New MBP, Is This Normal?

[cms2]

I ordered an MBP with a 160 GB hard drive. When I look at my system profiler under Serial-ATA it says total capacity 149.1 GB. I know that some hard drive is taken up with the OS and whatnot, but that's separate; total available is 141.1. Why is the total capacity only 149? Shouldn't it be more like 160 with 151 available?

 

[aaronw1986]

No, all hard drives are this way. It's perfectly normal.

 

[varmit]

I ordered an MBP with a 160 GB hard drive. When I look at my system profiler under Serial-ATA it says total capacity 149.1 GB. I know that some hard drive is taken up with the OS and whatnot, but that's separate; total available is 141.1. Why is the total capacity only 149? Shouldn't it be more like 160 with 151 available?

Removed due to stupidity.

 

[Makosuke]

All OS's need to format the drive and install a File Allocation Table. Which is what is taken up the 11 Gigs of space.

NO.

This is almost completely wrong, and it's an unfortunate bit of old information that has refused to die.

The formatting information takes up a very, very small portion of the disk. What you're seeing is a side effect of the fact that all hard drive manufacturers define a Gigabyte as 1,000,000,000 bytes -- base ten. All OSes, however (Mac, Windows, Unix, and Linux at least, probably others as well) use a base-2 system. So 1KB is 1024 bytes, not 1000, 1MB is 1024KB, and 1GB is 1024MB.

Thing is, when it's only 1KB, that 24 is pretty small. But when you multiply it out, 1GB = 1024*1024*1024 = 1,073,741,824 bytes. Which is 1.073GB in hard drive manufacturer, base 10 GB.

So if you divide the 160GB (manufacturer) by that 1.073GB (OS), you get 149.1GB (actually a little less--your drive is probably a hair larger than 160GB, which is common).

Bottom line is, you are getting exactly what you should be--the OS just does the math differently. It's really, really stupid, and should have been fixed one way or the other a long time ago, but that's why on every single HD related advertising thing you'll see a little * pointing out that HD manufacturers calculate a GB as 10^9 bytes. Go have a look at the Tech Specs on the MacBook page at Apple's site.

RAM, interestingly, is actually done in base-2, OS style, so it's not an issue there.

There is actually a "corrected" notation now KiB (kibi-bytes), MiB, and GiB for the OS-style base-2 versions, but it's not very popular outside geeky circles so far.

Here's Western Digital Knowledge base article that may explain it better than I if you're not following:

http://wdc.custhelp.com/cgi-bin/wdc...XkgZHJpdmUgc2hvdyBzbWFsbGVy&p_li=&p_topview=1

 

[Neutral Gamer]

NO.

This is almost completely wrong, and it's an unfortunate bit of old information that has refused to die ...
...
...

Wow, that's a great reply Makosuke. Good explanation.

 

[Santa Rosa]

NO.

This is almost completely wrong, and it's an unfortunate bit of old information that has refused to die.

The formatting information takes up a very, very small portion of the disk. What you're seeing is a side effect of the fact that all hard drive manufacturers define a Gigabyte as 1,000,000,000 bytes -- base ten. All OSes, however (Mac, Windows, Unix, and Linux at least, probably others as well) use a base-2 system. So 1KB is 1024 bytes, not 1000, 1MB is 1024KB, and 1GB is 1024MB.

Thing is, when it's only 1KB, that 24 is pretty small. But when you multiply it out, 1GB = 1024*1024*1024 = 1,073,741,824 bytes. Which is 1.073GB in hard drive manufacturer, base 10 GB.

So if you divide the 160GB (manufacturer) by that 1.073GB (OS), you get 149.1GB (actually a little less--your drive is probably a hair larger than 160GB, which is common).

Bottom line is, you are getting exactly what you should be--the OS just does the math differently. It's really, really stupid, and should have been fixed one way or the other a long time ago, but that's why on every single HD related advertising thing you'll see a little * pointing out that HD manufacturers calculate a GB as 10^9 bytes. Go have a look at the Tech Specs on the MacBook page at Apple's site.

RAM, interestingly, is actually done in base-2, OS style, so it's not an issue there.

There is actually a "corrected" notation now KiB (kibi-bytes), MiB, and GiB for the OS-style base-2 versions, but it's not very popular outside geeky circles so far.

Here's Western Digital Knowledge base article that may explain it better than I if you're not following:

http://wdc.custhelp.com/cgi-bin/wdc...XkgZHJpdmUgc2hvdyBzbWFsbGVy&p_li=&p_topview=1

Well in, thats one that needs to be cleared up a lot.

 

[cms2]

thanks so much for all the great responses! This site and its great members never fail to impress!

 

[Apple Corps]

Makosuke - that is the type of educational response that is really helpful - Well Done

From the HOT part of California

 

[119576]

NO.

This is almost completely wrong, and it's an unfortunate bit of old information that has refused to die...

very well explained, Makosuke.