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Media Toolbox Partition Size Calculation

Posted: Sat Jan 04, 2014 6:37 am
by my_pc_is_amiga
For my hard drive, in the "disk geometry" window, block per cylinder is 48 and block size is 512 bytes.

In the "Editing partitions" window, the calculated size for the hard drive does not seem to be correct.
For 4962 cyl., it shows 0.114 GBytes , 116.273 MBytes but...

For 48*512*4962 = 116.297 MBytes and 0.114 GBytes (rounding to the nearest 1000th). The MBytes are off but GBytes calc. is okay -- some kind of rounding is happening that causes the other calculation to be off?

Re: Media Toolbox Partition Size Calculation

Posted: Sat Jan 04, 2014 7:47 am
by my_pc_is_amiga
Also, I see a negative number in "Total Sectors" for RDB/disk geometry editing window:

-387,938,128

Should be 3,907,029,168 -- so is this an overflow issue?

Re: Media Toolbox Partition Size Calculation

Posted: Sat Jan 04, 2014 12:36 pm
by Creols
Could you tell us what the total size of your HD is ?
What FS do you intend to choose ?


Creols

Re: Media Toolbox Partition Size Calculation

Posted: Tue Jan 07, 2014 5:13 am
by my_pc_is_amiga
It is a 2TB Segate ST2000DM S1E1 hardrive with a total of 81396441 cylinders and 512 block size.
My System parition is a 1024 byte SFS2 filesystem block size and my Work partition is a 512 byte SFS2 block size

Something slightly off topic but interesting:
I learned very recently that a kibibyte is 1024 bytes and that a kilobyte is now 1000 bytes (actually has been 1000 bytes since 1998)

http://en.wikipedia.org/wiki/Kibibyte

Re: Media Toolbox Partition Size Calculation

Posted: Tue Jan 07, 2014 6:47 am
by tonyw
48 blocks * 81396441 cylinders = 3907029168 blocks total. That is greater than 2 GB, so it is quite possible that MTB displays it wrongly. Disks of that size did not exist back in the days when MTB was written.

As for the inaccuracies, I agree with your calculations, but I can't explain them.

I'll file a BZ for the wrong "Total Sectors" problem. These days it should be a 64-bit integer.

Although the official kB/kiB meanings changed some time ago, not many people use them. Most are stuck in the kB/MB/GB days (myself included).

Re: Media Toolbox Partition Size Calculation

Posted: Tue Jan 07, 2014 8:42 am
by Creols
my_pc_is_amiga wrote:It is a 2TB Segate ST2000DM S1E1 hardrive with a total of 81396441 cylinders and 512 block size.
My System parition is a 1024 byte SFS2 filesystem block size and my Work partition is a 512 byte SFS2 block size
It's seems to me that SFS\2 file system has to be always 512 blocks.

Usually System partition does not need to be greater than 2 Go. Software must be on a separate partition.


Creols

Re: Media Toolbox Partition Size Calculation

Posted: Tue Jan 07, 2014 5:58 pm
by salass00
my_pc_is_amiga wrote:Also, I see a negative number in "Total Sectors" for RDB/disk geometry editing window:

-387,938,128

Should be 3,907,029,168 -- so is this an overflow issue?
3,907,029,168 is -387,938,128 when it is read as a 32-bit signed value (2's complement) so it is most likely a limitation in the GUI element used to display the number.