple Pro mouse. >>>> I didn't mention anything about connector types on the Mercury Pro >>>> series, neither on the MiniStacks. >>> You were claiming that some USB hard drives could "daisy chain" USB. >>> nospam's point (which I agree with) is that they can only do this is if >>> they have a built-in USB hub. >> It was nowhere written that this enclosure had a built-in hub. > > Just because they didn't explain it doesn't mean anything. Right, but it's neither pro nor contra... Nothing like 'USB hub' was mentioned neither in white-papers nor electronically...... >> It has 2x FW 400 + 2x USB, and it was only to try it I connected it via >> USB and then plugged in an UsB card reader into the other USB port - and >> sure both showed up on the desktop... > > If you were able to plug the drive into the computer via one USB port > and a USB card reader into the other USB port, they must have been > different types of USB port. USB has different connectors for "upstream" > and "downstream" directions. Could be, I don't recall which USB connectors. But I connected it via _Firewire_ and added the UsB stick (a Trust Minireader). > The only way it is possible to "daisy chain" USB is if the device which > presents another USB port has implemented an internal USB hub, and its > own functionality is a device attached to that hub. The USB connection > from a single port on the computer can only go to a single device: > either a peripheral which is the end of the chain, or a hub which can > can then supply connections to two or more devices. > > As I alluded to in my previous post, you can use System Profiler to > establish how the USB devices are arranged. Each hub appears as an > additional layer in the device tree. I expect you would see something > like this with the arrangement you described above: > > USB High-speed Bus [built into the computer] > | > +--- Hub [in the enclosure] > | > +--- Hard drive [in the enclosure] > | > +--- USB card reader [piggybacked from the enclosure] Very good illustrated. And when the enclosure was connected via FW400 and turned on and adding the card reader made a new branch on that tree. > So far I have yet to see any evidence of this supposed Mercury Elite > with two USB ports. > > The only hard drive enclosures I spotted on OWC at the moment with > multiple USB ports are the NewerTech MiniStack (with a USB hub including > several type A ports and one type B port), and a Mercury Elite-Al Pro > dual drive with built-in USB hub (with three USB type A ports plus one > type B port). As written - this enclosure is now discontinued in favor of both the MiniStacks and the AL Pro series. >>>> A fact is that I've connected both a MiniStack V3 and a Mercury Elite Pro >>>> USB2.0HS/FW400 (not the AL Pro) in daisy-chained FW and then added an UsB >>>> stick to the Mercury. The USB stick showed fast and nicely up on the >>>> desktop. Afterwards I tried the same with the V3, and again the stick >>>> showed up on the desktop. >>> You must have also had USB connected to the computer for that to work. >> Nope... > > So you are claiming that you had a connection like this? > > Computer ---FW--- MiniStack ---FW--- Mercury ---USB--- card reader > > (with no other USB connections) Exactly. > That seems highly unlikely. It would require the Mercury Elite to > implement a USB host with support for mass storage peripherals, which is > then mapped to appear as a Firewire peripheral as far as the computer is > concerned. Seems like an awful lot of extra functionality to save you > the trouble of plugging in a single USB cable. Maybe, but useful if you don't have too many free USB connections. > You then claim you did this? > > Computer ---FW--- MiniStack --- USB--- card reader > > (with no USB connection between the MiniStack and computer) > > That is impossible. The MiniStack's manual says that its USB hub > requires the USB uplink port to be connected to the computer. (Same with > its Firewire hub.) > > If you actually had the USB cable AND Firewire cable between the > computer and MiniStack then it will work fine. OK, I may have expressed myself a bit unclear here. It was only possible with the Mercury and NOT the MiniStack V3. I.e. only this combination Computer ---FW--- MiniStack ---FW--- Mercury ---USB--- card reader >>> System Profiler would prove the point - it shows the structure of USB >>> hubs and connected peripherals. >> Yep... As soon as I turn on the V3 the extra FW and USB connectors also >> occour in the System Profiler as well as the eSATA connection... > > The eSATA port on the MiniStack is one of the options for connecting the > MiniStack to the computer (assuming you have an eSATA port on the > computer), for maximum speed of connection to its internal hard drive > only. I don't use eSATA since I have no eSATA PCIe card on the MacPro. > If you had the MiniStack plugged in via USB and Firewire but not eSATA, > its eSATA port would be dormant and would not appear in System Profiler. The System Profiler shows an eSATA connection, but since I donot have anyh eSATA card, it can only be from the MiniStack... I didnot say that I use(d) it! > If you had the MiniStack plugged in only via eSATA you could use its > internal drive but its Firewire and USB hubs would be dormant and would > not appear in System Profiler. This I don't know anything about since I have no eSATA card... Cheers, Erik Richard -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Erik Richard Sørensen, Member of ADC, <mac-manNOSP(a)Mstofanet.dk> NisusWriter - The Future In Multilingual Text Processing - www.nisus.com OpenOffice.org - The Modern Productivity Solution - www.openoffice.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: Mike Rosenberg on 27 Jan 2010 16:35
Erik Richard S�rensen <NOSPAM(a)NOSPAM.dk> wrote: > Hm, I have 11 external Firewire units of various brands - Mercury, > Formac, LaCie d2, LaCie Pro P5... _All_ of them require the unit in > front of the actual unit to be powered on before the actual unit can be > used, if they are daisy-chained. Well, once again your experiences are different than most everyone else's. I routine daisy chain my external drives to FW devices already connected to a client's Mac and only rarely do I have to power up any of those devices. -- My latest dance performance <http://www.youtube.com/watch?v=I_9pudbFisE> Mac and geek T-shirts & gifts <http://designsbymike.net/shop/mac.cgi> Prius shirts/bumper stickers <http://designsbymike.net/shop/prius.cgi> |