Storage drive capacity in Mac OS X v10.0 through 10.5:
Storage drive manufacturers measure storage drive capacity using the decimal system (base 10), so 1 gigabyte (GB) is calculated as exactly 1,000,000,000 bytes. The capacity of the storage drive in your Mac, iPod, iPhone and other Apple hardware is measured using the decimal system. We set this out on our product packaging and on our website through the statement “1 GB = 1 billion bytes.”
Operating systems, including the operating system on your Mac, iPod, iPhone, or other electronic devices, use the binary system (base 2) of measurement. In binary, 1 GB is calculated as 1,073,741,824 bytes. This difference in how the decimal and binary numeral systems measure a GB is what causes a 4 GB storage drive to appear as 3.7 GB when detailed by an operating system, even though the storage drive still has 4 billion bytes, as reported. You will see this difference if you look at how your computer summarizes the capacity of the computer’s storage drive or of your iPod’s or iPhone’s storage drive when the device is connected to your computer. You will also see this difference in the “About” menu on your iPod or iPhone. The important point to understand is that the available storage capacity is the same no matter which system is used. Nothing is missing.
The storage drive in your Apple product, like all storage drives, uses some capacity for formatting, so actual capacity available for applications will be less. In addition, other factors, such as pre-installed systems or other software and media, will also use part of the available storage capacity on the drive.
Storage drive capacity in Mac OS X v10.6 and later:
In Mac OS X v10.6 Snow Leopard, storage capacity is displayed as per product specifications (base 10). A 200 GB drive show 200 GB capacity (for example, if you select the hard drive’s icon and choose Get Info from the Finder’s File menu, then look at the Capacity line). This means that, for example, if you upgrade from an earlier version of Mac OS X, your drive may show more capacity than in the earlier Mac OS X version.
The storage drive in your Apple product, like all storage drives, uses some capacity for formatting, so actual storage available for applications will be less. In addition, other factors, such as pre-installed systems or other software and media, will also use part of the available storage capacity on the drive.
Source: Apple Inc.
MacDailyNews Note: While the measurement has changed, so has the code. Snow Leopard is indeed smaller than Leopard regardless of the measurement system you choose.
[Thanks to MacDailyNews Reader “Shawn J.” for the heads up.]
Is this how apple is “reclaiming” disk space with Snow Leopard? I’m sure it’s not the only space-saving feature.
So the truth comes out. If this was a M$ trick, the mac fan boys would crap a brick.
Bits and nibbles and bytes. I’m confused.
http://en.wikipedia.org/wiki/Orders_of_magnitude_(data)
Is this how apple is “reclaiming” disk space with Snow Leopard? I’m sure it’s not the only space-saving feature.
No. Learn basic math. A change in measurement gains you precisely zero extra space.
It would be like switching from measuring from Fahrenheit to Celsius. The temperature doesn’t change, you’re just changing to a superior form of measuring.
Call me a traditionalist, but I don’t like it. I liked the old way (base 2) better.
@Rob, unless you know this first hand and for sure you should hold off on asking other members to learn something. Has Apple succumbed to it’s marketing department? Someone who has Snow Leopard installed who also did some measurements before and after please enlighten us. As part of this measurement please fill a folder with 10GB of data and then tell us if it is still reporting 10GB after the Upgrade. I would do this but Purolator shows my copy of SL has not been delivered and has a status of “Corrective Action” not sure what that means but I hope they correct it soon.
Idiots… The “capacity” of the drive does not change how much space is being occupied. Leopard does indeed take up significantly less space on the drive, regardless of what the Get Info window reports as the total capacity.
Bob R is right – or would be, if this were some trick intended to confuse or mis-inform users. We would (mostly) be in high dudgeon over the buffoonery. While I go along with pastrychef on this, I don’t see it as an effort to trick, fool or cheat anyone. If you have a car, you MUST know that your fuel gauge is – at BEST – advisory. Right? When GetInfo tells me I have used 211 GB of my 232 GB drive, my mental calculations say “90% full”, not “21 GB free”, and I KNOW I’m on dangerous territory if I go beyond “95% full” – ‘cuz I wuz an IT drone!
