Messages in this thread | | | From | Martin Steigerwald <> | Subject | Re: Partitions: Amiga RDB partition on 2 TB disk way too big, while OK in AmigaOS 4.1 | Date | Mon, 18 Jun 2012 23:14:16 +0200 |
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Am Sonntag, 17. Juni 2012 schrieb jdow: > On 2012/06/17 14:06, Martin Steigerwald wrote: > > Am Sonntag, 17. Juni 2012 schrieb Geert Uytterhoeven: > >> On Sun, Jun 17, 2012 at 2:58 PM, Martin Steigerwald <Martin@lichtvoll.de> wrote: > >>> Am Sonntag, 17. Juni 2012 schrieb jdow: > >>> | JXFS 64 bit file system > >>> | > >>> | With AmigaOS 4.x a new file system has been introduced called > >>> | JXFS. It is a totally new 64 bit file system that supports > >>> | partitions up to 16 TB in size. It is a modern journalling file > >>> | system, which means that it reduces data loss if data writes to > >>> | the disk are interrupted. It is the fastest and most reliable > >>> | file system ever created for AmigaOS. > >>> > >>> http://www.amigaos.net/content/1/features > >>> > >>> Well I asked AmigaOS 4 developers about this issue as well. Lets > >>> see what they say about 2 TB limits. > >> > >> 16 TB = 2 TB * 8. Perhaps they increased the block size from 512 to > >> 4096? > > > > I hope to get anything back from the AmigaOS 4 developers. > > > >> block/partitions/amiga.c reads the block size from > >> RigidDiskBlock.rdb_BlockBytes, > >> but after conversion to 512-byte blocks, all further calculations > >> are done on "int", so it will overflow for disks larger than 2 TiB. > >> > >> Note that in your profile-binary.img, the field is 0x200, i.e. 512 > >> bytes per block, > >> so I'll have to get a deeper look into your RDB first... > > > > Okay, thanks! > > > > I did not get any information regarding the current size limit yet. > > > > Strangely on AmigaOS 4.1 all values seem to be fine except for the > > total sectors value. > > > And on Linux begin and end cylinders are correct, only size is off: > Ah, you DO know that "cylinders, surfaces, and tracks" are polite > fictions in AmigaOS, don't you? Start and End blocks are all that > matter on a real Amiga. The fictions arose because at first it was > thought they could be used to optimize disk accesses. Once drives > were notched these values became meaningless. So they're created on > the fly picking values out of the nose or something. (RDPrep tries > to find reasonable size factors for the total block counts.)
I know there are pure fiction on Linux as well. As in any other modern operating system.
Actually Media Toolbox shows both. Physical and logical sizes. See the screenshots I attached to the bug report.
> > merkaba:~> amiga-fdisk -l /dev/sdb > > Are you sure "amiga-fdisk" is not broken?
Not at all, but there is also the syslog.
> > Disk /dev/sdb: 3 heads, 16 sectors, 81396441 cylinders, RDB: 0 > > Logical Cylinders from 43 to 81396440, 24576 bytes/Cylinder > > > > Device Boot Mount Begin End Size Pri BBlks > > System /dev/sdb1 * 43 65536043 1572864024 0 > > 0 Linux native /dev/sdb2 * 65536044 78643244 > > 314572824 0 0 [unknown] /dev/sdb3 * 78643245 > > 81396440 66076704 0 0 Amiga FFS Int. > > > > But not only from the first, also of the second and third one it > > seems. > > > > 65536043 - 43 = 65536000 > > So the size in bytes is 24 times the byte offset of the start of the > next partition. Fascinating. Let's see. You are working in 512 byte > blocks it looks like. With RDBs in blocks that means you can get up to > 1099511627776 bytes, 2147483648 blocks, or 44739242. So you are > already WAY over what can be expressed in the 32 bit values in the > RDBs. So the software that prepared your partitioning needs some > repair work of some sort or something other than traditional Amiga FFS > format disks. > > The first thing on the agenda is "fixing" the partitioning software. Is > the version of Amiga FFS you are using cognizant of 64 bit values? If > not you will have to go to block sizes larger than 512 bytes. It looks > like 1k is suitable for this instance. Given the way Amiga FFS stores > data on the disk I'd go for 4k or 8k block sizes unless you have lots > of very small files.
Is there still something to fix in there? Just still catching up the mail exchange. From what I could see on AmigaOS 4.1 all seemed well. I already reported the negative sector count value.
Anyway, if there is an issue left we can discuss this privately. This would have nothing to do with Linux and I can make sure that current AmigaOS developers hear about your oppinion.
Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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