View Full Version : 2GB File size limit with DVD-RAM

04-27-2001, 11:17 PM
Does the Mac OS still have a 2GB file size limit? I have a G4 500 DP with 512MB Ram and a 4.7GB DVD-RAM running 9.0.4. I can't seem to copy files that are over 2GB in size to a DVD-RAM disk. Whenever I try I get an error -40. I was able to copy a 1.66GB file, but not a 2.15GB file. As a reference, 4.7GB disks format to 4.26GB free.

Is this a limitation of UDF, the Apple DVD drivers, or am I just crazy?


04-28-2001, 12:02 PM
From what I know, it's a limitation of the MacOS. OS 9 and later don't have the problem as far as I know.

04-28-2001, 01:01 PM
Beginning with OS9, the File Manager file size limitation is now "2 to the 63rd power" bytes in size, whatever that works out to, but, yes, greater than 2GB. However applications have to also support the larger size. Apparently some still don't. Not sure if there is any list of those that don't. k

04-28-2001, 01:19 PM
The OS does not have a problem, since I have already created the file. I just can't copy it toa DVD-RAM disk. I can copy the file from one hard disk to another. Is there a limit that someone knows of in the Apple DVD driver? Is there a third party driver that will work?


04-28-2001, 01:32 PM
Info about Intech CD/DVD SpeedTools http://www.macgurus.com/shoppingcart/showrampage.cgi?intechsoftware.html

You could try the demo. k

04-28-2001, 02:32 PM
I installed the CD/DVD SpeedTools demo, and I get the same error when I try to copy a file over 2GB to the DVD-RAM. Do the Great Gurus have an Apple OEM DVD-RAM drive they could try? Is this problem unique to my machine?


04-30-2001, 09:57 AM
Maybe you need to go to 9.1?

Is there an update for the DVD-RAM driver?
Have you tried the INTECH demo? They work fairly well, but I've never used a DVD-RAM. A friend of mine has one, but I havent heard of any issues. Have you tried to copy a folder with several files that total over 2GB? or is this only a single file size limitation?

04-30-2001, 10:09 AM
Yes I tried the Intech demo (latest version downloaded three days ago). It provided the same result as the Apple drivers.

This limit is on single files. I am trying to copy large video files (up to 4 GB in size). I haven't tried multiple files, as success with this would not matter for me.

04-30-2001, 10:24 AM
The core of Mac OS 9 does support file sizes over 2 GB, but not all of the OS does. For instance, Appleshare cannot transfer files over 2 GB, it just does not support them. It is my guess that the tool that OS 9 uses to write to DVD-RAM discs also has this anomaly. I have no idea how you might fix this problem other than wait for new versions of software or to try OSX.

- Chris

05-05-2001, 02:57 PM
I think Toast Titanium supportd DVD-RAM - it might just allow a 2GB or larger file. Check out the site. I just got a couple copies - one for work and one for home. Its pretty good, but all I do is CD-r


05-05-2001, 03:39 PM
This problem is becoming pervasive I suspect. I just ran into it with Solaris 5.5 and had to upgrade the entire OS to Solaris 5.8 on a Sun workstation to get the OS to see files greater than 2^31=2,147,483,648 bytes.

You're obviously correct that the "OS" (the Finder for sure) doesn't have any problem with file sizes larger than 2 Gb if you can see them. It's sort of a guess, but are you running the newest Firewire extensions (2.5). I think I recall some sort of fix with these drivers that allowed file sizes greater than 2Gb.

05-05-2001, 05:13 PM
Thanks for additional suggestions. I will give Toast 5 a try. It is sort of a pain, since this should not be necessary for DVD-RAM.

As far as Firewire drivers go, this is an internal IDE drive (Apple OEM, the base 500 DP came with DVD-RAM) so I don't think this should be an issue.

05-06-2001, 12:27 AM
No one seems to have mentioned volume formatting yet. If a disk is formatted as regular HFS, its max file size is 2GB regardless of anything else. See http://til.info.apple.com/techinfo.nsf/artnum/n8647

Since HFS+ allows 2TB file sizes (**IF** the machine is running 9.0 or better, see http://til.info.apple.com/techinfo.nsf/artnum/n24601 footnote 3), and since you're running 9.0.4 and are able to create a > 2GB files on HD and copy it between HDs, but unable to copy it onto a cart, well, it sure sounds suspicious.

One side of a 4.7GB DVD-RAM s well within the *volume* size limits for regular HFS, but a side just exceeds its filesize limit, ergo the OS won't put a file on there that completely fills the side. I'll bet that cart just didn't get formatted HFS+. Worth a look before worrying about drivers, for sure.

OS error -40 == "tried to position before start of file", consistent with a variable overflowing: the value wraps around to -1 and the OS (cleverly) refuses to write at a position -1 relative to the start of the file. To avoid making programs special-case different volume formats, the File Manager emulates the HFS+ functions on behalf of volumes that don't support them directly. But the emulation naturally can't overcome limitations of the underlying format, so when Finder tries to allocate that 2GB + 1th byte, it makes sense that an error -40 might bubble up from the lower levels....

[This message has been edited by BMonk (edited 06 May 2001).]

05-06-2001, 08:22 AM
Interesting ideas for me to look at. A couple of points though--4.7GB DVD-RAM discs are 4.7GB per side (9.4GB total). They format to about 4.26GB per side.

Also, I believe they are formated as UDF, rather than HSF or HSF+. I believe this is the format used for data on DVD media.