Since when is Celsius necessarily “Superior” to Fahrenheit? Metric is good, but Fahrenheit clearly has better granularity than Celsius.
Jeff, maybe you should pause to think for a moment. Maybe a very LOoooNG moment. Are you taller according to the metric tape measure on your right? Or the classic “American” tape measure on your left? The numbers to your left LOOK a little larger! Are they? Are they REALLY? In Feet and Yards you are “bigger” than you are in Meters … unless you have the vaguest clue about measurement.
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@Jeff
Rob correctly related the situation as described by Apple and documented by others who have installed pre-release copies of SL. By itself, the elimination of PPC code from the operating system will yield a significant reduction. At this point, it appears to me that it is more foolish to be overly skeptical and demand ‘proof’ of Rob’s restatement of published information. The basis of measurement can only be used in the manner you describe if the company is deceptive.
I have no doubt whatsoever that SL requires less installation space on the HDD than Leopard.
Says I’m over 20 GB lighter with Snow Leopard on a 250 GB drive so that isn’t just rounding.
Um, okay basic math.
Say I had a
100 GB hard drive in Leopard = 107 GB hard drive in SL
Now,
70 GB of data in Leopard = 74.9 GB of data in SL
The gain of space being:
30 GB free in Leopard =&= 32.1 GB free in SL.
A difference of = 2.1 GB freed up.
If people are seeing 7 GB to 15 GB (one reviewer) freed, it would seem that there’s a lot less code in Snow Leopard. Because as the drive is charted bigger, so will the data in your system be charted bigger.
Are my nerd creds giving out on me? Even if this is part of the Marketing Department’s 6 GB, it would seem that SL’s code is optimized and smaller…
Unless, of course, if you’re talking 320 GB hard drives…
Anyone seen the fine print on Apple’s page?
Thank you Apple! Now I no longer have to explain to noobs why their 250GB hard drive only reports 216GB or whatever. Now we just need the rest of the industry to get out of the dark ages. Binary units are an antiquated unit of measure that have no useful purpose in this day and age for the majority of computer users.
@jaundiced
Just because a degF is smaller than a degC (your “granularity”), that doesn’t make Fahrenheit better, either. The resolution and accuracy of a measurement is determined by the device, not the scale. Thermometers typically measure a thermal equilibrium of the device and the environment, anyway.
I do consider Celsius to be superior to Fahrenheit. I prefer a system with 0 as freezing and 100 as boiling. If you want to get technical, the Kelvin and Rankine scales could be considered superior to either because they reference absolute zero as 0 rather than -273.15 degC or -459.67 degF.
I truly wish that the U.S. would fully embrace the metric system (SI). We mix Watts and mm with BTU and lb-ft. But that would still leave time measured in seconds, minutes, hours… Nothing is perfect, I suppose.
Apple:
Snow Leopard takes up less than half the disk space of the previous version, freeing about 7GB for you.
Hmm, given the above,
100 GB hard drive in Leopard = 107 GB hard drive in SL
x GB OS in Leopard = x-7 GB OS in SL
Verdict:
On a 100 GB HD you should see on SL
+7 GB increase in HD space from smaller SL
+0 to 7 GB perceived increase in # from new metric (empty drives will seem to show 7 GB more free space; completely full drives will show 0 GB more free space.)
=> +7 to +15 GB increase in perceived HD space on a 100 GB system.
…actually sounds like what we’re hearing.
I have spent the majority of my life in the US, but find the inherent logic of the Celsius scale to be considerably more useful than the enhanced precision of the Fahrenheit scale.
