Mac/external HDD issues

So I have an old external harddrive I have been using with my new Macbook (Maxtor 250 gb from Best buy a few years back). I can read files from the harddrive and open them, but I am having issues putting files on the HD. I have been using it for several weeks, and at this point I don't think I have tried adding files to it until now. I can't even rearrange files on it.

Specifically, the error I get is: error writing untitled.m
Check if directory is read-only, or has been renamed or deleted (for trying to save a Matlab file)

I know this is probably a compatibility issue. Am I going to have to buy a new one? Or is there something I can try?

Thanks

I assume the ext/hd is from Windows? That would be an NTFS file system.
Some Macs can only READ NTFS; what release is your OS X?

10.6.4 (basically brand new Macbook pro 13") The harddrive is old and I did use it with Windows. I have been using it for awhile, and I guess I didn't notice problems because I was only taking stuff from my old computer onto the mac.

Is there some sort of drive that is compatible with both Mac and PC?

That is current enough that it should have R/W support ... I'll verify and get back to you

Yes, the original FAT (aka fat32 like Win/98 or vfat from Linux)
All the USB external drives less than or equal to 250gb come in FAT32.

Any Linux user can reformat into Fat32/vfat for you.

Not sure of Mac Formatting options - - it's been several years.

OS X 10.6 r/w support for NTFS

see this description

OS X hdd formatting

see this description

The Option of MS DOS is Fat32

Thanks a lot. I will try some of this stuff this weekend. I'll let you know if it works or not.

First of all, I do want to be able to use the hd for both mac and windows, so I want to make it r/w compatible.

I don't know a lot about the terminal, but i did diskutil list, and this is what came up.

/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *250.1 GB disk1
1: Windows_NTFS 250.1 GB disk1s1

Do i use disk1 for the volume_name? Or do I use disk1s1?

Or should I just use the GUI that is on the website? I downloaded it but it kind of sketched me out so I didn't run it.

'names' are just labels and have nothing to do with the filesystem on them, so just bang the GUI and set as you please.

From day-1, compatibility (Mac+PCs+Linux) implied FAT32.
Issue: not so reliable and very wasteful of media space.

If at all possible, I would use NTFS. As you are in discovery mode, "try it, you might like it!".
Create a smallish partition, say 1GB and format it as NTFS.
Load some PC files to it, and then mount on your Mac and see where you are.
If R/O comes easily, the references above should help on getting R/W too.

Then you can make the call to use NTFS for the whole device (in one partition)
or whether you need to revert to FAT32;

hint: you'll need to format any FAT32 partition larger than 32 GB on some other OS, Windows is limited on FAT32 services -- for a reason