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rMBP SSD Missing Space
- Thread starter jlin615
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Interesting, I wonder if there was fine print on the packaging. Going back to my 600cc motorcycle really only being 599cc.
- Yes, I'm sure. No, I can't provide a link, but I can prove it to you:
Take a look at all your hard drives on your Windows PCs, and look at how many bytes their partitions have. If you divide that number by 1000 four times (i.e. x/1000/1000/1000/1000) you'll get almost exactly the same amount of GBs they were advertised to have by the manufacturer. If you, instead, divide the number by 1024 four times, you'll get the same amount of GBs that Windows is reporting.
This means that a 500 GB drive will show up as 465 GB under windows, a 256 GB drive will show up as 238 GB, and so on...
- Usually, there is.
Have you really been working in IT for several years without being aware of this?
Actually even the computer I'm replacing my Dell Dimension (2005) has a listed 250GB HDD and has a capacity of 234GB when shipped.
I am aware that you don't get exactly what it's marketed as, as for I've never seen anyone compare a GB to 1000MB. I've heard people say a GB is "about" 1000MB, knowing it's 1024.
I plugged in my Hitachi 80GB, windows is reporting 74.53 available.
Disk management says it's 76,317MB and properties says 80,024,170,496 bytes.
I plugged in my Hitachi 80GB, windows is reporting 74.53 available.
Disk management says it's 76,317MB and properties says 80,024,170,496 bytes.
Read the link I posted. It's quite common for hardware companies to state capacity as 1GB = 1000MB, rather than 1GB = 1024MB.
- That doesn't make sense, though, since OS X uses the 1000 MB to a GB system, not the 1024 MB to a GB system.
Thanks, that's a good link. Yet I still don't see what people are complaining about though, it's small percentages of space. The funny thing is both myself and JTToft have the same drive series and capacities yet we see completely different sizes. I am not complaining about the size though, I got a 256 and didn't expect to see 256 because I know you formatting uses space.
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Since I have my 830 in a windows machine and JTToft has his in OSX that would explain the differences we see. So some manufacturers and Apple is misrepresenting, and Microsoft is doing it right. Either way, I still don't see the big deal, we are post 4GB hard drives and storage is so cheap, I don't see the issue with nitpicking.
- No, we actually see the exact same capacity. The difference is only in the way Gigabytes are calculated. If we look at Bytes, I'll bet you anything our drives are exactly the same or very close to it.
For fun, here's my capacity in Bytes (the whole drive, not my partition): 256.060.514.304 bytes.
What's yours?
By the way: formatting uses nowhere near that much space. The difference you see on your machine IS because of the calculation of Gigabytes.
Are you smoking crack? Did you read my posts?
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Older versions of OS X, as well as Windows and most other operating systems, count hard disks by gibibytes instead of gigabytes, while OS X reports hard disks using gigabytes.I have a brand new 256GB samsung SSD sitting on my desk right now that I just got yesterday. I haven't put anything on it yet, but there is only 238.47GB available. That's 17.53GB wasted on formatting. Maybe I should sue samsung for selling me a 238.47GB drive.
It just so happens that 238.47 gibibytes is almost exactly 256 gigabytes: http://www.wolframalpha.com/input/?i=238.47+gibibytes+to+gigabytes.
The Samsung 830 is advertising 256 GIGABYTES which it has. The Apple SSD is advertising 768 GIGABYTES while it only has 750.
If you put the Apple SSD in a Windows computer (or simply check Boot Camp), I absolutely guarantee you Windows will say it has 232.8 GiB.
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1. OS X reports the more "optimistic" value, gigabytes, not gibibytes unlike Windows and most other OSes.
