Talk:Universal Disk Format
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[edit] UDF partition identifier
What is the correct GPT or MBR identifier for UDF hard disk partitions? Chithanh 08:01, 17 April 2006 (UTC)
[edit] Flavors
I have added the flavors because somehow this information needs to be made available to UDF users. I've tried to explain it in both a technical way (which internally happens) as well as how it applies to the user who wonders why his UDF 1.5 compliant OS can't read his UDF 1.5 compliant UDF disc (as in the example of the Sony Mavica CDs).
I have not found a better word in place of "flavor" (or flavour) but if you have one, please update the text accordingly. Another one that came to mind was "variant" - however, since it's always hard to talk about these flavors, the more unique and outstanding this term is, the better, I think. Ask yourself: If you ask someone which "flavor" of UDF is on the disc, it may be better understood as if you'd ask him which "kind" or "subformat" he uses.
My knowledge may be outdated. I've been actively participating in the specification of UDF 2.00 (and 2.01), but not in later versions.
I am also not sure about DVD+RW - do its sectors wear out as they do with CD-RW and DVD-RW?
One more thing: I actually do have UDF 1.5 compliant test images for the Original, VAT and Spared format (as well as for Strategy 4096, which is rather seldomly used), made years ago when working for Adaptec. They used to be openly available from Adaptec's ftp server until they vanished when no one cared for them any more, apparently. I could publish these on a separate server if someone could suggest a public place for them. They're about 13MB in size together.
-- Tempel 07:38, 7 March 2006 (UTC)
- ftp://claunia.com/uploads/ (anonymous), you're welcome.
- Upload them and let me a message so I move them to an appropiate folder.
- Bandwidth isn't marvelous, but, it is a place.
- Regards —Claunia 15:31, 7 March 2006 (UTC)
- DVD-RW and DVD+RW have cyclability issues similar to CD-RW. Packets can be overwritten a limited number of times, after which they get tired/damaged as well.
- I removed the comment about Windows 2000 not being able to read UDF 1.50 spared or VAT.
- Media with sparing tables are detected as well. Windows 2000 requires the standard to be followed though. This means that the packet length must be set to 32 in the sparable partition descriptor. DVD media using UDF 1.50/Spared with a recorded packet length of 16 cannot be read by Windows 2000 without installing additional software.
- Given that there is no officially accepted errata RFC for UDF allowig other values there, I consider this a reasonable requirement.
- As for VAT, it is detected pretty well by Win2k. The main problem with getting Windows 2000 to detect UDF 1.50 + VAT formatted media, is drive support. Even on finalized media, many ROM drives have problems finding the last recorded sector properly. This, oddly enough, also highly depends on the quality of software for the recording drive. Typically drives have less problems with DVD+R media than with DVD-R.
- Still, Windows 2000 supports UDF 1.50 with VAT and with Sparable Partitions, according to the UDF standard.
- Pieter-Bas 08:00, 15 May 2006 (UTC)
The Pieter-Bas from Philips? Nice to see you here! Thanks for clarifying some questions. I had made tests with my old CD media I made at Adaptec/Roxio, and that was not read by Windows 2000 SP4. Odd, but if you say you were able to read such disks on Win2K, then I won't argue. Tempel 22:58, 25 May 2006 (UTC)
- Yep. The very same. Back then I spent a a week or two making sure my UDF 1.50 discs were actually read by Win2k SP4. Actually hooking up windbg and running in checked mode helps a lot there. If the media are refused, you can typically see why in the debug output. Still, problems always remain, especially when the drive can't reliably determine the disc properties. Pieter-Bas 15:37, 2 January 2007 (UTC)
[edit] limits
What is the maximum size for a file under UDF file system?--Ctac 07:52, 12 July 2005 (UTC)
- I think it's 1 GiB - and I base that solely on how DVD video files are segmented. Don't trust me. Tokachu 00:09, 25 July 2005 (UTC)
- Actually, it's 16 EiB. VOB files on DVD Video discs are broken up into 1 GiB chunks for backward compatibility with ISO 9660 and legacy operating systems. —Ghakko 15:30, 25 July 2005 (UTC)
- The reason for 1 GiB chunks has nothing to do with backwards compatibility. In a file's allocation descriptors that describe the chunks a file is composed from, the length of a piece is 30 bits wide i.e. 1 GiB since the top two bits are used to hold flags telling its allocated, freed, free or if its specifying a continuation descriptor. Reinoud 22:11, 4 January 2007 (UTC)
- Actually, it's 16 EiB. VOB files on DVD Video discs are broken up into 1 GiB chunks for backward compatibility with ISO 9660 and legacy operating systems. —Ghakko 15:30, 25 July 2005 (UTC)
- To answer the question, the maximum size of a file is indeed 64 bits i.e. 16 EiB though only when sparse. Current UDF versions upto 2.60 allow only one writable physical partition descriptor thus limiting the size to 32 bit sector numbers i.e. with 2 KiB sectors this makes 32+11=43 bits giving 8 Tib. When multiple physical partiton descriptors are allowed an additional 16 bits are available giving 59 bits i.e. a half EiB spanning the whole disc. Reinoud 22:11, 4 January 2007 (UTC)
[edit] InCD
Which UDF version do you suggest?
I think, 2.01 for cdrw.
Windows XP Pro SP2, LG GSA-4136B
The article says right now:
Lately, however, it has also become popular with large and fully rewritable cross-platform media such as:
* Flash media above the Microsoft FAT32 (Windows XP) limit of 32 GB per disc
According to the article File Allocation Table, FAT32 has a limit of 2 TiB, so the above statement is wrong in my eyes.
