In article <bPVDi.1802$s06.267@trnddc04>,
pmBERMUDA_SHORTScook@gte.net says...
>
> "krw" <krw@att.bizzzz> wrote in message
> news:MPG.214923997e05043198a9a3@news.individual.net...
> > In article <Xns99A278AEBD96Bipostthereforeiam@69.28.186.120>,
> > no@spam.com says...
> > > Terry <kilowatt@charter.net> wrote in
> > > news:1188955984.041565.117070@o80g2000hse.googlegroups.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