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- Initialize vs. Format a HD
April 23, 2014, 1:50 pm
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Re: Initialize vs. Format a HD
Not exactly. It's a non technical term that can either mean erasing
what's on the drive (using something like dd), or it can mean running
a "low level format" https://en.wikipedia.org/wiki/Disk_formatting where
not only is the data erased, but the hard drive controller can change
things like the interleave value.
Formatting a partition within a hard drive does not erase other partitions,
or the mbr.
Changing the partition table between dos style and gpt will make all
existing partitions "invisible", but will not actually erase the data
in those partitions.
Regards, Dave Hodgins
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Re: Initialize vs. Format a HD
Initialize means to install the MBR sector 0 (512 bytes).
When a drive is new, there might be a block of zeros in
the first sector of the drive. Windows wants to write
a bit of information in there, which will include signature
bytes near the end of the sector. That's how Windows knows
what partitioning type is present.
Modern OSes can use GPT or MBR. GPT allows the seamless usage
of much larger drives (>2TB). A GPT drive still includes a
"protective MBR" and the partition table in the MBR is a hint
that a GPT is present in that case.
So initialize, to me, means putting that first basic bit of
info at the front of the disk. If a disk is completely blank,
and you enter Disk Management, Windows may pester you to define
some sort of representation there. It may want you to
choose Basic or Dynamic Disk (use Basic). If partitioning,
it'll talk about GPT or MBR. Use MBR if the disk is small.
GPT is more of a nuisance, without good tools, and is
reserved for the owners of recent-model computers (at
least, if you want to boot from it).
Format has an old definition, and a new definition.
In the old days, we'd refer to "low level format". That might
define the pattern of sectors on the drive. The drive had
a separate servo surface, which tells the heads where they are.
Because of that, the other heads could write sector headers
and sector bodies, in a manner of "soft sectoring". The low level
format then, meant magnetically defining the entire contents
of N-1 surfaces. The remaining surface, with servo contents,
was not touched. Users really had the sensation of "erasing
everything" with such a design. A separate servo surface
(the bottom of one platter) became impractical when the
density of the disks kept going up and up. And they got
rid of that design concept, and also the notion of
a true "low level format".
Modern drives use embedded servo. Sector numbering is stored
on each track, in between the data areas. The drive always
knows where it is. You can't rewrite the servo wedges.
There is no longer the idea of "low level format", which
writes entire surfaces. So instead of "format", now
you're just re-writing the data portion in each sector.
It's more of an "erase" operation than anything else.
It's no different, than any other write operation you might
do in Windows. And as such, it loses any special status
it used to have.
That would be at the drive level.
If you're in Disk Management, you right click on a partition
and select "Format" there - that writes initial file system
structures. Like perhaps 63 sectors of file system headers,
an empty MFT (Master File Table). That basically makes
the old files "go away", because they lose their mapping
when a new MFT is created (and overwrites any old MFT).
That's why Disk Management asks you if you really want
to do this - because formatting removed the file mapping.
So that's formatting a partition - at a minimum, it
refreshes the file system headers and metadata, and
starts things from scratch. All the old files on that
partition, are lost instantly when you do that. Only
format the things you no longer need.
Format (of a partition) has "quick" and "long" options.
The "long" option visits all the sectors, and takes longer.
That's about all I know about it, without looking it up :-)
I always use "Quick" when I format a partition, as I'm
always in such a damn hurry :-)