XP Partition size

[formerprof]

I just performed a clean reinstall of WinXP -- booted from the XP CD,
repartitioned and reformatted (NTFS) the disk. The repartition program would
not let me use the entire disk -- 6 or 8 mb of a 70 GB disk were left out
of the partition as free space. Why does XP do that? If I use Partition
Magic to reclaim the extra space what damage will I do?

Thanks to all.

formerprof
(e-mail address removed)

 

[Wislu Plethora]

-----Original Message-----
I just performed a clean reinstall of WinXP -- booted from the XP CD,
repartitioned and reformatted (NTFS) the disk. The repartition program would
not let me use the entire disk -- 6 or 8 mb of a 70 GB disk were left out
of the partition as free space. Why does XP do that? If I use Partition
Magic to reclaim the extra space what damage will I do?

Thanks to all.

formerprof
(e-mail address removed)


.

Why are you concerned about 1/100 of 1% of your drive
space?

 

[formerprof]

Why are you concerned about 1/100 of 1% of your drive
space?

Curiousity. Do you have an answer? Why waste bandwidth and time impugning
the question?

 

[formerprof]

Many thanks for your help -- that's very clear. All good wishes.


formerprof
(e-mail address removed)

 

[Wislu Plethora]

-----Original Message-----


Curiousity. Do you have an answer? Why waste bandwidth and time impugning
the question?

I wasn't impugning the question, I was impugning the
questioner. You post wanting to know if your data will be
threatened if you use Partition Magic to recover a tiny,
insignificant sliver of disk space and *I'm* wasting
bandwidth???

 

[formerprof]

Was that with Partition Magic?


formerprof
(e-mail address removed)

 

[Alex Nichol]

I just performed a clean reinstall of WinXP -- booted from the XP CD,
repartitioned and reformatted (NTFS) the disk. The repartition program would
not let me use the entire disk -- 6 or 8 mb of a 70 GB disk were left out
of the partition as free space.

The very first sector of a disk is reserved for its Master Boot Record
and Partition tables. As Partitions are made to be aligned on Cylinder
bounds (and don't try to make them different) the rest of the first
cylinder is left unused, usually just under 8 MB.

 

[Steve N.]

formerprof wrote:




The very first sector of a disk is reserved for its Master Boot Record
and Partition tables. As Partitions are made to be aligned on Cylinder
bounds (and don't try to make them different) the rest of the first
cylinder is left unused, usually just under 8 MB.

Sorry Alex, but this is incorrect.

Partitions are defined by blocks, not cylinders.

The approx. 8MB of unpartitioned disk space is there because XP Pro
installation reserves it for converting a Basic disk to a Dynamic disk.

Steve

 

[Bob Lawn]

Sorry Alex, but this is incorrect.

Partitions are defined by blocks, not cylinders.

what sort of blocks would these be?
With some Un*x OS's you can use sectors, cylinders and even megabytes; can't
think of any MS OS which didn't use plain ol' megabytes.

The approx. 8MB of unpartitioned disk space is there because XP Pro
installation reserves it for converting a Basic disk to a Dynamic disk.

I recently wanted to convert a 50Gb disk from basic to dynamic and it only
wanted 1 megabyte (which i didn't have).

Partitions are aligned to cylinder boundaries, so if the first cylinder
contains 1 or more used sectors, the first actual partition has to start at
the beginning of the 2nd cylinder, thus leaving the rest of the first
cylinder unused. Partitions also get rounded up (and down?) to the closest
cylinder boundary.

Not so?

Steve

bob

 

[Alex Nichol]

Sorry Alex, but this is incorrect.

Partitions are defined by blocks, not cylinders.

The approx. 8MB of unpartitioned disk space is there because XP Pro
installation reserves it for converting a Basic disk to a Dynamic disk.

They are defined by blocks (sectors) , but all partitioning software
aligns on cylinder boundaries - in LBA treating these as 256x64 sectors
or 8MB. The bit of space left is convenient for dynamic disk to use, as
also for example for the micro partition used by BootIT NG; but it is
the cylinder orientation that causes its presence. And you will find
that slack present if you create partitions with say Win98 FDISK, a
system that has no knowledge of dynamic disk

 

[Steve N.]

