Member Avatar for S_Eye

Hello,

I recently came up with a tricky problem.
I have a set of DMG files stored on a Windows XP server (the DMG files are originally coming from a Mac OS X 10.4 system).

When I try to transfer the files to an external usb Hard disk the process hangs in the middle and it looks like there is no possibility to transfer the files to the external hard disk. (no problem in transfering other types of files)

The funny thing is that I can transfer the same files without any problems to another internal SATA drive in the same system or to another PC through the network.

I thought about broblems with the USB drives, I tried several different brands, formatted them several time, check for bad sectors and file integrity both on the origin hard disk and the destination USB disk without finding anything abnormal.

Do you have any idea, or way to solve the problem?

Cheers
LV

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Dani AI

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reported DMG images that copy fine to an internal SATA volume and across the network but consistently stall when written to several different external USB disks; ’s observation about low‑level link effects is relevant. Because multiple enclosures and a fresh format were already used, focus should shift to three areas: target filesystem limits, the USB host/power/driver path, and anything special about the DMG image itself.

File system vs file size: FAT32 has a single‑file size limit (~4 GB). A large DMG written to a FAT32 volume will fail partway or abort. Formatting the target as NTFS (or splitting the image on the Mac before transfer) removes that particular constraint and is a quick way to rule out filesystem limits.

USB host / power / firmware: intermittent power drops, a marginal cable, or an unstable controller/driver stack often present as mid‑copy hangs. Differences between front-panel and rear ports, or between controllers on the same motherboard, are diagnostic clues. A powered enclosure or powered USB hub, a different cable, or a separate USB controller card will isolate power/cable/controller causes. Updating the motherboard/chipset USB drivers and any enclosure firmware is a sensible next step.

Software stack and image format: on‑access scanners or filesystem filter drivers can stall large binary writes. System event logs will often show disk/USB/driver errors at the time of the stall; a capture with Process Monitor will reveal the failing I/O call. To separate image-format issues from transport problems, attempt a same‑sized dummy binary copy to the USB: success implicates the DMG (sparse/encrypted/sparsebundle formats); failure implicates the USB path. Using a copy tool that reports I/O errors (or examining event logs) will produce actionable error codes for the next step.

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Member Avatar for MidiMagic

I can think of a few possibilities, but they are not all-inclusive:

- The files may be in a form where they must occupy contiguous disk memory. Defragmenting the USB drive may fix this.

- The file may contain a code combination which is an escape sequence for USB.

- The format (as opposed to the file) of the hard disk may have tangled links. Do a chkdsk (or equivalent) on the source disk.

Member Avatar for S_Eye

I can think of a few possibilities, but they are not all-inclusive:

- The files may be in a form where they must occupy contiguous disk memory. Defragmenting the USB drive may fix this.

- The file may contain a code combination which is an escape sequence for USB.

- The format (as opposed to the file) of the hard disk may have tangled links. Do a chkdsk (or equivalent) on the source disk.

few additional explanations:
- I'm trying to copy to a freshly formatted USB disk. (formatted with the computer management tool of Windows XP)
- I have launched several times a CHKDSK e: /f /r (e: is the volume containing the files)

You are mentioning escape sequences for USB. This might be a possibility since the files are coming straight from an Mac OS X hard disk. I tried to find more info about USB escape sequences without success. Could you tell me more about this?

Cheers
LV

Member Avatar for MidiMagic

I don't kjnow your drive.

There are certain byte combinations for any communications link which are gobbled by the link itself. So any binary file protocol must be designed to avoid such combinations.

Member Avatar for S_Eye

I don't kjnow your drive.

There are certain byte combinations for any communications link which are gobbled by the link itself. So any binary file protocol must be designed to avoid such combinations.

Right! I guess that the Windows USB driver and the USB interface hardware should prevent this from happening. As far as I remember the USB protocol encapsulate the data into frames... so I assume (not sure on that) that the content/type of file is not playing any part in this.

The PC is running windows XP. The motherboard is an "Asus A8N-Sli deluxe" and has an AMD Athlon64 with an nVidia nForce4 chipset. (I'm not sure about the USB bridge chip). Fort the hard disk I've tryed 3 different USB drives from different makes so I believe it's not playing a part in this.

I'll try to update all the drivers and see what happens... :eek:

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