Partition size and FAT32 cluster size?

[Thomas Mueller]

What is the biggest partition size compatible with 4096-byte (4 KB) cluster size, cluster
size being the minimum amount of space taken by a file however small?

I googled some years ago and found it to be about 8 GB, however now I wonder if that was
wrong, and I can accommodate a bigger partition.

>  From what I read years back, minimum cluster size would
> go to 8 KB when partition size goes above 8 GB, 16 GB when partition size goes above 16
> GB, 32 KB when partition size goes above 32 GB, meaning a lot of disk space wasted by
> small files. 
I believe the best file system ReactOS can use so far is FAT32, true also for FreeDOS.

My first formatting might be done from FreeBSD, NetBSD or Linux, since I don't have
ReactOS or MS-Windows installation currently.

Tom

[João Jerónimo]

On 07-12-2014 10:07, Thomas Mueller wrote:
>   What is the biggest partition size compatible with
> 4096-byte (4 KB) cluster size, cluster size being the minimum amount of space taken by a
> file however small?
>
>  I googled some years ago and found it to be about 8 GB, however now I wonder if that was
> wrong, and I can accommodate a bigger partition. 
I'm not sure, but..... in
FAT32, there are 28 bits to address the 
cluster number. (But FAT entries are 32-bit aligned.)
So...
4*1024*(2**28)  = 1TB
So the maximum size of the filesystem with 4KB clusters is about 1TB; I 
say "about" because there are some reserved cluster numbers...
It is possible that my math is bogus. :-)

>   I believe the best file system ReactOS can use so far
> is FAT32, true also for FreeDOS. 
Off-topic: One can write file-system drivers for
DOS, using the 
REDIRECTOR feature...

JJ

[Thomas Mueller]

On 07-12-2014 10:07, Thomas Mueller wrote:
>   > What is the biggest partition size compatible
> with 4096-byte (4 KB) cluster size, cluster size being the minimum amount of space taken
> by a file however small? 
> >   I googled some
> > years ago and found it to be about 8 GB, however now I wonder if that was wrong, and I can
> > accommodate a bigger partition. 
>  I'm not sure, but..... in FAT32, there are 28
> bits to address the cluster
>  number. (But FAT entries are 32-bit aligned.)
>  So...
>  4*1024*(2**28)  = 1TB
>  So the maximum size of the filesystem with 4KB clusters is about 1TB; I say
>  "about" because there are some reserved cluster numbers...
>  It is possible that my math is bogus. :-) 
> >   I believe the
> > best file system ReactOS can use so far is FAT32, true also for FreeDOS. 
>  Off-topic:
> One can write file-system drivers for DOS, using the REDIRECTOR
>  feature... 
>   JJ 
I googled again, apparently what I got previously was MS recommendations for Windows.

Larger partition sizes on FAT32 with 4 KB cluster size could mean slow disk access, but I
guess it would be OK to use FAT32 with 4 KB cluster size for 16 GB or 32 GB USB sticks, or
hard-drive partitions should I order an old clearance-priced refurbished SATA hard drive.

I'm reluctant to do heavy compiling on a USB stick; or FreeBSD or Linux with Wine for
ReactOS or DOSBox for FreeDOS.  Then I could use BSD or Linux filesystem.

I've never actually run ReactOS.  Closest I came was burning installation CD for
0.3.15 and finding it wouldn't boot.

Tom

[David Quintana (gigaherz)]

Note that because flash drives tend to have larger sectors and specially
much bigger erase groups, it's often more interesting to format flash
drives as 16k rather than 4k, even if it can waste some space with small
files.

On 8 December 2014 at 03:48, Thomas Mueller <mueller6723(a)twc.com> wrote:

>   On 07-12-2014 10:07, Thomas Mueller wrote:
> >   > What is the biggest partition size
> > compatible with 4096-byte (4 KB) 
>  cluster size, cluster size being the minimum
> amount of space taken by a
>  file however small?
>
> >   > I googled some years ago and found it to be
> > about 8 GB, however now I 
>  wonder if that was wrong, and I can accommodate a bigger
> partition.
> >   I'm not sure, but..... in FAT32, there are 28
> > bits to address the cluster
> >  number. (But FAT entries are 32-bit aligned.)
> >  So...
> >  4*1024*(2**28)  = 1TB
> >  So the maximum size of the filesystem with 4KB clusters is about 1TB; I 
>  say
> >   "about" because there are some reserved
> > cluster numbers...
> >  It is possible that my math is bogus. :-) 
> >   > I believe the best file system ReactOS can
> > use so far is FAT32, true 
>  also for FreeDOS.
> >   Off-topic: One can write file-system drivers for
> > DOS, using the 
>  REDIRECTOR
> >   feature... 
> >   JJ 
>  I googled again, apparently what I got previously was MS recommendations
>  for Windows.
>
>  Larger partition sizes on FAT32 with 4 KB cluster size could mean slow
>  disk access, but I guess it would be OK to use FAT32 with 4 KB cluster size
>  for 16 GB or 32 GB USB sticks, or hard-drive partitions should I order an
>  old clearance-priced refurbished SATA hard drive.
>
>  I'm reluctant to do heavy compiling on a USB stick; or FreeBSD or Linux
>  with Wine for ReactOS or DOSBox for FreeDOS.  Then I could use BSD or Linux
>  filesystem.
>
>  I've never actually run ReactOS.  Closest I came was burning installation
>  CD for 0.3.15 and finding it wouldn't boot.
>
>  Tom
>
>
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