prophetsdad said:I don't understand why my HD's aren't fully useable.
A 80Gb drive shows 76Gb useable, A 120Gb shows 111Gb useable, 160 =149, 200
= 186, etc.
What gives?
I have WinXP professional sp2, and AMD 2Ghtz system.
Any ideas?
TIA
John
JAD said:unformatted size Vs formatted
I don't understand why my HD's aren't fully useable.
A 80Gb drive shows 76Gb useable, A 120Gb shows 111Gb useable, 160 =149, 200
= 186, etc.
What gives?
I have WinXP professional sp2, and AMD 2Ghtz system.
Any ideas?
TIA
John
1GB = 1024MB as far as the rest of the world is concerned...prophetsdad said:I don't understand why my HD's aren't fully useable.
A 80Gb drive shows 76Gb useable, A 120Gb shows 111Gb useable, 160 =149, 200
= 186, etc.
What gives?
I have WinXP professional sp2, and AMD 2Ghtz system.
Any ideas?
TIA
John
Michael said:It is marketing and semantics really.
The HD makers say 1 GB = 1,000,000,000 bytes,
but we commonly say 1 GB = 1,073,741,824 bytes.
Timbertea said:1GB = 1024MB as far as the rest of the world is concerned...
But hard drive manufacturers state on the box that they measure 1GB =
1000MB.
DaveW said:The "80GB", "120GB", etc. ratings are the UNFORMATTED capacity of the
harddrives. They MUST be formatted before they can be used, and then you
get the "76GB", "111GB", etc. readings.
Everything's fine.
prophetsdad said:I don't understand why my HD's aren't fully useable.
A 80Gb drive shows 76Gb useable, A 120Gb shows 111Gb useable, 160 =149, 200
= 186, etc.
What gives?
I have WinXP professional sp2, and AMD 2Ghtz system.
Any ideas?
TIA
John
David Maynard said:You're going to get a lot of incorrect information so here's the reality of it.
Giga, Mega, Kilo, et al, are decimal prefixes but computers operate in binary and, to 'simplify' things, they've bastardized the
decimal prefixes into what I call 'decibinal' (to correctly note that it is not decimal nor binary but a strange 'combination'): a
pseudo binary nomenclature using not-quite-right decimal prefixes. (Because no one likes saying 1073741824 bytes and the poor
binary folks didn't have binary prefixes to use for shortening it so bastardizing the decimal ones seemed the 'quick and easy'
thing to do.)
I.E. the closest thing to a kilo, 10^3, in binary is 1024 (2^10) so even though it's not really a kilobyte they call it one
anyway. Same with Mega, 10^6. The nearest binary number is 1048576 (2^20). And for giga, 10^9, the nearest binary number is
1073741824 (2^30).
So you need to know which 'number system' is being used to know how the prefixes are being used: the correct decimal way or the
'decibinal' way.
Hard drive manufacturers use the decimal number system, just like everyone else in the (decimal) world, so "120 GB" means 120 x
10^9, just as one who took any reasonable math class would expect.
File Manager, however, reports things in 'decibinal' so GB means 1073741824 bytes and that means something reported in 'decibinal'
gigabytes will appear smaller than when reported in decimal GigaBytes even though they are talking about the same thing.
E.g. 120 Decimal GigaBytes will come out as 120/1.073741824 decibinal GigaBytes, or 111.76 (decibinal) GB (they tend to truncate
numbers rather than 'round up' so the 111.76 shows as 111GB).
So, 120GB = 111GB. Same size, same number of bytes.
It has nothing to do with 'formatting' or anything else.
Now, you can get the 'real' size by doing a properties on the drive from either My Computer or Windows Explorer. Right click on
the drive and select Properties. You'll see the *real* "Capacity" reported down to the byte, as on my 120GB drive "120,031,478,272
bytes" with the 'decibinal' size to the right, as on mine "111GB." Same drive, same size, same number of bytes, two ways of saying
it.
Btw, you can get the *real* size of any file by right clicking on it and selecting Properties too. The decimal size will be in ().
