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From: J. J. Lodder on 31 Jul 2010 03:39
John <coffee(a)the.cafe.com> wrote:

> In the past, all the external HDs I've had, always shown the space
> available to be less than the HDs specs.

You misread the specs.
A 1 TB disk really contains (a little more than) 1,000,000,000,000
bytes.

> I have just finished setting
> up a Lacie D2 Quadra 1TB HD, after getting rid of the Windows software
> I have 999.3 GB available. What have they done different to the HD to
> achieve this.

Nothing changed in the way of HDs.
(except perhaps more explanation on the box)

Apple changed its way of reporting,
(starting 10.6)

Jan

From: Rowland McDonnell on 31 Jul 2010 04:43
David Empson <dempson(a)actrix.gen.nz> wrote:

> Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
>
> > Conor <conor(a)gmx.co.uk> wrote:
> >
> > > John wrote:
> > > > In the past, all the external HDs I've had, always shown the space
> > > > available to be less than the HDs specs. I have just finished setting up
> > > > a Lacie D2 Quadra 1TB HD, after getting rid of the Windows software I
> > > > have 999.3 GB available. What have they done different to the HD to
> > > > achieve this.
> > >
> > > Nothing.
> >
> > They have changed the way MacOS X reports disc space.
> >
> > MacOS X 10.6 shows size in multiples of a thousand rather than powers of
> > two, which is what the HD adverts use by way of a capacity spec.
> >
> > I /think/ this is a new thing for 10.6.
>
> It is. You have to watch out, though: 10.6 Finder reports capacities in
> powers of ten, but third party applications may still be usign powers of
> two, resulting in an apparent difference (7% out if the figures are
> measured in gigabytes).

But what's a gigabyte?

Don't forget that MS-DOS 1.44MB floppies are just like Mac 1.4MB
floppies - only the Mac capacity is measured in multiples of 1024 x
1024, while the MS-DOS capacity is measured in multiples of 1024 x 1000.

Honest.

Rowland.

--
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From: David Empson on 31 Jul 2010 08:28
Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:

> David Empson <dempson(a)actrix.gen.nz> wrote:
>
> > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
> >
> > > Conor <conor(a)gmx.co.uk> wrote:
> > >
> > > > John wrote:
> > > > > In the past, all the external HDs I've had, always shown the space
> > > > > available to be less than the HDs specs. I have just finished
> > > > > setting up a Lacie D2 Quadra 1TB HD, after getting rid of the
> > > > > Windows software I have 999.3 GB available. What have they done
> > > > > different to the HD to achieve this.
> > > >
> > > > Nothing.
> > >
> > > They have changed the way MacOS X reports disc space.
> > >
> > > MacOS X 10.6 shows size in multiples of a thousand rather than powers of
> > > two, which is what the HD adverts use by way of a capacity spec.
> > >
> > > I /think/ this is a new thing for 10.6.
> >
> > It is. You have to watch out, though: 10.6 Finder reports capacities in
> > powers of ten, but third party applications may still be usign powers of
> > two, resulting in an apparent difference (7% out if the figures are
> > measured in gigabytes).
>
> But what's a gigabyte?

According to Leopard's Finder (and earlier), it is 1073741824 bytes.

According to Snow Leopard's Finder, it is 1000000000 bytes.

Hence my comment about a 7% difference (actually 7.3741824%), depending
on whether you are talking about "power of ten" or "power of two"
gigabytes.

Terabytes are even worse: almost exactly 10% (1099511627776 vs
1000000000000).

Megabytes are almost 5%: 1048576 vs 1000000.

Kilobytes are about 2%: 1024 vs 1000.

> Don't forget that MS-DOS 1.44MB floppies are just like Mac 1.4MB
> floppies - only the Mac capacity is measured in multiples of 1024 x
> 1024, while the MS-DOS capacity is measured in multiples of 1024 x 1000.
>
> Honest.

Yes, I know all that.

I happen to think the use of power-of-ten capacities was misleading,
because the sector sizes and hence units of allocation are actually
powers of two.

--
David Empson
dempson(a)actrix.gen.nz
From: Richard Kettlewell on 31 Jul 2010 08:49
dempson(a)actrix.gen.nz (David Empson) writes:
> Yes, I know all that.
>
> I happen to think the use of power-of-ten capacities was misleading,
> because the sector sizes and hence units of allocation are actually
> powers of two.

We measure RAM in binary units, leading to the somewhat curious effect
that a megabyte in RAM won't fit into a disk vendor's short megabyte.

RAM vendors don't seem to feel any need to advertize in the smaller
units, it's a pity disk vendors didn't take a lesson from them.

--
http://www.greenend.org.uk/rjk/
From: J. J. Lodder on 31 Jul 2010 09:52
David Empson <dempson(a)actrix.gen.nz> wrote:

> Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
>
> > David Empson <dempson(a)actrix.gen.nz> wrote:
> >
> > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
> > >
> > > > Conor <conor(a)gmx.co.uk> wrote:
> > > >
> > > > > John wrote:
> > > > > > In the past, all the external HDs I've had, always shown the space
> > > > > > available to be less than the HDs specs. I have just finished
> > > > > > setting up a Lacie D2 Quadra 1TB HD, after getting rid of the
> > > > > > Windows software I have 999.3 GB available. What have they done
> > > > > > different to the HD to achieve this.
> > > > >
> > > > > Nothing.
> > > >
> > > > They have changed the way MacOS X reports disc space.
> > > >
> > > > MacOS X 10.6 shows size in multiples of a thousand rather than powers of
> > > > two, which is what the HD adverts use by way of a capacity spec.
> > > >
> > > > I /think/ this is a new thing for 10.6.
> > >
> > > It is. You have to watch out, though: 10.6 Finder reports capacities in
> > > powers of ten, but third party applications may still be usign powers of
> > > two, resulting in an apparent difference (7% out if the figures are
> > > measured in gigabytes).
> >
> > But what's a gigabyte?
>
> According to Leopard's Finder (and earlier), it is 1073741824 bytes.
>
> According to Snow Leopard's Finder, it is 1000000000 bytes.
>
> Hence my comment about a 7% difference (actually 7.3741824%), depending
> on whether you are talking about "power of ten" or "power of two"
> gigabytes.
>
> Terabytes are even worse: almost exactly 10% (1099511627776 vs
> 1000000000000).
>
> Megabytes are almost 5%: 1048576 vs 1000000.
>
> Kilobytes are about 2%: 1024 vs 1000.

There is no excuse for the muddle anymore.
The standard has been set.
GB MB TB etc for powers of ten (in keeping with general usage)
GiB, TiB, MiB, ect for powers of two.

Jan
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