Breaking the 137 Gb limit : My AJBR uses 160 Gb

[PascalPe]

Hi,

I do not agree with the 137 Gb limit of the Archos Jukebox Recorder 20 with Rockbox ... and have a proof.

In june 2007, I replaced the original hard disk by an Hitachi Travelstar 5K160 - 160 Go 2"1/2 5400 RPM 8 Mo IDE from LDLC.
I spent sometime in test of partitionning and formating and after many tries, my Archos gave me the full 160 Gb space, even through the USB.

After have filled it with some large files, the windows (XP SP3) properties shows :

Capacity      : 160 000 147 456 bytes, 149 Gb
Used space : 160 000 114 688 bytes, 149 Gb
Free space  :                 32 768 bytes, 32,0 Kb

So, breaking the 137 Gb is doable.

The problem is ... that I do not remember WHAT I did exactely.
I remember to have tested many formater software from HD manufacturer or from the internet, with the help of some RockBox and internet pages.

I probably have formatted the drive with a 32k block size : if I add only ONE small file (a few bytes), the disk is full and windows reports 0 byte free.


The BigDisk page mentions that the limit is due to LBA28 (28 bits LBA address).

If I compute (2^28) * 32768 = 8 796 093 022 208 that is larger than the 137 Gb limit.

The price is that I can lost until 32767 byte per file, that is low in regard to any MP3 file.  But I would have been better to format it with only 1024 byte per block, that would enable a suffisant space : 256 Gb
As I have around 35000 files on the drive, I could save around 546 Mb, assuming that the average lost place is half the block size.

Pascal

[gevaerts]

Hi,

I do not agree with the 137 Gb limit of the Archos Jukebox Recorder 20 with Rockbox ... and have a proof.

Maybe you do have a proof, but this post does not convince me

In june 2007, I replaced the original hard disk by an Hitachi Travelstar 5K160 - 160 Go 2"1/2 5400 RPM 8 Mo IDE from LDLC.
I spent sometime in test of partitionning and formating and after many tries, my Archos gave me the full 160 Gb space, even through the USB.

After have filled it with some large files, the windows (XP SP3) properties shows :

Was the disk in the archos when you copied all files? Can you access all data over usb?

The BigDisk page mentions that the limit is due to LBA28 (28 bits LBA address).

If I compute (2^28) * 32768 = 8 796 093 022 208 that is larger than the 137 Gb limit.

That is indeed larger, but it's also meaningless. LBA has nothing at all to do with FAT cluster size, it's about sectors.

[PascalPe]

Was the disk in the archos when you copied all files? Can you access all data over usb?

Yes, through USB. I done that fill test this morning, to be sure.

That is indeed larger, but it's also meaningless. LBA has nothing at all to do with FAT cluster size, it's about sectors.

Any explanation will be helpfull...
It works, but I do not know why, and I would be happy to know how to redo it to replace the HD of the Archos of a friend ! :-)

Is the LBA blocksize always the same than the sector size ? Or can I have formated the drive with a sector size of 32k

I'm looking for a tool that would enable me to inverstigate, through USB if possible. If I still do not understand, I will reopen the archos and try to read directely the drive from the PC.

Edit:
The last moment idea... Attached is the drive properties screen capture. Would it be possible that windows displays erroneus values ?

Pascal

[torne]

Is the LBA blocksize always the same than the sector size ? Or can I have formated the drive with a sector size of 32k

Yes, the LBA number refers to sectors of 512 bytes. ATA is always addressed in multiples of 512 byte sectors.

The last moment idea... Attached is the drive properties screen capture. Would it be possible that windows displays erroneus values ?

Windows displays values calculated from the filesystem's boot parameter block, which is at the beginning. If the filesystem was formatted as 160GB then Windows will say 160GB. This is not affected by the limitation of the MSC bridge chip - only the ability to actually *access* the sectors near the end of the disk is missing.