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What does "WCHS" in partinfo mean?

PostPosted: Mon Nov 28, 2016 11:38 am
by sigi
What does "WCHS" in partinfo mean?

Partinfg (example attached) shows in the headline describing the hard drive CHS and WCHS data. What does WCHS stand for? I could not find this abbreviation neither on terabyteunlimited.com nor with Google.

While at partinfg, could you please explain the data and their meaning in the diffent columns of the table or give a link to a document that contains this exlplanation?

Re: What does "WCHS" in partinfo mean?

PostPosted: Mon Nov 28, 2016 8:55 pm
by TeraByte Support
windows reported chs values.


"sigi" wrote in message news:12905@public.bootitbm...

What does "WCHS" in partinfo mean?

Partinfg (example attached) shows in the headline describing the hard drive
CHS and WCHS data. What does WCHS stand for? I could not find this
abbreviation neither on terabyteunlimited.com nor with Google.

While at partinfg, could you please explain the data and their meaning in
the diffent columns of the table or give a link to a document that contains
this exlplanation?


Re: What does "WCHS" in partinfo mean?

PostPosted: Tue Nov 29, 2016 8:42 am
by sigi
Thank you.
A short explanation of the differences in the Terabyte and Microsoft calculation methods would be helpful.

Re: What does "WCHS" in partinfo mean?

PostPosted: Tue Dec 06, 2016 11:27 am
by sigi
Is the difference in calculation methods so well known or so unimportant that nobody cares to answer or to support my request for an answer?

Perhaps a link to an explanation would do.

Re: What does "WCHS" in partinfo mean?

PostPosted: Tue Dec 06, 2016 11:29 am
by TeraByte Support
it just reports the values for support.


"sigi" wrote in message news:12941@public.bootitbm...

Is the difference in calculation methods so well known or so unimportant
that nobody cares to answer or to support my request for an answer?

Perhaps a link to an explanation would do.


Re: What does "WCHS" in partinfo mean?

PostPosted: Tue Dec 06, 2016 7:24 pm
by sigi
Do you mean support rendered by Terabyte or Microsoft to me if I have a problem with partitions?

Is the difference in calculation methods so unimportant and on the other hand so complex that it is not worth the effort of explaining?

Re: What does "WCHS" in partinfo mean?

PostPosted: Tue Dec 06, 2016 8:11 pm
by Brian K
You can use WCHS cylinders in this calculation...

http://www.deathwombat.com/diskgeometry.html

WCHS cylinders don't rollover after 1024.

Re: What does "WCHS" in partinfo mean?

PostPosted: Thu Dec 08, 2016 10:37 am
by sigi
Thank you for giving me the keyword "diskgeometry" I can search for in Google.
However, this gives me a lot of hits but none of them mentions WCHS including your link.

Your reference to "rollover" does not tell me anything. What does it mean?

Re: What does "WCHS" in partinfo mean?

PostPosted: Thu Dec 08, 2016 12:58 pm
by Brian K
The CHS system is archaic and can't read more than 1024 cylinders. WCHS will read the correct number of cylinders. Here is an example from my SSD. Disk Management shows it as 447.13 GiB. WCHS shows 58369/255/63

1 cylinder = 255*63 = 16065 sectors = 16065*512/1000 = 8225.28 KB = 8.22528 MB

8.22528 MB = 8.22528/1.024^3 = 7.6604 MiB

58369 cylinders = 58369*7.6604/1000 = 447.13 GiB

Re: What does "WCHS" in partinfo mean?

PostPosted: Fri Dec 09, 2016 6:39 pm
by sigi
Thank you Brian for this very helpful explanation.