2. Hard drives are generally advertised in GIGABYTES because historically magnetic media has been manufactured in base 10 units (1000 bytes = 1 KB) while flash memory has been manufactured in base 2 units (1024 bytes = 1 KiB). However, SSD manufacturers have taken advantage of the difference to cut about 7% from SSDs for overprovisioning - a 512 GiB SSD will only have 512 GB available. This is why most hard drives and SSDs sold commercially are advertised correctly - the manufacturers make it clear that you're getting gigabytes and not gibibytes and that 1 GB = 1 billion bytes.
3. OS X uses the manufacturer advertised version of storage. Disk Utility will report a 480 GB SSD as having 480 gigabytes, a 500 GB Seagate hard drive as having 500 gigabytes, and a 750 GB Hitachi hard drive as having 750 gigabytes. Disk Utility reports 512 GB available on pretty much every third-party SSD advertised as 512 GB. Here's a screenshot of a Vertex 4 512 GB compared to a "512 GB" Apple SSD. The Vertex 4 was advertised properly, the Apple SSD was not.
4. OS X says the unformatted capacity is 250, 500, and 750 GB respectively for the 256, 512, and 768 GB flash storage modules in the rMBP - as I explained above, there is no amount of extra formatting or 1000 vs 1024 math that can account for this difference. The extra 18 GB on the top end drive can be a lot. You can fit two whole OS X installs on to that, plus a game, a movie, or a bunch of music. And with Apple charging $2 per gigabyte for storage, that's at least $36 down the drain.
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You guys are all being condescending for no reason.
As of Snow Leopard, OS X treats 1GB as 1000MB and 1MB as 1000KB. So a 512GB HDD should appear as 512GB to OSX with 512 billion bytes. However, with the SSDs, Apple seems to sell us short by about 2.5%. If I were to boot into windows, this drive would report itself as 465GB - not 512 or 500. So Apple's definitely short changing us a bit.
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Click for full size.
If I were to buy a 512GB SSD from any other vendor and plug it in, it would report itself as 512GB.
As of Snow Leopard, OS X treats 1GB as 1000MB and 1MB as 1000KB. So a 512GB HDD should appear as 512GB to OSX with 512 billion bytes. However, with the SSDs, Apple seems to sell us short by about 2.5%. If I were to boot into windows, this drive would report itself as 465GB - not 512 or 500. So Apple's definitely short changing us a bit.
Click for full size.
If I were to buy a 512GB SSD from any other vendor and plug it in, it would report itself as 512GB.
On the contrary, the 1000 vs 1024 math exactly accounts for the difference:
256,000,000 / 1024 = 250
512,000,000 / 1024 = 500
768,000,000 / 1024 = 750
Just because it accounts for the difference doesn't mean anything. As has been explained by a number of people, OSX treats 1KB as 1000B, 1MB as 1000KB, 1GB as 1000MB, and 1TB as 1000GB, while every other OS multiples by 1024 at each step. All you've proven with your math is there's a 2.4% discrepancy between advertised size and reported size. As you can see from my photo in my previous post, the drive only has 500,277,790,720 bytes that are addressable. When dealing at the level of bytes, there's no fuzzy 1000/1024 math. So we're definitely missing out on some space.
If you were to plug in any other HDD/SDD that's advertised as 500GB, it would report itself as 500GB to OSX.
Then how come I can plug in any other 512GB SSD and see 512GB?
Fact of the matter is, Apple's calculations are not consistent with the rest of the industry. If you buy a 512GB SSD directly from Samsung or whoever, you will get ~512,000,000,000 addressable bytes. Actual NAND capacity will be around 524GB, with the extra space mostly going to wear leveling. Based on Apple's current marketing, they'd market that drive as 524GB. But no one else in the industry does.
What are the units on those figures?
Your math is just wrong.
768 gigabytes = 715.3 gibibytes, not 750 gibibytes. OS X reports in gigabytes anyway.
Then Apple itself admits that wear-leveling blocks and bad blocks are actually counted - it's completely disingenuous to include wear-leveling space in your advertising and no other drive vendor does this. It's like including 256 GB of bad unaccessible flash in a 512 GB SSD and calling it a 512 GB SSD because it has 512 GB total, or including the cache RAM in an SSD in the capacity figure.