To complete the hat trick:
Here’s what you should gain when you upgrade:
100 GB hd: 7 to 14 GB more free space.
200 GB hd: 7 to 21 GB more free space.
300 GB hd: 7 to 28 GB more free space.
* 7 GB is real gain of space; the rest is perceived gain because of the new metric.
@ jaundiced and @ pastrychef
> but Fahrenheit clearly has better granularity than Celsius.
> Call me a traditionalist, but I don’t like it. I liked the old way (base 2) better.
Nice to see some people with common sense around here, regarding the metric system. A system that artificially adheres to a system of 10’s is not better than old school measurement systems that evolved over centuries based on the needs of the “users.” Metric is better in the realm of the very small (nano scale) and very large (astronomical scale), but not in every day life where people actually need to measure things with cups and rulers (and thermometers).
And totally off topic…
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@Jeff
Here’s some remedial math for you:
1) Let’s say I have a 6 GB hard drive, and it contains two files, each 3 GB in size. So the drive is full. Follow so far?
2) Let’s say Apple randomly changes the way they measure size, and so my hard drive now magically reports as 12 GB in size.
3) If you failed 3rd grade math, you might be thinking: OMG, my HD went from 6GB to 12GB! I have 6 GB of new space! I can fit two more of these 3GB files on it!
4) You would be dead wrong, because each of the files also must be measured using the new system. Thus they each now take up 6 GB instead of 3 GB, and so your new 12 GB drive is still full.
Thus, as I said earlier: A change in measurement gains you precisely zero extra space.
QED.
This is how the storage people have ripped us off for years. I say we take back the binary system….Come on folks…let’s take it back!!!
just my $0.02
I have to say I seriously dislike this change. Computers operate on the binary (Base2) system. This is how they work and read data. Modifying how it reports file sizes and disk space to accommodate an inherently deceptive method of measuring drive capacity is simply wrong. What the industry needs to be doing is reporting drive capacities using Base2, rather than artificially making them seem larger using Base10. Using Base10 is a marketing scam, plain and simple.
Fat Basterd,
You are absolutely wrong. A disk drive that is specified as 250GB actually has 250,000,000,000 bytes. If the metric used was Base2, the space on that 250GB drive would have been reported as 232GB (in Base2 system). This is extremely confusing, since bytes don’t correlate with kilobytes, Megabytes and Gigabytes.
In other words, those 232GB are 238,418 MB, or 244,140,625 kb. To anyone but an übergeek, this makes absolutely no sense.
For people who have plenty of free space on their hard drive, it will be very exciting to check the available free space after upgrading. If you check before the upgrade and it shows 80GB free, after the upgrade, these 80GB of free space (previously reported using Base2) will now report as 86GB. That’s in addition to any space saving SL provides. Vast majority of people will be ignorant of the change of the metrics, and might be thrilled when they see the space saving greater than what they anticipated. In actuality, the saving wasn’t as great as the numbers implied.
Using Base10 may have been a marketing scam long ago (the Base10 number is higher than Base2 for the same capacity), but an average person only understands Base10 math, where a Gigabyte will equal exactly 1,000 Megabytes (and not 1,024 Megabytes).
To extend the argument a bit further (in order to highlight the confusion with Base2 system), let’s look at it this way. I’ll use the traditional decimal prefixes, as used across the metric system:
1b = 1 byte
1db = 1 deci-byte = 10 bytes
1 hb = 1 hecto-byte = 100 bytes
1 kb = 1 kilo-byte = 1,000 bytes; but no, under Base2, it’s 1,024 bytes (?????)
And we carry this on; under the (universally common) decimal system, 1Gb should be equivalent of 1,000 kB, or 1,000,000 b, but no; it’s 1,024 kb, or 1,048,576 bytes (and so on).
I would love to hear a convincing argument why should one kilo-byte represent 1,024 bytes, when one kilometre represents thousand metres, and one kilogram represents thousand grams, and one kiloVolt represents thousand Volts, and one kiloWatt represents thousand Watts (etc, etc, etc)…?