For example, this "Size: 47.6 MB" file on my system shows "47.6 MB (49,920,000 bytes)" in it's Properties and, to confirm the
math, 49,920,000 divided by 'decibinal' MB (1048576 byes) is 47.607421875 or, truncated, 47.6 MB. See? Same thing, same size, same
number of bytes, different way of saying it.
So, to summarize, all is perfectly fine with your drives. You got what you paid for, it's all there, no data is lost or missing,
no one is lying, there's no 'marketing gimmick', and everything is usable. You just need to know the math, which you now do.
David Maynard said:You're going to get a lot of incorrect information so here's the reality
of it.
Giga, Mega, Kilo, et al, are decimal prefixes but computers operate in
binary and, to 'simplify' things, they've bastardized the decimal prefixes
into what I call 'decibinal' (to correctly note that it is not decimal nor
binary but a strange 'combination'): a pseudo binary nomenclature using
not-quite-right decimal prefixes. (Because no one likes saying 1073741824
bytes and the poor binary folks didn't have binary prefixes to use for
shortening it so bastardizing the decimal ones seemed the 'quick and easy'
thing to do.)
I.E. the closest thing to a kilo, 10^3, in binary is 1024 (2^10) so even
though it's not really a kilobyte they call it one anyway. Same with Mega,
10^6. The nearest binary number is 1048576 (2^20). And for giga, 10^9, the
nearest binary number is 1073741824 (2^30).
So you need to know which 'number system' is being used to know how the
prefixes are being used: the correct decimal way or the 'decibinal' way.
Hard drive manufacturers use the decimal number system, just like everyone
else in the (decimal) world, so "120 GB" means 120 x 10^9, just as one who
took any reasonable math class would expect.
File Manager, however, reports things in 'decibinal' so GB means
1073741824 bytes and that means something reported in 'decibinal'
gigabytes will appear smaller than when reported in decimal GigaBytes even
though they are talking about the same thing.
E.g. 120 Decimal GigaBytes will come out as 120/1.073741824 decibinal
GigaBytes, or 111.76 (decibinal) GB (they tend to truncate numbers rather
than 'round up' so the 111.76 shows as 111GB).
So, 120GB = 111GB. Same size, same number of bytes.
It has nothing to do with 'formatting' or anything else.
Now, you can get the 'real' size by doing a properties on the drive from
either My Computer or Windows Explorer. Right click on the drive and
select Properties. You'll see the *real* "Capacity" reported down to the
byte, as on my 120GB drive "120,031,478,272 bytes" with the 'decibinal'
size to the right, as on mine "111GB." Same drive, same size, same number
of bytes, two ways of saying it.
Btw, you can get the *real* size of any file by right clicking on it and
selecting Properties too. The decimal size will be in (). For example,
this "Size: 47.6 MB" file on my system shows "47.6 MB (49,920,000 bytes)"
in it's Properties and, to confirm the math, 49,920,000 divided by
'decibinal' MB (1048576 byes) is 47.607421875 or, truncated, 47.6 MB. See?
Same thing, same size, same number of bytes, different way of saying it.
So, to summarize, all is perfectly fine with your drives. You got what you
paid for, it's all there, no data is lost or missing, no one is lying,
there's no 'marketing gimmick', and everything is usable. You just need to
know the math, which you now do.
PWY said:David:
Excellent post. The most thorough explanation I have seen on this
subject. Even though I am not the O. P. I have to say "thank you."
PWY
BobR said:P T wrote in message <[email protected]>...
Kind of like motorcycles?
You never get what they advertise.
A "750cc" might have 699 or 732 or whatever, but if it had 750, they'd
call it a 760 or an 800.
No. Motorcycles are rated at their 'over-bore size', so when you frag a
piston, bore it out, you can still race it in the (750cc) class!
<G>
Hard drive size difference is because no one can describe what a kilo is,
1024(computists) or 1000(the ad department(hey, look, it's bigger than it
really is!!)).
People are such suckers for advertising!!
"More money than
brains", I always say!
If you'll multiply the [heads * cylinders * (sectors_per_track * sector
size)],