6 Replies Latest reply: Jan 15, 2007 5:51 PM by motc
motc Level 1 (5 points)
I recently received some helpful advice on this forum concerning formatting an external USB 2.0 hard drive for the Mac. I have a couple related questions concerning USB 2.0 vs 1.1.

I'm using an iBook G3/900MHz/640 MB, originally purchased in 2003, with OS 9.2.2 & 10.2.4 in a dual boot configuration. I pretty much boot exclusively to OS 9. The iBook's 2 USB ports, I think, must be 1.1, and the Firewire port 400. (The Apple System Profiler, under Devices and Volumes, shows the number 1.5.9 for the USB ports, and 2.8.7 for the Firewire port. Is this an indication of the speed?)

There's no problems copying files to the external drive, but occasionally, when I've tried to open and/or edit those files, it's caused the iBook to freeze. Do you think this could be due to the drive being 2.0 and my iBook's USB ports being 1.1?

Something else I noticed, was that the Apple System Profiler occasionally indicated that one of the USB ports was connected to the Apple internal modem, as well as the external drive. I have no idea why, and it didn't appear all the time. I disabled two modem extensions (Internal USB Modem & Internal V.90 Modem), and it got rid of that situation, but the occasional crashes are still happening.

So do you think the USB speed mismatch could be responsible for the crashes when accessing files on the external hard drive?

iMac G3, iBook G3, Mac OS 9.2.x, iMacG3: 400 MHz; 64 MB; 10 GB. iBookG3: 900 MHz; 640 MB; 40 GB
  • Thomas Bryant Level 6 (13,865 points)
    Hello! The usb speed isn't likely the culprit but I'd check the format of the ext drive (do a "get info" on the drive) and see if it's FAT332(Dos) instead of Mac format. Odd characters and long file names can cause problems for Fat32 formats. Tom
  • eww Level 9 (52,980 points)
    Like Tom, I doubt that the USB speed is the issue. But if I were you, I'd take the drive out of the USB enclosure and put it into a FireWire enclosure, thereby multiplying the drive's data transfer speed 30-40 times (and making the drive bootable, if there's an OS on it). Connecting a modern hard drive to a USB 1.1 port makes it intolerably slow, and there's no reason to put up with such torpor when you have a FireWire port available.
  • Texas Mac Man Level 8 (46,565 points)
    Your drive is USB 2.0 compatible, however, it operates at USB 1.1 speed because of your Mac's 1.1 speed. This table shows USB: Transfer Speed Compared to Other Technologies
    http://docs.info.apple.com/article.html?artnum=24531 A Firewire drive will operate faster than USB 1.1.

     Cheers, Tom
  • motc Level 1 (5 points)
    Thank you all for your thoughts and advice.

    I did format the drive for Mac OS extended, with the Mac OS 9 drivers box checked.

    The hard drive box appears to be sealed - no way to remove the drive and put it in a different enclosure. Guess I should have thought of that before.

    So is it the case, that a typical external hard drive can transfer data at a variety of different speeds; and it's the enclosure's interface (USB, Firewire, etc.) that determines what that speed will be?
  • Don Archibald Level 10 (101,350 points)
    Hi, motc -

    ...that a typical external hard drive can transfer data at a variety of different speeds...

    Only if it is designed to do so. For example, a Firewire 400 drive can not transfer data at FW800 speeds; and a USB 1.1 drive can not transfer data at USB 2.0 speeds.

    Some external drives have multiple interfaces - USB and Firewire, and perhaps more than one for each.

    ...and it's the enclosure's interface (USB, Firewire, etc.) that determines what that speed will be?

    Not exactly. The capability of the Mac and the OS running the Mac also determine the data throughput speed.

    For example, the built-in USB on your iBook G3 900MHz model is USB 1.1. Attaching a USB 2.0 drive will not change that - the best such a drive can do is USB 1.1 speeds, limited by the Mac itself. Fortunately most USB 2.0 devices are backward compatible with USB 1.1 - they will operate on a USB 1.1 connection, but only at USB 1.1 speeds.

    Similarly your iBook's built-in firewire is FW400 - it can not operate that bus at FW800 speed.

    For those models capable of using PCI cards (an iBook is not), a faster bus (USB, Firewire, or both) can be added that way - but whether such a drive will then be bootable depends on the Mac and the card.

    There are also other limiters - the OS. For example, even if a USB 2.0 bus is added to a G4 using a PCI card, when the machine is booted to OS 9 it can not use USB 2.0 speeds, only USB 1.1 speeds - OS 9 does not have the necessary software components to drive USB 2.0.
  • motc Level 1 (5 points)
    Don, I should have known there would be more than a few factors involved. Afterall, these are computers, right?

    Thank you one and all for your help!