--Abdull 20:52, 28 November 2005 (UTC)
- Yes, but Microsoft has deliberately crippled the disk formatting tool in recent version of Windows. Basically, they want people to use NTFS, which is still not well supported by other operating systems e.g Linux, Mac OS X, and the BSD's. By limiting the size of FAT32 filesystems they provide a seemingly plausable reason to migrate. More subtle than simply dropping support outright. Imroy 07:00, 20 March 2006 (UTC)
[edit] what is Old and New Operating systems ?
Is discontrinued IBM OS/2 an example of OLD operating system? I bet it is. Is Windows (XP/2o03/forecoming Vista) example of New operating system ? I bet it is. But Windows cannot write to UDF without 3rd-party apps, while OS/2 can.
So splitting Operating systems to old and new is quite strange and confusing in this article.
- Wait a minute, WHAT OS/2 can write to UDF without 3rd-party?
- As far as I remember people in my local OS/2 user group must use 3rd-party to write UDF...
- Can you provide proofs?
- —Claunia 15:37, 7 March 2006 (UTC)
[edit] UDF Reader For Legacy OS
http://www.download.com/Adaptec-UDF-Reader-Driver/3000-2100_4-9497911.html
[edit] Write support needs flavor specification
The section "Native OS Support" lists supported UDF revisions along with broadly claiming write support in some cases, which is not always correct, because some of those File Systems only support Write for the plain flavor, but not for all UDF 1.5 or later flavors. Hence, the info there is incorrect giving the impression it supports writing to UDF 1.5 media such as CD-R when it, in fact, doesn't. An example are all OS X versions up to 10.4. They only write to plain random access media (old DVD-RAM, hard disks etc.) but not to -R or -RW media using the new flavors.
[edit] DVD+VR
Can somebody write this page? The DVD+VR one? There is not one thing on it and all the links to such a page go to an editing page.--Nytemunkey 06:45, 15 June 2006 (UTC)
- Done. Please check the DVD+VR page. I added a talk page with information of which I know it's missing. Pieter-Bas 15:39, 2 January 2007 (UTC)
[edit] 32 Gb limit on FAT32?
The article claims a 32Gb limit on FAT32 under Windows XP. The size limit for FAT32 is much larger than this. The only issue with Windows XP is that it will not format any device (or partition if appropriate) larger than 32Gb. However, larger than 32Gb devices otherwise work perfectly with XP.
Could it be referencing the 4GB single file size limitation of FAT32? 24.14.61.102 05:13, 9 March 2007 (UTC)
[edit] Please update "write" capabilities in the table
Since hardly any one had paid attention to the "flavors", I have added a note that states that by default, OSs do not support the VAT and Spared flavors but only the "plain" flavor.
Yet, some OS seems to support the flavors, some even in writing. E.g, Windows Vista supposedly supports VAT and Spared flavors even in writing. Can someone please verify this by writing both to a CD-R and a CD-RW in packet writing mode and then update the table accordingly? Please do not blindly believe it unless you have tested it. If in doubt, ask me - I have a lot of practical knowledge of UDF and packet writing and can help.
Thank you -- Tempel 08:06, 12 October 2006 (UTC)
[edit] Does Linux 2.6.x really support the Spared flavor in writing?
I am doubtful that Linux 2.6 supports writing to CD-RW in Spared flavor, but that's what the article suggests in the list of OS support at the bottom. Can someone confirm that it really includes support for this? Meaning packet writing to CD-RW where you can delete files and add files at will? I had a search for such a feature in Linux and could not find it myself. Could you point me to a spec or even the source code? -- Tempel 08:11, 12 October 2006 (UTC)
- There are two separate issues here:
- The Linux UDF driver supports read-write on any writeable block device. These include hard disk partitions, flash and DVD+RW discs (which I regularly use for simple backups).
- CD-RW discs are a special case; a separate driver is needed to do the background formatting and re-blocking to make the disc appear as a writeable block device.
- I have to point out, though, that performance is horrible when writing large numbers of small files.
- —Ghakko 13:05, 10 January 2007 (UTC)
[edit] Plain (Random Read/Write Access). This is the original format supported in all UDF revisions
This is wrong: the original format is read only partition as in UDF 1.0x. Rewritable partitions came only with UDF 1.50.
- Nope. UDF 1.02 is actually also intended to write, hence the 'reading' and 'writing' hints in the specification. As for partition types: The older UDF specifications didn't repeat anything that was not restricted or refined from ECMA167-2. Also, additional partition types (VAT and Sparable partitions) were introduced in UDF 1.50 to enable random access writing on packet-written media that are otherwise not randonly overwritable, such as CD-R and CD-RW. Pieter-Bas 15:46, 2 January 2007 (UTC)
[edit] UDF 2.50 on Linux
Stock Linux 2.6 kernels do not support UDF 2.50 at all, see http://linux-udf.cvs.sourceforge.net/linux-udf/udf/linux-2.6/udf_sb.h?revision=1.8&view=markup#l_7
There is a patch for read-only support floating around, but it has not been accepted yet (http://sourceforge.net/tracker/index.php?func=detail&aid=1476807&group_id=295&atid=300295). —The preceding unsigned comment was added by 68.126.150.3 (talk) 02:29, 8 January 2007 (UTC).
[edit] Unicode?
How does UDF store file names? Does it use Unicode? Shouldn't the fact it does or not be mentioned in the article?--Saoshyant talk / contribs (I don't like Wikipedophiles) 14:41, 17 January 2007 (UTC)