For one thing, plugging in any other SSD doesn't include a recovery partition, among other things.
My math is irrefutable and 100% accurate. You can't successfully argue with the math that I posted. I said nothing about gibibytes or gigabytes in my post. Read it again:
Do you see a single unit of measurement indicated?
You don't understand anything that's been said in this thread, do you? We're talking about the UNFORMATTED CAPACITY REPORTED IN DISK UTILITY, which INCLUDES all the space used up by recovery partitions and partition tables. We aren't talking about the size of the Macintosh HD partition. Besides, the formatting on a modern OS X boot drive takes up less than 1 GB.
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I'm talking about the full drive capacity - the extra partitions are not deducted at that point.
Besides, EFI partition and recovery partition take a miniscule amount of space.
Code:
APPLE SSD SM512E:
Capacity: 500.28 GB (500,277,790,720 bytes)
Model: APPLE SSD SM512E
Revision: CXM09A1Q
Serial Number: S0VMNYAC700889
Native Command Queuing: Yes
Queue Depth: 32
Removable Media: No
Detachable Drive: No
BSD Name: disk0
Medium Type: Solid State
TRIM Support: Yes
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Verified
Volumes:
disk0s1:
Capacity: 209.7 MB (209,715,200 bytes)
BSD Name: disk0s1
Content: EFI
Macintosh HD:
Capacity: 400 GB (400,000,000,000 bytes)
Available: 304.48 GB (304,475,983,872 bytes)
Writable: Yes
File System: Journaled HFS+
BSD Name: disk0s2
Mount Point: /
Content: Apple_HFS
Volume UUID: 63E66DE7-F9B0-3D7E-A9B2-BFCEE81DD8E1
Recovery HD:
Capacity: 650 MB (650,006,528 bytes)
BSD Name: disk0s3
Content: Apple_Boot
Volume UUID: A67B864C-7F13-353B-B5A8-AECCA3DC892C
Macintosh HD 2:
Capacity: 99.28 GB (99,283,812,352 bytes)
Available: 99.07 GB (99,069,898,752 bytes)
Writable: Yes
File System: Journaled HFS+
BSD Name: disk0s4
Mount Point: /Volumes/Macintosh HD 2
Content: Apple_HFS
Volume UUID: 554835A0-8A86-35AD-B5CA-8743121773AETwo things that system profile excerpt shows you: Firstly, the EFI partition and recovery partition take about 1GB altogether - not 6-18GB. Second: their space isn't free - they're deducting from the 500B the drive reports itself as, leaving 499B for everything else.
You will also find that if you get a 128GB SSD from apple (in a MBA for example), it will report itself as 120GB - not 125 (which is what your 1000/1024 math would lead you to believe). So Apple is just short changing all of its SSD customers however you slice it.
All right, those equations are correct, but can you actually explain what they're supposed to mean? They're meaningless without units. Let me clarify: your math is incorrect at proving anything you're trying to say.
I'm posting what Apple reports. Nothing more. This whole rant is completely pointless. You aren't going to change a single thing by complaining in this forum about what Apple states regarding capacity. If it twists you out of shape so much, go DO something about it. File a lawsuit. Boycott Apple products. Submit feedback to Apple. This is a completely trivial issue and it's childish to throw a tantrum about it. Get over it!
It most likely is due to overprovisioning, but Apple should not include overprovisioning in its advertising. Look at Sandforce drives - are any of them advertised as 512 GB, even though they have 512 GiB of flash on them? No, they're advertised as 480 GB because they use an extra 32 GB for overprovisioning/RAISE.
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You've not understood a single thing we've said, putting up bogus math to prove your points which aren't even true, and you finally capitulate by saying "but it doesn't matter anyway." Look who's being childish. Well, it matters to some people.