Meaning of NSProcessInfo physicalMemory value

Question

According to the NSProcessInfo docs, -physicalMemory returns the "amount of physical memory in bytes.". However, on my 32 GB iPhone 5, it returns 1065000960, which is only around 1 GB (1016 MB). What's up with that? Does it actually return the number of blocks or something? Could this be a bug in the API?

FWIW, I get the same value using sysctl().

You are confusing RAM (volatile memory) and disk (non-volatile storage). They're separate things. The value you're getting is the device's RAM size. — nobody, May 12 '14 at 21:50
He ment "RAM" and "ROM" i think and that's ok to call it Disk just to get it point :) — Dekel Maman, May 12 '14 at 21:52
@DekelMaman: That's a strange thing to say in a community full of pedants. He didn't mean ROM either. — Robert Harvey, May 12 '14 at 21:53
@RobertHarvey iPhones may not have disks, but they have separate RAM and file system interfaces, like most computers. I have 32 GB of storage, but only 1 GB of RAM. — theory, May 12 '14 at 21:54
Obviously they don't *literally* have spinning disks, but the flash storage can be thought of as an SSD (Solid State Disk). — nobody, May 12 '14 at 21:55
Hehehe stupid conversation :) anyway i think he got the idea — Dekel Maman, May 12 '14 at 21:55
It is a stupid conversation until one of your relatives comes up to you with a 3 1/2 inch floppy and asks you "Where do I put this hard disk?" — Robert Harvey, May 12 '14 at 21:56
Yes. So do I add my own answer to the effect that I'm confused, or will @AndrewMedico do it so I can accept? — theory, May 12 '14 at 21:56
@RobertHarvey Phones may not have hard disks, but they do have flash memory (non-volatile storage) which is treated exactly like a hard disk. — David Berry, May 12 '14 at 22:03
@David: Yes, I think we've already established that. But thanks for pointing it out again. — Robert Harvey, May 12 '14 at 22:04

score 4 · Accepted Answer · answered May 12 '14 at 21:58

4

The -physicalMemory method is returning the amount of RAM (volatile storage) present in the device, which for the iPhone 5 is 1GB.

The "32GB" figure quotes in the device model is non-volatile flash storage (think SSD), which is separate from RAM.

answered May 12 '14 at 21:58

nobody

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Meaning of NSProcessInfo physicalMemory value

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