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freethought
Joined: 13 Mar 2005
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 Posted: Fri Apr 10, 2009 3:35 am Post subject: External HD problem |
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So I bought my first external HD a while back and I have a problem with it.
I have two laptops, one is a PC and one is a mac. I use the PC for my downloading, and I bought the HD to back things up on my mac and store excess downloads.
Anyway, the HD was first plugged into my PC, and I can transfer everything fine, but it wont seem to let me transfer/back up anything from my mac. It gives me an error message any time I try, saying that the HD can't be 'modified'.
It's supposed to be compatible with a mac, and I can transfer things from the HD to my mac. I have gone on the PC and set the HD to open to everything, but it still wont work on the mac, which says it's a read only device.
Anyone know what the problem would be? It's a Wyvo Fujitsu 320 gb, so not a low end drive.
Any help or insight would be appreciated. |
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Gatsby
Joined: 09 Feb 2007
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| Posted: Fri Apr 10, 2009 5:01 pm Post subject: |
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Did you format the drive with a Vista PC?
The default file format on Vista has compatibility problems with XP, so it may have problems with a Mac.
I am not certain of the details, but as I recall, if you format an external drive with Vista and leave it blank, then plug it in to an XP computer, the drive will be invisible.
Now that I think of it, if you partitioned a drive and had the root drive as NTFS, the old system, and the other partitions done in Vista, then tried using the drive with an XP computer (or installing XP on it), the other partitions might be invisible.
So, if you are using an external drive, either format it on an XP machine or figure out how to format it into NTFS on Vista.
Once your data is recorded, however, you have a problem. You could partition the drive, making the new drive NTFS. Then you could copy your data over to the NTFS side. And then you could re-format the first drive.
Whether this is the problem in you case, I am not sure. You need to check what file format the drive is formatted in, and whether it has a compatibility problem with Macs.
Perhaps someone else might know more about this than I do. |
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blackjack
Joined: 04 Jan 2006
Location: anyang
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| Posted: Fri Apr 10, 2009 5:47 pm Post subject: Re: External HD problem |
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| freethought wrote: |
So I bought my first external HD a while back and I have a problem with it.
I have two laptops, one is a PC and one is a mac. I use the PC for my downloading, and I bought the HD to back things up on my mac and store excess downloads.
Anyway, the HD was first plugged into my PC, and I can transfer everything fine, but it wont seem to let me transfer/back up anything from my mac. It gives me an error message any time I try, saying that the HD can't be 'modified'.
It's supposed to be compatible with a mac, and I can transfer things from the HD to my mac. I have gone on the PC and set the HD to open to everything, but it still wont work on the mac, which says it's a read only device.
Anyone know what the problem would be? It's a Wyvo Fujitsu 320 gb, so not a low end drive.
Any help or insight would be appreciated. |
It has nothing to do with vista.
Macs and windows use different formats. Macs can read from a windows formated drive but can't write, while windows can't even read from a mac formated drive.
When it says mac compatible, what it means is that the hardware (i.e external case) is compatible. If you want to back up from both pc and mac you will have to reformat as fat32 not NTFS. Bare in mind fat32 will not allow files over 4.?? gig.
There are programs to get over this limitation but as I don't have a mac maybe someone else can help. There are also a few different linux formats that you can use (that they use in NAS drives). But the simplest solution is to
A: reformat as fat32.
B: have two partions, one as mac one as windows and if you need to transfer data use a thumb drive (fat32) |
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blackjack
Joined: 04 Jan 2006
Location: anyang
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| Posted: Fri Apr 10, 2009 5:50 pm Post subject: |
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| Gatsby wrote: |
Did you format the drive with a Vista PC?
The default file format on Vista has compatibility problems with XP, so it may have problems with a Mac.
I am not certain of the details, but as I recall, if you format an external drive with Vista and leave it blank, then plug it in to an XP computer, the drive will be invisible.
Now that I think of it, if you partitioned a drive and had the root drive as NTFS, the old system, and the other partitions done in Vista, then tried using the drive with an XP computer (or installing XP on it), the other partitions might be invisible.
So, if you are using an external drive, either format it on an XP machine or figure out how to format it into NTFS on Vista.
Once your data is recorded, however, you have a problem. You could partition the drive, making the new drive NTFS. Then you could copy your data over to the NTFS side. And then you could re-format the first drive.
Whether this is the problem in you case, I am not sure. You need to check what file format the drive is formatted in, and whether it has a compatibility problem with Macs.
Perhaps someone else might know more about this than I do. |
I am pretty sure this is only a problem with the large capacity drives. If a drive is over 1.5 TB (???) vista selects a different drive format which is meant to be more efficient for large capacity drives. (I seem to remember reading this a while back) I have had no problem with 500-640gb drives |
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moosehead
Joined: 05 May 2007
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| Posted: Sat Apr 11, 2009 8:06 am Post subject: Re: External HD problem |
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| freethought wrote: |
So I bought my first external HD a while back and I have a problem with it.
