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From: David Empson on 26 Jan 2010 21:22 Erik Richard S�rensen <NOSPAM(a)NOSPAM.dk> wrote: > David Empson wrote: > > Erik Richard S�rensen <NOSPAM(a)NOSPAM.dk> wrote: > >> nospam wrote: > >>> Erik Richard S�rensen <NOSPAM(a)NOSPAM.dk> wrote: > >>>>>> Sure it is. And sure it matters how many UsB devices you connect. > >>>>>> It is obviously that you've never tried running with more than 1-2 > >>>>>> maybe three USB external devices at a time. > >>>>> i have 7 usb devices on my desktop mac. > >>>> Connected how? I guess not individually - rather by hubs... > >>> actually, i miscounted. there are 4 ports on the mac, one of which > >>> feeds a 4 port hub, for a total of 7 ports, all of which are in use. > >>> however, i forgot about the mouse and printer which are plugged into > >>> the keyboard, for a total of 9 devices using two hubs. i have a 7 port > >>> hub to replace the 4 port hub, so i have a couple of spare ports, but > >>> i've managed without, at least so far. > >>> > >>>> And you don�'t have any slow down in speed when > >>>> transferring to/from multi-disks? > >>> nope. > >> This sounds real strange to me. - 7 or 9 devices here doesn't matter... > >> And even more strange that you have connected both printer and mouse to > >> the keyboard. I don't know which keyboard you're using, but an Apple > >> keyboard can only deliever 500mAh, and many printers require the full > >> 800mAh connection. > > > > Where did you get this 800 mA figure from? (Not mAh by the way - that's > > a power rating, not current.) > > From the specs info on the Belkin PCIe USB card and the Belkin UsB hub > I have. Here it's stated 500-800mA. And as I read the info on my MacPro > it also says up to 800mA. Which must be an extension to and not in compliance with USB standards. > > The USB standard allows a maximum current of 500 mA, and the USB > > keyboard is a self-powered hub, which cannot supply more than 100 mA to > > attached devices. > > > > (There have been rumours that Apple's recent USB keyboards and some Mac > > models are able to exceed the 500 mA limit for a USB port on the > > computer for recognised Apple peripherals, and provide up to 500 mA via > > one port on the keyboard, but I haven't seen anything definitive to > > confirm that.) > > At least then I can say that the Intel QuadCore technology claims up to > 800mA on the onboard as well as the Belkin PCIe USB card. - And the same > does my MDD 1,25ghz on a PowerLogix PowerForce Combo USB+FW PCI card > when reading the info in System Profiler (10.4.11+10.5.8) Is that a per-port rating, or maximum total current which can be output by the card, shared between all ports? There will be a limit based on how much current can be sourced via the PCI slot (less whatever the card itself uses). There is a similar issue with several 7-port USB hubs I looked at recently. For the ones which included a power supply and actually documented the rating of that power supply, its maximum output current was not sufficient to supply 500 mA to all ports on the hub (which would require at least 3.5 A). > > Almost all printers have their own power supply and mains cable, so they > > shouldn't need to draw significant power from USB. Some need 500 mA from > > USB for no obvious reason other than lazy design. 100 mA should be > > sufficient. > > Why then the HP dialog? Because that particular printer is one of the ones with lazy design which requires 500 mA from the USB port, despite having its own power supply. Alternatively, its driver may have been deliberately rejecting a printer which was connected anywhere other than a built-in port. There are other USB printers which only require 100 mA from the USB port, and they work fine plugged into the keyboard. > - And I can add here that some years ago with the AGFA SnapScan 1212U and > 1236U scanners, Agfa simply told in the setup guide that connecting to the > hub in the Apple USB keyboards will result in the scanner won't work. Probably because the scanner needed more than 100 mA via USB. > I've also had other printers from HP telling the same in the setup > guidelines. Some even told that I '...must use the built-in USB > connection' - and '...Do not use a PCI USB card for connecting this unit' > (HP white paperes). That could be all sorts of issues, including badly written driver software not being able to support anything other than built-in USB ports. There should be no performance reason to reject a USB PCI card. In older Mac models, the available bandwidth between the CPU and that card would have been exactly the same as for the built-in USB ports, because the PCI bus was used internally to connect the built-in I/O controller to the memory controller. There are performance reasons to reject the use of a USB hub (including the one in the keyboard). A USB hub adds a delay to data transfers because each packet must be buffered and retransmitted. This should only be significant for performance-critical devices. Older Apple keyboards could also be rejected as a connection method because they were only a USB 1.1 hub, not a USB 2.0 hub. If the device requires high speed (only available with USB 2.0) it cannot be used via USB 1.1 hub. > >>>> - If you claim that it is a veeeery special Mac you're > >>>> using. I can guarantee you one thing and that /is/ that the speed is > >>>> slowed down. I have only 3 USB devices connected, keyboard, trackball > >>>> and scanner. And it's for sure that the speed is slowed down when the > >>>> scanner is working at the same time as typing in a document! > >>> scanning slows down when you type? > >> No, typing is slowed down. - I normally type very fast - apprx. 