8100 hard drive

Hello,

I picked up a 9.1GB external hard drive at a thrift shop. According to
Disk Manager Mac, it has a "Mac OS extended" format. My Power Macintosh
8100/100 only sees 8.4GB of space. Any ideas why it does not see the full
capacity of the drive? The drive is a Seagate ST39140N.

Thanks

az268nospam.RemoveThis@chebucto.ns.ca (Jonathan Adams) writes:

 > I picked up a 9.1GB external hard drive at a thrift shop. According to
 > Disk Manager Mac, it has a "Mac OS extended" format. My Power Macintosh
 > 8100/100 only sees 8.4GB of space. Any ideas why it does not see the full
 > capacity of the drive? The drive is a Seagate ST39140N.

This doesn't really have anything to do with macs. It is probably
(almost certainly) on the FAQ list in whatever the newsgroup about
hard drives is.

Your Mac no doubt means 2**30 bytes when it says 1Gb. Typically,
1k = 2**10, 1m = 2**20, 1g = 2*830, etc. These are faitly "natural"
units for binary addressed hardware. Thus 1k is exactly 1024,
1m is approx 1.05 million and 1g is approx 1.08 billion.

Hard drive manufacturers like to use the decimal (and traditional)
definitions where 1k = 1000, 1m = 1 million, and 1g = 1 billion.
Mostly they do this because it makes the numbers look bigger.
And they can claim it is not false advertizing - after all, that
*IS* the traditional definition of 1g. It's just that the traditional
decimal numbers don't match well with actual computer architecture.

So your drive advertized as 9.1gb presumably has about 9.1 billion bytes.
Divide that by approx 1.08 to get units of 1gb with the "binary"
definition of 1gb, and I get.. let's see... yep... 8.4 gb. It is the
same number of bytes on the drive - just different definitions of
what 1gb means.

--
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email: my first.last at org.domain | experience comes from bad judgment.
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