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New year's challenge


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#1 Wonko the Sane

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Posted 24 December 2010 - 01:20 PM

It is quite rare to see what should theoretically behave as a linear function look like a (malformed) spring.

I am attaching three graphs.
The last one is just an initial subset of the second one.

All I can tell you now is:
  • it's data extracted from the result of a rather common 2K/XP/2003 command with two different switches
  • anyone would expect a linear behaviour of these data


Let see if anyone can understand what the data represent.....

....I will post solution in 2011. :sleeping: :happy_dance:

Have fun... :frusty:

:wacko:
Wonko

Attached Thumbnails

  • graph1.jpg
  • graph2.jpg
  • graph3.jpg


#2 Mikorist

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Posted 24 December 2010 - 01:31 PM

Let see if anyone can understand what the data represent.....


You follow our SEO trends in your old ages, that is really strange :frusty:

#3 karyonix

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Posted 24 December 2010 - 03:17 PM

:frusty: I guess.
Spoiler


#4 Nuno Brito

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Posted 25 December 2010 - 11:33 PM

Just to toss my idea onto the game:
Spoiler


:whistling:

#5 Wonko the Sane

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Posted 26 December 2010 - 11:09 AM

XCOPY /J ? :)

http://ss64.com/nt/xcopy.html

http://technet.micro.../cc771254(WS.10).aspx

/j
Copies files without buffering. Recommended for very large files. This parameter was added introduced in Windows Server® 2008 R2.


  • it's data extracted from the result of a rather common 2K/XP/2003 command with two different switches


:)

:cheers:
Wonko

#6 Mikorist

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Posted 26 December 2010 - 12:22 PM

there are too many unknown parameters - based on numbers

I have no idea but looks like unix dd command from my point of view

dd for DOS? :)

#7 Mikorist

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Posted 26 December 2010 - 03:11 PM

Do not just say that is "reboot command"

I'll kill myself :)

#8 Wonko the Sane

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Posted 26 December 2010 - 04:27 PM

Do not just say that is "reboot command"


Naaah, but I can give you as little as 16 bytes for that:
http://reboot.pro/7119/

OT, but not much, please find attached a graph on the results of using Nada :) :
http://www.bernardbe.../NaDa/index.php
MIA :) , courtesy of Wayback Machine:
http://web.archive.o.../NaDa/index.php

:cheers:
Wonko

Attached Thumbnails

  • graphnada.jpg


#9 Nuno Brito

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Posted 27 December 2010 - 07:03 PM

/j
Copies files without buffering. Recommended for very large files. This parameter was added introduced in Windows Server® 2008 R2.

Too much wine during the holiday season. I need more coffee.. :dubbio:

#10 Mikorist

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Posted 02 January 2011 - 09:57 PM

....I will post solution in 2011. :smiling9: :whistling:


:confused1:

#11 karyonix

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Posted 03 January 2011 - 06:15 AM

Don't worry. 2011 will not end soon. There is still plenty of time left for posting solution.
:confused1:

#12 Wonko the Sane

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Posted 03 January 2011 - 08:35 AM

And the WINNER IS ....

.... obviously karyonix :whistling: :confused1:


Now, that two only one independent sources haves confirmed that the FORMAT command can produce that senseless output, anyone that can try to put together an explanation?

To make it clear for the less experienced:
Did you know that you have a SMALLER FAT size in a FAT16 2048 Mb volume then in a 2047 Mb one (actually HALF the size)?

Which kind of logic (if any) could it be behind the way FORMAT behaves?

:smiling9:
Wonko

P.S.:
@HAL9000
this may interest you:
http://en.wikipedia....hanging_paradox

#13 TheK

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Posted 03 January 2011 - 12:07 PM

Did you know that you have a SMALLER FAT size in a FAT16 2048 Mb volume then in a 2047 Mb one (actually HALF the size)?

Which kind of logic (if any) could it be behind the way FORMAT behaves?


Double cluster size = half the amount of clusters = half the amount of files that can be stored? :dubbio:

#14 Wonko the Sane

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Posted 03 January 2011 - 12:57 PM

Double cluster size = half the amount of clusters = half the amount of files that can be stored? :dubbio:

Very good. :cheers:

Related (cluster sizes):
http://support.microsoft.com/kb/140365
http://technet.micro...y/cc940351.aspx
http://www.pcguide.c...tCluster-c.html

But the values are "sectors per FAT" (they are not dependent on how many sectors are in a cluster). :unsure:

Nonetheless the vertical "steep-down" happens at each cluster size change, even on FAT32.

And what about the smaller "demented spring" in FAT 16 at 8 Mb (probably a FAT12->16 shift :)) with 512 bytes cluster?