I have two laptops, one is a PC and one is a mac. I use the PC for my downloading, and I bought the HD to back things up on my mac and store excess downloads.
Anyway, the HD was first plugged into my PC, and I can transfer everything fine, but it wont seem to let me transfer/back up anything from my mac. It gives me an error message any time I try, saying that the HD can't be 'modified'.
It's supposed to be compatible with a mac, and I can transfer things from the HD to my mac. I have gone on the PC and set the HD to open to everything, but it still wont work on the mac, which says it's a read only device.
Anyone know what the problem would be? It's a Wyvo Fujitsu 320 gb, so not a low end drive.
Any help or insight would be appreciated. |
I also have 2 nbs, one winxp and a macbook pro - and I do exactly as you describe - sometimes I download films on my win nb on the external and then unplug it and bring it over to my mac and upload it.
I have several externals, but only one I use for both machines.
on occasion, I have had an error message on the Mac, but not as you describe.
let me suggest a few things:
1) it's very important always to use the eject option, or "unplug external hardware" on a windows machine, eject on the mac. an external can be ruined by not doing this. if you didn't do it properly when leaving the windows machine, it can have an error when you go to plug it into the mac.
2) your mac might need some maintenance - do you do permissions and script checks/renewals on a regular basis? erase free space, etc? all those things make a difference. if not, download onyx and run the scripts, permissions, delete all the caches, etc. and reboot your mac. see if that helps.
3) plug the external into the win machine, as normal, then do a "safe to remove" hardware option; do this even if as we speak it's not connected to the win machine. if it's very old, you can also do a defrag on it, you know that right?
4) I had a LOT of connection problems not long ago and switched to a new cable and zap! just like that everything was fine. go figure.
see if any of this helps. if not post again or pm. |
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blackjack
Joined: 04 Jan 2006
Location: anyang
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| Posted: Sat Apr 11, 2009 9:21 am Post subject: Re: External HD problem |
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| moosehead wrote: |
| freethought wrote: |
So I bought my first external HD a while back and I have a problem with it.
I have two laptops, one is a PC and one is a mac. I use the PC for my downloading, and I bought the HD to back things up on my mac and store excess downloads.
Anyway, the HD was first plugged into my PC, and I can transfer everything fine, but it wont seem to let me transfer/back up anything from my mac. It gives me an error message any time I try, saying that the HD can't be 'modified'.
It's supposed to be compatible with a mac, and I can transfer things from the HD to my mac. I have gone on the PC and set the HD to open to everything, but it still wont work on the mac, which says it's a read only device.
Anyone know what the problem would be? It's a Wyvo Fujitsu 320 gb, so not a low end drive.
Any help or insight would be appreciated. |
I also have 2 nbs, one winxp and a macbook pro - and I do exactly as you describe - sometimes I download films on my win nb on the external and then unplug it and bring it over to my mac and upload it.
I have several externals, but only one I use for both machines.
on occasion, I have had an error message on the Mac, but not as you describe.
let me suggest a few things:
1) it's very important always to use the eject option, or "unplug external hardware" on a windows machine, eject on the mac. an external can be ruined by not doing this. if you didn't do it properly when leaving the windows machine, it can have an error when you go to plug it into the mac.
2) your mac might need some maintenance - do you do permissions and script checks/renewals on a regular basis? erase free space, etc? all those things make a difference. if not, download onyx and run the scripts, permissions, delete all the caches, etc. and reboot your mac. see if that helps.
3) plug the external into the win machine, as normal, then do a "safe to remove" hardware option; do this even if as we speak it's not connected to the win machine. if it's very old, you can also do a defrag on it, you know that right?
4) I had a LOT of connection problems not long ago and switched to a new cable and zap! just like that everything was fine. go figure.
see if any of this helps. if not post again or pm. |
I thought Macs "just work"  |
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giraffe
Joined: 07 Apr 2009
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| Posted: Sat Apr 11, 2009 9:49 am Post subject: |
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It just has to do with the file system that your hard drive has. If its Fat32 you can go inbetween PC or MAc. If its NTFS itll only work on PC's and apparently only read on mac os..
This might give you some info though.
http://www.lifehack.org/articles/lifehack/how-to-read-and-write-ntfs-windows-partition-on-mac-os-x.html
On an other note, my friend had the same problem when he needed to transfer some stuff he ended up formating the Hd into a fat 32 format and seemed to work for him. |
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Gatsby
Joined: 09 Feb 2007
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| Posted: Sat Apr 11, 2009 7:26 pm Post subject: |
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A couple of points.
First of all, moosehead is not entirely correct. Ejecting may be important with Macs, but not with modern PCs. This has not been an issue with PCs since Windows 98. Unless you have read ahead cache enabled for the device.
http://www.bsiopti.com/ocart.html
As far as I can tell, read ahead cache is disabled by default these days.
