Re: Partition Problems w/ 810mb HD

[Gen Cerf <gen@nynexst.com>]

I think there might be some (alot of!) confusion here with respect to the
disk size discussion...

1) One million bytes is ALWAYS equal to 1 Megabyte... let's not
   rewrite the math books to fit the problem! 

2) If the drive were actually 810 Megabytes large instead of 810 Megabits
   then that would be equal to  8 * 810 * 10**6 = 6480 * 10**6 = 6480 Megabits
   (which btw = 6.48 Gigabits) If it's 810 Megabits, then that's equal to
   (810/8) * 10**6 = 101.25 Megabytes. Either way, it doesn't add up to 770 or 
772...
   Just to clarify further, disc sizes are usually give in Megabytes. 
   The abbreviations are supposed to be: MB = Megabytes and Mb = Megabits
   but these are often confused.

3) Although physical memory and disk sizes are actually configured in binary
   increments, i.e. 2**10 = 1024, they are commonly rounded off to the nearest
   decimal multiple of K or M bits or bytes. But this is only a ROUNDOFF 
issue, 
   and generally the roundoff is in the downward direction, i.e.

10 Megs is really 1,024,000 
16 K is really 16,384 etc..

4) So where did all that disk space (810 - 770) actually go?  The key phrase 
here was:

"After formatting the drive..."

Yep, that's the byte eater... the formatting process automatically reserves 
alot of space for administering the file system, for spare tracks, etc.
typicallly 10% or more of your brand new disk! Bummer...

Gen

PS: I never introduced myself but I have a Thinkpad 755 something
which I know very little about, which is why I don't generally contribute
to these discussions... but I get alot out of them in terms of Thinkpad info,
so thanks, all!

-----------------------------------------------------
Genevieve Cerf, Ph.D. E.E.
Speech Recognition & Language Understanding Services
NYNEX Science & Technology
500 Westchester Avenue
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FAX: (914) 644-2211
gen@nynexst.com

> >>> From: "Arturo J. Morales" <art@aaRS.mit.edu>
> >>> Subject: Partition Problems w/ 810mb HD
> >>> 
> >>> I recently acquired an 810mb HD (IBM Brand) and proceeded to reformat and
> >>> partition it so that I could have a DOS/Windows/OS2 (FAT) partition and a Linux
> >>> partition.  After formating the Drive, (using MS-DOS 6.22) I only saw 770
> >>> megs...
> 
> Arturo,
> 
>     IBM's so-called "810mb" disk is, in fact, an 810-million-byte disk.
>     And 810,000,000 bytes = 772 mega-bytes.  So maybe your re-partitioning
>     worked correctly after all, and there's no "lost" space on your disk.
> 
>     It really stinks, the way some small-minded smart-ass marketing types
>     at IBM and some other companies have decided to deceptively re-interpret
>     "mb" to mean "million-byte" rather than "mega-byte", and introduce all
>     this unnecessary confusion.
> 
> Joseph
> 
> Joseph Manning / Computer Science / Vassar College / manning@cs.vassar.edu
>