OK, Math geniuses

I have a new Maxtor PATA hard drive mounted in an external enclosure. I understand that, when manufacturers advertise 160GB, they mean 160 x 1,000,000,000 bytes. That means the truth is 160,000,000,000 /1024/1024/1024 = 1.49 actual GB. However, this freshly formatted XP NTFS volume-- with no data written to it-- is being reported as free space 162,848,941,568 bytes or 152GB, with 69.2MB of used space. Can anyone clarify what I'm observing here?

 

Ok...not so sure this is a math problem...Let me see if I recall this correctly...I will try and find a link somewhere to explain this as well, but I'm not finding one to post at the moment. You have a hard disk that is rated as having 160GB of space available. Now, when you format that with the XP install it's going to create an MBR (master boot record), which expains the 64MB, and as for the missing 8128MB, they're dedicated to indexes. One at the begining of the drive, and one in the middle.
These greatly reduces search speeds on the disk, and the copy placed in the middle greatly reduces deletion errors. The thing is, this hard drive "map" gets larger and larger as the Gig's go up...and so when you format a 3 gig hard drive the missing amount is barely noticeable, a 160 gb, winds up losing 8 gigs.
I have 320 gigs in my PC and I can only use about 295 of those. It's kinda sucky when you need those extra few gigs, but you'll be glad for it when you're searching for that word document you made a 5 am last year .
I hope I answered your question, if I'm totally wrong, or off base let me know, and I'll do what I can to figure out the answer for ya!


Good luck,
koadmunki

 

Actually the 8GB differential is because the manufacturer considers a GB 1 billon bytes, and Windows considers a GB 1024 x 1024 x 1024 bytes.

The part that still puzzles me is why Windows is reporting more than 160,000,000,000 bytes free space-- that shouldn't be possible.

Also, there's typo in the OP-- should say 149GB, not 1.49.

 

The MBR is not 64MB. The boot sector is exactly 512KB. The way HD capacity is defined is different from the way memory capacity is defined. HD capacity is defined by powers of 1000, i.e. 1000=1K, 1000x1000=1M, 1000x1000x1000=1G, 1000x1000x1000x1000=1 Terrabyte. Memory capacity is defined by powers of 1024, i.e. 1024bytes=1K 1024x1024=1M, 1024x1024x1024=1G, 1024x1024x1024x1024=1 Terrabyte. So, using those definitions the HD has 3 Gig more space the the math allows. Unless this is one of those rare drives that defines its unformated storage capacity by powers of 1024. Thus the 152 Gigs of formated storage space.

 

I'm not sure we're all on the same wavelength here. I fully expected my 160GB drive to format out to 149GB under Windows. 1 kilobyte on a disk or in memory, to Windows, is 1024 bytes, and, similarly, MB and GB are powers of 1024. The question that remains is why is XP showing more free bytes than even that advertised by the manufacturer?

 

Format the drive as FAT32 then check the size, then format as NTFS and check the size.. The same?

 

Hmmm. If I were asked the difference between a drive formatted FAT or NTFS, I would probably cite cluster size for a given partition size, but I don't know if I would expect it to format out differently in total number of bytes, save for a bit of filesystem overhead.

 

The answer might be NTFS, it is a compressed file system, after all. But I don't know how much more drive space you gain with NTFS.

Oh, my reply was aimed more at koadmunki than you, I would have expected 149 Gig also, 152 is suprising.

 

I'm beginning to wonder if it might be related to the chipset of the external enclosure itself. Hopefully, it won't be something that comes back to haunt me after I get 160, er... 152, um... 149GB of data on it.

I had a thought, though-- I may just reformat as FAT32 to see what happens. I realized that if I want to hook it up to a PC that does not recognize NTFS volumes, I'll be out of luck.

 

Worth a try to see how much of a difference there is between FAT32 and NTFS.

 

Hmmm. Disk Management in XP will not allow me to format it anything other than NTFS.

 

Could use a 98 startup disk to format FAT32.

 

Reformatting it NTFS, I lost 68K free space, with no change in total bytes.

 

It's got to be the NTFS native file compression.

 

Mebbe so. I reviewed another NTFS drive in my system (secondary IDE channel), and found it's three partitions showed 122.1GB total space. It's a 120GB Maxtor drive.

 

Now that's interesting.

 

Think I'll stop worrying about this issue. My first HD was 10MB-- a GB here or there these days isn't worth losing sleep over. Now if I can only get it formatted FAT32 while it's still in the external USB enclosure...

 

OK, here is what I have managed to figure out XP can format FAT32 but has a 35-Gig limit. You would have to use another OS something like 98SE, but that has an 128-Gig limit.

I had 2 200-Gig USB external drives at work, both were FAT32, There has to be a way. Just haven't found it yet.

 

If you are are using Wndows XP you can convert the NTFS volume into FAT32 using the following command:
convert (drive_letter): /fs:fat32

 

No, you cannot convert from NTFS to Fat32 with any MS utility.

 

But, you can convert NTFS to FAT32 with partition magic.

 

Indeed.

 

Care to weigh in on the original question?

 

What is the model number of the hard drive?

 

Maxtor 160GB 7200RPM 8MB cache EIDE Ultra ATA/133
Model L01P160

 

http://keppanet.netfirms.com/keppanet/supports/harddisk.htm

The above link might explain a few things.

and

 

I do understand the difference between decimal GB and binary GB, really. However, if applying the above formula to the specs of the Maxtor drive in question, you get:

512 bytes per sector x 317632 cylinders x 16heads x 63 sectors = 163,928,604,672

Not far off from the 163,921,571,840 being reported for my drive.

So, I suppose, the answer is that, even if Maxtor advertises 160GB as being 160,000,000,000 bytes, on the same data sheet as the above specifications, it's not exactly true.

 

Ok, I was wrong. But you convert a FAT into an NTFS with this command. Replace the FAT32 with NTFS though.

oops