400 > >> strokes per minute, and when the scanner is working and I'm typing I can > >> type lots of letters before they occour in the document. > > > > I don't believe this would have anything to do with USB communication > > bottlenecks. 400 characters per minute is a tiny fraction of the > > potential throughput of USB (even at its slowest 1.5 Mbps). It is more > > likely that something on the computer is being tied up while it is > > processing the scanned data. > > Could be, but why did it then stop, when I moved the scanner to an > internal UsB port? - That makes no sense... So you got slowed typing when the scanner was connected to the USB keyboard? That could be due to it hogging the USB bandwidth on that particular bus, especially if it was an older keyboard which was USB 1.1 only. > > If the computer is old/slow enough, it could be CPU utiltisation due to > > the combination of managing the heavy USB traffic from the scanner plus > > processing the data as it arrives. > > I wouldn't call a MacPro QuaCore 2,66ghz/9gb RAM an 'old an slow' Mac.:-) Ah, I misunderstood based on other things you mentioned. I agree - no CPU issues there, especially as mutliple cores would be free to keep working while one was tied up with USB management and/or data processor. > >>>>> which usb hard drive has both types of ports? > >>>> The French brand, Archos, some of the Mercury enclosures from OWC and > >>>> some of the Weiland professional series enclosures. > >>> which ones, specifically? > >>> > >>> i have a few owc enclosures and none have *both* types of usb ports. > >>> they generally have a mix of usb, firewire 400, firewire 800 and/or > >>> esata, but i've yet to see a hard drive with both a type a & b usb > >>> port. the only way that can occur is if it's *also* a hub, and that > >>> would be unusual for a basic enclosure. > >> You want me to look up each and every model? > > > > How about a link to a single example? > > > >> Nope mi friend! But have a look at the pro series from both Weiland and > >> Mercury... - And else I'll say keep away from the Archos enclosures, - > >> they are real poor and unstable... > > > > The OWC Mercury Elite-AL Pro series do NOT have a piggyback USB type A > > socket. > > > > <http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW > > 400_USB> > > > > (There is a picture of the simpler FW400+USB model on the same page.) > > > > This series does, and it specifically states that it has a built-in USB > > hub. "Mercury Elite-AL Pro Dual-Drive USB 2.0 + USB 2.0 Powered Hub" > > > > <http://eshop.macsales.com/shop/usb2/EliteAL/Pro_USB2_hard_drive_with_Hub> > > 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. > 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. System Profiler would prove the point - it shows the structure of USB hubs and connected peripherals. -- David Empson dempson(a)actrix.gen.nz
From: Erik Richard Sørensen on 27 Jan 2010 07:21 David Empson wrote: > Erik Richard Sørensen <NOSPAM(a)NOSPAM.dk> wrote: >> David Empson wrote: >>> Erik Richard Sørensen <NOSPAM(a)NOSPAM.dk> wrote: >>>> This sounds real strange to me. - 7 or 9 devices here doesn't matter... >>>> And even more strange that you have connected both printer and mouse to >>>> the keyboard. I don't know which keyboard you're using, but an Apple >>>> keyboard can only deliever 500mAh, and many printers require the full >>>> 800mAh connection. >>> Where did you get this 800 mA figure from? (Not mAh by the way - that's >>> a power rating, not current.) >> From the specs info on the Belkin PCIe USB card and the Belkin UsB hub >> I have. Here it's stated 500-800mA. And as I read the info on my MacPro >> it also says up to 800mA. > > Which must be an extension to and not in compliance with USB standards. Could very well be... One of my friends had a HP 3,2ghz Core2Duo, which had some problems with the UsB handling, so he switched to Firewire and he is one of the (few) PC users I know who do swear to FW..