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@xxxxxxxxxxxx> 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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