127 gig barrier

[thefly]

Just wondering if someone could offer the mathmatical reason behind the 127 gig harddrive barrier.

I'm sure it must have something to do with a maximum addressing limitation of some sort.

Anyone know the answer?

 

[David]

I think it is to do with the limits of FAT32 ie. 32k blocks, maximum number of blocks - 2^32 - something like that.

yes, I think that works out.

 

[thefly]

no. That is not correct. The file allocation table has nothing to do with the hard drives physical limitation.

fat 32 Supports up to 2 terabytes in size: Compared to 2GB of FAT16, 1000 times more.

Ntfs supports even more.

I think the 127 gig limit has to do with enhanced bios translation modes.

Remember the 504 meg limitation and then the 8 gig limitation after that?

It must have something to do with the bios and it's limitations to addressing the size of the drive.

But i'm not sure.

 

[David]

no. That is not correct. The file allocation table has nothing to do with the hard drives physical limitation.

fat 32 Supports up to 2 terabytes in size: Compared to 2GB of FAT16, 1000 times more.

Ntfs supports even more.

I think the 127 gig limit has to do with enhanced bios translation modes.

Remember the 504 meg limitation and then the 8 gig limitation after that?

It must have something to do with the bios and it's limitations to addressing the size of the drive.

But i'm not sure.

Aahhhh!
C/H/S? I think I know what you are on about...

 

[thefly]

ya. Hmmm.

Digger where are ya?

 

[Maddman]

"The size limit is an artifact of the original ATA design, which uses 28 bit
addressing for the sectors on a drive. Two to the power of 28 is
268,435,456; at 512 bytes of data per sector, that's 137,438,953,472 bytes,
maximum. You can't have any more sectors on an old-style ATA drive. That works out to 128 GB on thenose almost.

The new standard that maxtor and other companies are using is 48-bit addressing for the sectors on a drive, giving more than 144 petabytes (144,000,000 gigabytes) of storage

 

[thefly]

Great! thanks madman.

ultra ata 133 is the new 48 bit format? I don't think seagate or ibm is following this are they?

 

[Diggrr]

Huh, I would have thought it was getting to a physical size restriction of not being able to put data tracks too close together for resolution reasons.
Much like CD couldn't jump to DVD until a mass produceable laser was available to read the much denser resolution that a DVD has.

 

[FerrariF50]

I like that new Maxtor 160Gb drive... a little pricey..

 

[Maddman]

Huh, I would have thought it was getting to a physical size restriction of not being able to put data tracks too close together for resolution reasons.
Much like CD couldn't jump to DVD until a mass produceable laser was available to read the much denser resolution that a DVD has.

That is factored in but IBM just came up with a way to realy pack in the data. the 144 petabytes is more theoretical then actual. It just gives them lots of headroom to work with.

 

[Diggrr]

Yeah, I saw the news conference IBM had on TechTv one night. I usually expect new tech to reach us by the next generation (people generations, not computer generations). For example, there's a lot of really cool stuff from Comdex and such that I can never find in the real world...I just expect it to be released at a reasonable price by the time my kids drive.

Pessimists' are never dissapointed, only pleasantly surprised.

 

[David]

Great! thanks madman.

ultra ata 133 is the new 48 bit format? I don't think seagate or ibm is following this are they?

Ultra ATA 133 isn't the new standard - there is a different on being pursued I think