-) - When he last year switched to a HP QuadCore 2,4ghz the USB ports now work better - also with devices that earlier required their own PSU now can be pluged and played without any PSU. - But he still prefers FW.:-) >>> The USB standard allows a maximum current of 500 mA, and the USB >>> keyboard is a self-powered hub, which cannot supply more than 100 mA to >>> attached devices. >>> >>> (There have been rumours that Apple's recent USB keyboards and some Mac >>> models are able to exceed the 500 mA limit for a USB port on the >>> computer for recognised Apple peripherals, and provide up to 500 mA via >>> one port on the keyboard, but I haven't seen anything definitive to >>> confirm that.) >> At least then I can say that the Intel QuadCore technology claims up to >> 800mA on the onboard as well as the Belkin PCIe USB card. - And the same >> does my MDD 1,25ghz on a PowerLogix PowerForce Combo USB+FW PCI card >> when reading the info in System Profiler (10.4.11+10.5.8) > > Is that a per-port rating, or maximum total current which can be output > by the card, shared between all ports? There will be a limit based on > how much current can be sourced via the PCI slot (less whatever the card > itself uses). I'm sure that the Belkin PCIe is per-port. And also the PowerForce Combo on the MDD. But here I also can say that I had a QuickSilver - also with a PowerForce Combo. In the QS (10.5.8) the system profiler claimed only up to 500mA per port. Unfortunately PowerLogix no longer makes this card. It's the best card I've ever had [still have two.:-)] - no problems with sleep on the G4s... - It might have been worth testing the PFCombo on an Intel based PC to see, if it also calims up to the 800mA there... Since it looks as if different technology gives different results. > There is a similar issue with several 7-port USB hubs I looked at > recently. For the ones which included a power supply and actually > documented the rating of that power supply, its maximum output current > was not sufficient to supply 500 mA to all ports on the hub (which would > require at least 3.5 A). If I remember right the 7-port Belkin hub I have can give up to 4,2A. - Probably because each port is individually powered. - On the box is stated '...With individually balanced and powered connectors...' - This Belkin hub is USB 2.0HS only. - For my one MDD I have a 4-port noname USB hub, where the PSU claims up to 2,2A. This one is used with the LS-120, LaCie FDD and my one Iomega Zip drive. - I've once tried to use both the PDD along with a Zip - that I donot do anymore. - Transfer speed on the Zip went down to apprxl. 3,2kbps.:-) - I was in a process of transfering all my old floppydisks and would save them on zips, but gave up and just copied to the HD instead... So obivously both hubs and PCI cards can behave different due to use on different hardware technology... >>> Almost all printers have their own power supply and mains cable, so they >>> shouldn't need to draw significant power from USB. Some need 500 mA from >>> USB for no obvious reason other than lazy design. 100 mA should be >>> sufficient. >> Why then the HP dialog? > > Because that particular printer is one of the ones with lazy design > which requires 500 mA from the USB port, despite having its own power > supply. Alternatively, its driver may have been deliberately rejecting a > printer which was connected anywhere other than a built-in port. Could be... - The CDJ-5740 was indeed very fast when it was on it's own..-) - up to 16 ppm text only... > 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... >> - And I can add here that some years ago with the AGFA SnapScan 1212U and >> 1236U scanners, Agfa simply told in the setup guide that connecting to the >> hub in the Apple USB keyboards will result in the scanner won't work. > > Probably because the scanner needed more than 100 mA via USB. Yes, I've just checked the guide - '...requires at least 500mA USB 2.0 only connection...'. Btw. the USB plug is a strange 'double' connector, where two cables - the data cable + the power cable - end up into the same USB plug. - Disconnecting the PSU cable still lets the scanner work on the MacPro but not on the Dual MDD with a MacAlly PCI USB card. This old MacAlly card isn't with individually balanced ports... >> I've also had other printers from HP telling the same in the setup >> guidelines. Some even told that I '...must use the built-in USB >> connection' - and '...Do not use a PCI USB card for connecting this unit' >> (HP white paperes). > > That could be all sorts of issues, including badly written driver > software not being able to support anything other than built-in USB > ports. > > There should be no performance reason to reject a USB PCI card. In older > Mac models, the available bandwidth between the CPU and that card would > have been exactly the same as for the built-in USB ports, because the > PCI bus was used internally to connect the built-in I/O controller to > the memory controller. The problems only came on an old Beige G3/300mhzAV, but after upgrading this one to an 1133mhz G3 the problem disappeared. Also connecting the same printer (PSC-1710) to a PM 9600/350mhz on a PCI USB card gave problems on the PCI BUS'es 2-5 (64bits/33mhz), but moving it to the PCI slot 1 (32bit/66mhz) made it work nicely and fast. The 9600/350 LL/A (European model)( is the only one with both a 33mhz and 66mhz PCI slot. > There are performance reasons to reject the use of a USB hub (including > the one in the keyboard). A USB hub adds a delay to data transfers > because each packet must be buffered and retransmitted. This should only > be significant for performance-critical devices. > > Older Apple keyboards could also be rejected as a connection method > because they were only a USB 1.1 hub, not a USB 2.0 hub. If the device > requires high speed (only available with USB 2.0) it cannot be used via > USB 1.1 hub. As long as it was possible due to system I used the old Apple Extended II