05-06-2001, 11:18 PM
sounds like you've got a new machine. guess I should have asked what you had before I assumed you had an external drive attached... anywayz, seems like you basically know what you're talking about. have you asked apple via tech support (free 90 day) if you DO have a new machine? is this a "super-drive?" if so I recall (probably incorrectly) that there were file size limitations put on the size of movies that folks could write to DVDs with the iDVD software. maybe these limitations are applied through drivers somehow. anyhoo, beyond what has been discussed here this is certainly beyond me, so good luck to ya... sounds like an apple question at this point, eh?

05-08-2001, 12:40 AM
>>A couple of points though--4.7GB DVD-RAM discs are 4.7GB per side >>(9.4GB total). They format to about 4.26GB per side.

Well, if you go to buy media, MO, WORM, DVD, they call them by the total size of the disk including both sides, so I thin of those as 9.4GB disks. Thought you were using the next size down, 5.2GB (which some people call by its formatted size, about 4.7GB or 2.35 per side).

05-08-2001, 01:22 AM
>>Also, I believe they are formated as UDF, rather than HSF or HSF+. I >>believe this is the format used for data on DVD media

I just looked at some of my 5.2GB DVD-RAM disks.

The ones formatted by the old DVD-RAM TuneUp utility are "Mac OS Extended" i.e. HFS+. The ones formatted by Intech CDST are standard HFS: I suppose I must have just hit OK when using the Finder's Erase Disk command and not selected Extended from the popup. Doesn't make much difference on a 5.2 disk since a side is so close to the max file size, but on 9.4s it definitely would make a difference for someone using huge files.

According to http://til.info.apple.com/techinfo.nsf/artnum/n60235 UDF is but one possibility. The two native Mac formats are also supported, as is (God help us) DOS!

UDF isn't even offered as a choice when erasing a DVD-RAM in the Finder, at least not hear under 9.1. The TIL article above seems to indicate UDF format can be chosen in Drive Setup, but DS thinks my non-Apple DVD-RAM drive is a CD-ROM and won't enable the Initialize button, so I can't get that far.

In any case, be interested to hear what format the disks turn out to be.

05-08-2001, 05:13 AM
bill, I bow in your general direction.


05-08-2001, 07:59 AM
I refer to the disks as 4.7, rather than 9.4GB because they are single sided. You can buy DVD-RAM disks in 4 sizes that I know of: 2.6 (single sided), 5.2 (dual-sided), 4.7 (single sided) and 9.4 (single sided). To make it more complicated, they come in Type 1, Type II and non-cartridge varietes. Type I (all dual sided, and some single sided) are fixed in their cartidges. Type II are single sided disks that can be removed from their cartidges. The cartidges are like old style CD-ROM caddies. There are also non-cartridge disks (only single sided) that ship in CD-ROM like jewel cases. The reason you would want to have a DVD-RAM that is not in a cartridge is so it can be read in a DVD-ROM drive.

In this case, I am using a single sided 4.7GB non-cartidge disc. That is why I refer to it as 4.7GB, rather than 9.4GB. I will try to reformat it.

Thanks for the suggestion.

05-08-2001, 08:01 AM
Sorry-an error in my last post. 9.4GB dics are dual-sided.

05-08-2001, 09:09 AM
Another update in the Saga. I reformatted the disk to HFS+, and I can now copy files over 2GB to the disk. I also tried formatting for DOS. Seems this is bug and bad things happen if you try it. The disk becomes unrecognizable, and must be reformatted.

So, the problem is with UDF. This is bad, since I want to exchange disks with Windows users, and I don't want them to have to run a utility to read HFS+ disks.

Any more ideas?

05-08-2001, 10:51 PM
>>I reformatted the disk to HFS+, and I can now copy files over 2GB to the disk.


>>also tried formatting for DOS.....bad things happen if you try it.

That's part of the DOS design, isn't it? http://macgurus.com/infopop/emoticons/icon_biggrin.gif

>>So, the problem is with UDF. This is bad, since I want to exchange
>>disks with Windows users, and I don't want them to have to run a
>>utility to read HFS+ disks.

There are at least four versions of UDF (see http://www.osta.org/html/ostaudf.html) and I dunno the differences between them. Just browsed the 2.01 spec and it is so abstract that dumb questions like "what's the max file size?" are neither asked nor answered. A few days study might reveal the answer, but it'd be less painful if a UDF expert would step in....

Also, dunno which UDF version is implemented in which version of Apple's UDF Volume Access extension. OS 9.1 and 9.0.4 ship with the same extension version : 1.5.3. OS 8.6 has 1.5.2. Which UDF version do they contain? Searching Apple turns up nothing....

I don't have an OS 8.5 around to check, but 8.1 includes UDF Volume Access 1.0. That extension, according to Roxio http://www.roxio.com/en/support/udfmac/udfmacreadme.html implements UDF 1.02. How wacked is that? Anyway, to fix some problem, Roxio offers an extension (now itself pretty old) that implements UDF 1.5.

Say, UDF is native in OS X. I wonder what would happen if you formatted a UDF volume under X and then tried to copy the file? If it worked, might indicate the OS 9.x extension just doesn't use a recent enough version of UDF.

Or maybe UDF has a 2GB filesize limit. I'd find that hard to believe, but no one seems to be saying one way or the other. Did read somewhere that UDF (Which version? It didn't say) only allows one partition per volume. That surprised me, but perhaps that limitation is part of making it universal.