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krw

In article bPVDi.1802$s06.267@trnddc04,
says...

"krw" wrote in message
t...
In article ,
says...
Terry wrote in
oups.com:

They are just padding the numbers. It is a good thing she found this
information before she packed it up and took it back for nothing.

While I agree that the advertising is misleading it is common practice
to report installed memory as opposed to 'usable' memory.

Likewise for hard disks, where the size is often reported as
unformatted,
which is completely useless, of course. Then depending on what file
system it is formatted in (NTFS for example) you get a big chunk devoted
to the file system and not available for your stuff.

No, there is no difference between formatted and unformatted disk
size (unformatted disk drives don't exist in the wild). The issue is
that disks are sold by the decimal megabyte (10^6 bytes) rather than
binary "megabytes" (2^16 bytes) as memory is.

No you're wrong again. Disks are indeed just blank platters until formatted
which is why when you buy a hard drive it does not say "for PCs only."

Wrong. Hard disk are formatted at the factory. They're non-
functional without formatting. I haven't seen a disk marked "for PCs
only" since the year of the flood.

You
can take any SCSI drive for example and use it in a PC, MAC, Unix, VMS, IBM,
Cray, Unisys or whatever - all sharing the same interface, all incompatible
file systems and drive formats and logical architecture. Depending on the
OS and the file system, there is loss due to allocation table overhead and
also due to the fact that under NTFS and most others such as FAT and FAT32
there are the same number of sectors per track.

File system formatting. The OS can install its own filesystem.
It *cannot* format a modern drive. Without formatting the hardware
has no clue how to access the drive - no index marks, no track marks,
no clocks, nothing.

Very few OSs actually use
variable sector mapping. Oddly enough the old Commodore 64 was one. You
fit the same number of sectors on a center track as an edge track therefore
you lose more space at the outside of the disk. Picture a pie cut in
wedges.

No, modern disk have more sectors on the outside tracks (see: "zoned
recording"). The sectors are the same sized though. Variable
sectors aren't worth the overhead, given the size of disks these
days.

Originally, disk drives were actually drums for this very reason -
far easier to work with and the only way they could get any respectable
capacity - and where we get terms like cylinder from. The next factor is
the cluster size itself. Smaller clusters require more management but are
less wasteful. Larger clusters waste more space but are better for ECC and
performance.

Meaningless to the discussion...

For the sake of this discussion, NTFS has about a 10% file overhead. A 160
GB drive will format out to about 145-148 GB. The rest is just wasted space
and table space. This is a general rule of thumb as NTFS chooses the
cluster size based on the partition size. You can however, change that.
You can run NTFS with different cluster sizes but it introduces other
issues. As disk formats go, NTFS is one of the more wasteful. But it
really does not matter since the cost per gig is so incredibly low.

Also meaningless...

Class dismissed.

Demand a tuition refund.

--
Keith