ISO keyboard connected with a Griffin iMate. But this combination don't work on an IntelMac. So I bought some used black/silver Apple Pro keyboards as an 'improvised solution' until I could find a just as good a keyboard as the old ISO. I ended up with a Microsoft prof media keyboard with lots of extra function keys - but still only the next-best solution... I know that the Apple Pro keyboards are USB 1.1 only, so that might be one of the reasons that it gave problems with at least two of the HPs... >>>>>> - If you claim that it is a veeeery special Mac you're >>>>>> using. I can guarantee you one thing and that /is/ that the speed is >>>>>> slowed down. I have only 3 USB devices connected, keyboard, trackball >>>>>> and scanner. And it's for sure that the speed is slowed down when the >>>>>> scanner is working at the same time as typing in a document! >>>>> scanning slows down when you type? >>>> No, typing is slowed down. - I normally type very fast - apprx. 400 >>>> strokes per minute, and when the scanner is working and I'm typing I can >>>> type lots of letters before they occour in the document. >>> I don't believe this would have anything to do with USB communication >>> bottlenecks. 400 characters per minute is a tiny fraction of the >>> potential throughput of USB (even at its slowest 1.5 Mbps). It is more >>> likely that something on the computer is being tied up while it is >>> processing the scanned data. >> Could be, but why did it then stop, when I moved the scanner to an >> internal UsB port? - That makes no sense... > > So you got slowed typing when the scanner was connected to the USB > keyboard? That could be due to it hogging the USB bandwidth on that > particular bus, especially if it was an older keyboard which was USB 1.1 > only. Yes, it was the Apple Pro keyboard, and as written the HP scanner requires USB 2.0 only connection which I found out afterwards... >>> The OWC Mercury Elite-AL Pro series do NOT have a piggyback USB type A >>> socket. >>> >>> <http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW >>> 400_USB> >>> >>> (There is a picture of the simpler FW400+USB model on the same page.) >>> >>> This series does, and it specifically states that it has a built-in USB >>> hub. "Mercury Elite-AL Pro Dual-Drive USB 2.0 + USB 2.0 Powered Hub" >>> >>> <http://eshop.macsales.com/shop/usb2/EliteAL/Pro_USB2_hard_drive_with_Hub> >> 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. It has 2x FW 400 + 2x USB, and it was only to tyry 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... >> 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... > 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... - I can't say that it was because of these extras I bought the V3s, 'cause I simpley did not know that it was capable of doing that much.... 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: Warren Oates on 27 Jan 2010 08:11 In article <260120101854185087%nospam(a)nospam.invalid>, nospam <nospam(a)nospam.invalid> wrote: > nope. the usb spec states that 500ma is the maximum, but it's actually > lower than that for a bus-powered hub, such as the one in a keyboard. > furthermore, my printer also plugs into the wall and gets more than > enough power from there so it doesn't need any power from the usb port. Hmm. Your keyboard is on the lower speed bus, though, no? Does your printer work at it's fastest? (No, I don't necessarily know what I'm talking about, but the data rate from the keyboard to the computer is USB1, no?) -- Very old woody beets will never cook tender. -- Fannie Farmer
From: Greg Buchner on 27 Jan 2010 09:23 In article <1jcxsr4.1242oys263itcN%mikePOST(a)TOGROUPmacconsult.com>, mikePOST(a)TOGROUPmacconsult.com (Mike Rosenberg) wrote: > Erik Richard S�rensen <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 Greg B. -- Actual e-mail address is gregbuchner and I'm located at gmail.com
From: David Empson on 27 Jan 2010 09:28
Erik Richard S�rensen <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. 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.) > >>> The OWC Mercury Elite-AL Pro series do NOT have a piggyback USB type A > >>> socket. > >>> > >>> <http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW > >>> 400_USB> > >>> > >>> (There is a picture of the simpler FW400+USB model on the same page.) > >>> > >>> This series does, and it specifically states that it has a built-in USB > >>> hub. "Mercury Elite-AL Pro Dual-Drive USB 2.0 + USB 2.0 Powered Hub" > >>> > >>> <http://eshop.macsales.com/shop/usb2/EliteAL/Pro_USB2_hard_drive_with_Hub> > >> 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. > It has 2x FW 400 + 2x USB, and it was only to tyry 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. 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] 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). > >> 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) 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. 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. > > 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. 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. 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. -- David Empson dempson(a)actrix.gen.nz |