Question about External HD
in [Mac Systems]
|
Prev: X11 startup configurations
Next: Secure Empty Trash
From: Daniel Cohen on 26 Jan 2010 13:07 nospam <nospam(a)nospam.invalid> wrote: > In article <tom_stiller-20B9BE.16072925012010(a)news.individual.net>, Tom > Stiller <tom_stiller(a)yahoo.com> wrote: > > > FireWire hubs exist also. > > true, but rarely used. they're also not required for multiple devices, > whereas a usb hub is. Does daisy-chaiming FireWire devices work if intermediate devices are swtiched off? My impression was that it didn't, which provides a reason for using a hub. -- <http://www.decohen.com> Send e-mail to the Reply-To address. Mail to the From address is never read.
From: nospam on 26 Jan 2010 13:57 In article <1jcxfgf.1ri84xl23h34N%dcohenspam(a)talktalk.net>, Daniel Cohen <dcohenspam(a)talktalk.net> wrote: > Does daisy-chaiming FireWire devices work if intermediate devices are > swtiched off? technically it should. a device that doesn't is not fully compliant. unfortunately, there's a lot of those out there.
From: Erik Richard Sørensen on 26 Jan 2010 17:06 nospam wrote: > Erik Richard Sørensen <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 donø'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. - I had a HP Color DeskJet 5740, which I at first connected to the black/silver Apple Pro keyboard on my MacPro, but the first time I used it, a dialog told me that the printer was unavailable though the System profiler could see the printer and it was visible in the 'Printer&Fax controlpane. - As soon as I got beneith and behind the MacPro with the cable, the printer began to print from the cue... - Also my trackball works best on a separate port instead of connecting it to a keyboard. - And now since I've bought a professional Microsoft keyboard it isn't possible to connect anything to the keyboard... >> - 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 know others who have the same problem on more different newer Mac models like G5s and MacPros. >>> from the developer note for the ibook dual usb: >>> >>> <http://developer.apple.com/legacy/mac/library/documentation/Hardware/De >>> veloper_Notes/Macintosh_CPUs-G3/ibook08May01/ibook-17.html#25515> >>> >>> The Pangea IC implements two independent USB controllers (root hubs), >>> each of which is connected to one of the ports on the back panel of >>> the computer. The use of two independent controllers allows both USB >>> ports to support high data rate devices at the same time with no >>> degradation of their performance. If a user connects a high-speed >>> (12 Mbps) device to one port and another high-speed device to the >>> other, both devices can operate at their full data rates. >>> >>> read that last sentence a couple of times. >> Yeah and? - Here's explecitely mentioned _two_USB_controllers_ not _one_ >> controller with independant circuits or one controller with dual or >> triple circuitry which is the normal on most common PCs. > > this is about macs, not 'most common pcs.' You could say that before Apple switched to the Intel technology, but now the hardware are more like common PCs. >> But even when there are those two controllers, you will experience some >> slow down in speed, since both controllers are relying on the same CPU. >> But it's also true that the slow down will be smaller in this construction. > > what part of USB requires quite a lot more CPU power than Firewire... > "The use of two independent controllers allows both USB ports to > support high data rate devices at the same time with no degradation of > their performance. " > > is not clear? > > note the where it says, 'no degradation of performance'. Theoretically yes, but practically no! >>> 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? 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... >>> i've never seen a drive that can use both usb *and* firewire at the >>> same time. some even have physical switches, although most auto-detect. >>> which usb drive is this? >> Enclosures from NewerTech. > > the newertech ministack includes a usb and firewire hub (two separate > hubs for two separate connections), as well as a hard drive. is that > what you are thinking of? I'm talking about that I can use the USB ports even if the MiniStacks are connected through FW400/800, but it of course requires that the power is turned ON. 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 26 Jan 2010 17:10 Daniel Cohen wrote: > nospam <nospam(a)nospam.invalid> wrote: >> Tom Stiller <tom_stiller(a)yahoo.com> wrote: >>> FireWire hubs exist also. >> true, but rarely used. they're also not required for multiple devices, >> whereas a usb hub is. > > Does daisy-chaiming FireWire devices work if intermediate devices are > swtiched off? > > My impression was that it didn't, which provides a reason for using a > hub. You're right about that all unit must be powered on, if for example the last one in the chain is to be used. That's also 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: Mike Rosenberg on 26 Jan 2010 17:34
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. -- 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> |