Or, what about the ones between 2 and 3 and 4 and 5? Still inside FAT12 realm.

I am attaching the spreadsheet that I used to build the graphics.
And also the as usual half-@§§ed batches I used.
They need IMDISK, mksparse and hexdump.
DO NOT even THINK of running them if you don't know where your towel is. :w00t:

:)
Wonko

Attached Files



#15 karyonix

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Posted 03 January 2011 - 12:57 PM

I did not confirm behavior of format command.
It is an answer that I think it makes sense.

Small cluster => Need large FAT. More economical when there are many small files.
Large cluster => Waste a lot of disk space when there are many small files.

FAT16 maximum number of clusters is 65518. There are 256 entries in 1 sector, so maximum number of sectors per fat is 256.
If disk size is larger than 512*(65518 + a few secors for root directory and FATs), it need cluster larger than 512 bytes.
if disk size is large, cluster size must be large so that number of cluster do not exceed 65518.
When number of clusters reach cluster-size thresholds, number of clusters drops to approximately half of maximum number, so number of sectors per FAT is approximately 128.

FAT12 is more limited than FAT16. Maximum number of clusters is only 4078.

FAT32 is made to avoid large cluster. It have plenty valid cluster number.
512-byte cluster is possible for disk size up to approximately 128GiB.
However, in Windows OS, very small cluster size is used only in very small disk volume where space is very limited.
4096 is the default cluster size for moderate size disk volume.

Virtual memory page size is 4096 bytes.
Cluster size that is multiple of 4096 => good performance for memory mapped file, disk cache, paging.

#16 Wonko the Sane

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Posted 03 January 2011 - 01:08 PM

I did not confirm behavior of format command.

I beg your pardon. :unsure:

Took it back. :dubbio:

:w00t:
Wonko

#17 Mikorist

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Posted 04 January 2011 - 12:07 AM

@Wonko :cheers:

this may interest you:

http://en.wikipedia..../wiki/Dd_(Unix)


dd command a hard drive formatting:

dd if=/dev/zero of=/dev/hda

there are too many unknown parameters - based on numbers

I have no idea but looks like unix dd command from my point of view

dd for DOS? :rolleyes:



#18 TheK

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Posted 04 January 2011 - 12:28 AM

dd command a hard drive formatting:

dd if=/dev/zero of=/dev/hda

That's zero filling, not formatting :cheers:

#19 Mikorist

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Posted 04 January 2011 - 12:57 AM

dd if=/dev/zero of=/dev/hda bs=512 count=1 :rolleyes:




hangman paradox :cheers:


-----------
FURTHER EDIT: Here is a quotation from the Wikipedia article about Disk Formatting:

"While it is generally impossible to perform a complete LLF on most modern hard drives (since the mid-1990s) outside the factory[11], the term "low-level format" is still used for what could be called the reinitialization of a hard drive to its factory configuration (and even these terms may be misunderstood). Reinitialization should include identifying (and sparing out if possible) any sectors which cannot be written to and read back from the drive, correctly. The term has, however, been used by some to refer to only a portion of that process, in which every sector of the drive is written to; usually by writing a zero byte to every addressable location on the disk, sometimes called zero-filling."


http://en.wikipedia....Disk_formatting

#20 Wonko the Sane

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Posted 04 January 2011 - 10:15 AM

Low-level formatting is ENTIRELY another thing, like formatting a floppy disk is (and VERY old SCSI and MFM/RLL drives were).

The term low-level formatting is still IMPROPERLY used by a lot of people that don't even understand what formatting means AND that never performed a low-level format (since they are simply too young to have ever even seen one of the old drives).

Wiping (or zero-filling) and formatting (with a file-system) are yet two other very different things.

The format command under 2K/XP NEVER zero-fills anything.
The format command under Vista :cheers: and 7 - unless you use the /q switch - ALWAYS zero-fills (or "wipes") BEFORE formatting.

:rolleyes:
Wonko

#21 Mikorist

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Posted 04 January 2011 - 02:05 PM

The format command under Vista :thumbup: and 7 - unless you use the /q switch - ALWAYS zero-fills (or "wipes") BEFORE formatting.

:cheers:
Wonko


I did not know this-thanks.

I never formatted - Windows 2K/XP in the classical way- when I used - I always kill the hard disk with zeros :rolleyes: - and then partition magic :thumbdown:

this is great information for 7 :cheers:

:cheers:

#22 Wonko the Sane

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Posted 04 January 2011 - 03:37 PM

I did not know this-thanks.

Reference:
OLD:
http://support.micro...kb/302686/en-us
NEW:
http://support.micro...kb/941961/en-us

:unsure:
Wonko