I don't do the eject routine, unless I know the device is busy or thinks its busy, and have not had any problems. I have NEVER lost data from a external hard drive, flash drive or any other drive by just pulling it from the USB slot.
Just to reiterate my warning, not just for Macs, but anyone: Vista uses an entirely different formatting system that is not backward compatible.
Now, what other say about XP and Macs, NTFS and FAT, is correct. I guess if you want to use an external drive with Macs and PCs, you would format it in FAT32.
Here's what you get by default with Vista:
"GPT Protective Partition."
This is a newer form of partitioning than the older MBR partition. It was designed for Vista, and does not work with 32 bit Windows XP.
Microsoft:
"14. Can the 32-bit version of Windows XP read, write, and boot from GPT disks?
No. The 32-bit version will see only the Protective MBR. The EE partition will not be mounted or otherwise exposed to application software."
Also, it may be difficult to reformat the drive, though not impossible:
http://forums.techguy.org/hardware/554850-gpt-protective-partition.html
http://forums.techguy.org/hardware/530925-solved-gpt-protective-partition-unmountable.html
This new partition system was intended by Microsoft to make the enormous drives of servers more practical:
http://www.microsoft.com/whdc/device/storage/GPT_FAQ.mspx
However, it is used on all drives by Vista, regardless of size.
I don't think it is compatible with Macs, but can't say for sure.
As an aside, Macs have some wacky scheme with their hard drives instead of the periodic defragmenting system used on PCs. Jobs insisted, against the strenuous advice of his technical team, to have Macs continuously defragging their hard drives when you read and write. That's why Macs choke if you use all of your hard drive space - or more than 90 perent? If Macs are doing this on external drives, this could explain the danger of data corruption if you pull the drive without doing the eject routine first. |
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moosehead
Joined: 05 May 2007
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| Posted: Sat Apr 11, 2009 11:15 pm Post subject: |
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| Gatsby wrote: |
A couple of points.
First of all, moosehead is not entirely correct. Ejecting may be important with Macs, but not with modern PCs. This has not been an issue with PCs since Windows 98. Unless you have read ahead cache enabled for the device.
http://www.bsiopti.com/ocart.html
As far as I can tell, read ahead cache is disabled by default these days.
I don't do the eject routine, unless I know the device is busy or thinks its busy, and have not had any problems. I have NEVER lost data from a external hard drive, flash drive or any other drive by just pulling it from the USB slot. |
actually I'm not incorrect, but right on point. It is your post that is misleading.
In the future, you might realize it's really rude to say someone is "incorrect" just because you disagree. It also causes a disservice to the OP by confusing them when being presented with options that are misrepresented, rather than just saying there is more than one possible explanation.
now back to my original message - I believe I was quite clear that it's the Mac that does the "eject" and the PC that needs to have a "remove hardware safely" indication.
This is VERY important for BOTH pcs and macs. Just because you haven't experienced a problem yet, doesn't mean you won't in the future and over time, you certainly can.
I totally understand what you are saying, more than once I've jerked out my mp3 player when I was in a rush to go only to see that little warning message pop up - well it does so for a reason, you know?
next, Vista may very well be part of the problem but the OP hasn't said yet if Vista is the OS so perhaps one might ask about that first, huh?
as for worrying about the FAT drives - jees - I have 2 firewires, 2 non-firewires, numerous flash cards, the only ones that don't work on both Mac and the PC are the firewires - but then the firewires also have usb's on them so I can still read and write just not at firewire capability.
OP - there's simply NO need to reformat anything, really. Macs are quite temperamental because they really do a lot - more than a win machine 
so give it a go at some of my suggestions first before you start messing with your external's hardware. |
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moosehead
Joined: 05 May 2007
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| Posted: Sat Apr 11, 2009 11:18 pm Post subject: |
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| Gatsby wrote: |
| That's why Macs choke if you use all of your hard drive space - or more than 90 perent? If Macs are doing this on external drives, this could explain the danger of data corruption if you pull the drive without doing the eject routine first. |
oh yeah and a win machine doesn't care if you use more than 90%
uh huh, yeah ok...  |
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blackjack
Joined: 04 Jan 2006
Location: anyang
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| Posted: Sat Apr 11, 2009 11:48 pm Post subject: |
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| moosehead wrote: |
| Gatsby wrote: |
| That's why Macs choke if you use all of your hard drive space - or more than 90 perent? If Macs are doing this on external drives, this could explain the danger of data corruption if you pull the drive without doing the eject routine first. |
oh yeah and a win machine doesn't care if you use more than 90%
uh huh, yeah ok... |
I have three drives at close to 100% capacity no problems |
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freethought
Joined: 13 Mar 2005
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| Posted: Sun Apr 12, 2009 6:23 am Post subject: |
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Thanks to everyone for their responses. I had considered a few of the things that have been mentioned, but wanted some feed back before I proceeded with anything.
(I hate the fact that this site no longer sends me an email when people have replied....) |
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