Re: Exotic Blocksize 6144 Byte

From: Fabrizio <fabrizio.magni_at_mycontinent.com>
Date: Sun, 03 Apr 2005 19:00:21 GMT
Message-ID: <93X3e.730785$b5.33035485@news3.tin.it>

Fabrizio wrote:
> Mark D Powell wrote:
>

>> I do not claim to be familiar with the details of the NTFS file system
>> structure but if I remember from the manuals that covered formatting my
>> new harddrive back in the days when you upgraded PC rather than buy new
>> ones the 512k chunk on disk was the device sector size.  The OS
>> however, reads and writes multiple secotrs at a time.  This grouping of
>> sectors was called a cluster and generally was 2k, 4k, or 8k worth of
>> sectors at a time.  On any other system except Windows the cluster size
>> would be called the block size.  The cluster size dedended on the
>> size/mdoel of the disk drive and how it was partitioned.

>
>
> Checked and you are perfectly right about the cluster size in windows
> depending, usually, by the size of the formatted device. The only limit
> seems to be 4K so the OP shouldn't be able to have a ntfs with cluster
> size of 6k and as you pointed out there would be waste of i/o of 25% for
> every operation.
>
> Thank you for the clarification.
>

Never trust what you read on a newsgriup or a windows GUI.

Here what I have found in the format help (of a windows xp):

  /A:size Overrides the default allocation unit size. Default settings

                  are strongly recommended for general use.
                  NTFS supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K.
                  FAT supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K,
                  (128K, 256K for sector size > 512 bytes).
                  FAT32 supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K,
                  (128K, 256K for sector size > 512 bytes).

                  Note that the FAT and FAT32 files systems impose the
                  following restrictions on the number of clusters on a 

volume:

                  FAT: Number of clusters <= 65526
                  FAT32: 65526 < Number of clusters < 4177918

                  Format will immediately stop processing if it decides that
                  the above requirements cannot be met using the specified
                  cluster size.

                  NTFS compression is not supported for allocation unit 
sizes
                  above 4096.

No mention to 6k but... who knows... I'd like a spare partition for a test... *sigh*

Apologize for the previous posts.

-- 
Fabrizio Magni

fabrizio.magni_at_mycontinent.com

replace mycontinent with europe

Received on Sun Apr 03 2005 - 14:00:21 CDT