Steve N. wrote:




They are defined by blocks (sectors) , but all partitioning software
aligns on cylinder boundaries - in LBA treating these as 256x64 sectors
or 8MB. The bit of space left is convenient for dynamic disk to use, as
also for example for the micro partition used by BootIT NG; but it is
the cylinder orientation that causes its presence. And you will find
that slack present if you create partitions with say Win98 FDISK, a
system that has no knowledge of dynamic disk

Then please explain this drive geometry basics:

Number of cylinders
Number of blocks per cylinder
Number of sectors per block

Steve

 

[Alex Nichol]

Number of cylinders
Number of blocks per cylinder
Number of sectors per block

Blocks per cylinder is not a basic. A multi-platter hard disk has
Cylinders, defined by position of heads radially; 'Heads' or tracks,
(one on each platter) and sectors (512 bytes each, along the track).
On a modern HD the number of sectors per track varies according to
length of track - increasing by zones as you go out from the middle.

This CHS direct description puts very awkward limits on things. As
defined you cannot have more than 1024 heads, but can have 64 tracks -
implying 32 dual sided platters, which you never meet in a PC drive. So
for practical purposes addressing is now done in sector number from the
start. But there is still seen to be a logical head and sector number
around when you are partitioning and the partitioning software makes
partitions aligned on these logical cylinder boundaries; every 8MB.
This is sorted out to an actual cylinder, track and sector by the
drive's own electronics

This being called Logical Block addressing (LBA) *may* be what you are
thinking of, but it is *not* a division used in the underlying hardware:
certainly not in the sense of being some multiple of sector. Or
Someone may be using 'block' where everyone else still uses 'track' .

Or you *may* be using 'blocks' where anyone else uses 'clusters' -
the 'allocation units' of typically 8 sectors (4K bytes) for allocating
space to files in a file system - this is *not* related to partitioning
at all. .

 

[Steve N.]

Steve N. wrote:




Blocks per cylinder is not a basic. A multi-platter hard disk has
Cylinders, defined by position of heads radially; 'Heads' or tracks,
(one on each platter) and sectors (512 bytes each, along the track).
On a modern HD the number of sectors per track varies according to
length of track - increasing by zones as you go out from the middle.

This CHS direct description puts very awkward limits on things. As
defined you cannot have more than 1024 heads, but can have 64 tracks -
implying 32 dual sided platters, which you never meet in a PC drive. So
for practical purposes addressing is now done in sector number from the
start. But there is still seen to be a logical head and sector number
around when you are partitioning and the partitioning software makes
partitions aligned on these logical cylinder boundaries; every 8MB.
This is sorted out to an actual cylinder, track and sector by the
drive's own electronics

This being called Logical Block addressing (LBA) *may* be what you are
thinking of, but it is *not* a division used in the underlying hardware:
certainly not in the sense of being some multiple of sector. Or
Someone may be using 'block' where everyone else still uses 'track' .

Or you *may* be using 'blocks' where anyone else uses 'clusters' -
the 'allocation units' of typically 8 sectors (4K bytes) for allocating
space to files in a file system - this is *not* related to partitioning
at all. .

Thanks Alex. As usual, you explain things very well and I appreciate it.

When dealing with partitions using Linux fdisk it always displays
partition with beginning and ending blocks, as well as in size. I don't
know how utils like PM show them as I've never used any. But no, I'm not
confusing block with track nor with FS allocation units. I have more to
understand about this.

Steve

 

[Alex Nichol]

When dealing with partitions using Linux fdisk it always displays
partition with beginning and ending blocks, as well as in size. I don't
know how utils like PM show them as I've never used any. But no, I'm not
confusing block with track nor with FS allocation units. I have more to
understand about this.

That will be referring to a construct of the Linux ext2 file system;
roughly (but only roughly) analogous to clusters in FAT or NTFS.
Internal to the structure of the partition being made, rather than to
hardware operation

 

[Steve Nielsen]

Steve N. wrote:




That will be referring to a construct of the Linux ext2 file system;
roughly (but only roughly) analogous to clusters in FAT or NTFS.
Internal to the structure of the partition being made, rather than to
hardware operation

It shows that way when dealing with any type partition, FAT and NTFS
included, not just Linux partitions.

Steve

 

[me]

wrote in message


and time impugning



I wasn't impugning the question, I was impugning the
questioner. You post wanting to know if your data will be
threatened if you use Partition Magic to recover a tiny,
insignificant sliver of disk space and *I'm* wasting
bandwidth???

Well, the way I look at it is that it's MY disc. I want to know what M$
is using it for, and why. That's why I would ask the question. And, I
don't care how insignificant the "sliver" is---once again, it's MY disc.

 

[Lee Chapelle]

Well, the way I look at it is that it's MY disc. I want to know what M$
is using it for, and why. That's why I would ask the question. And, I
don't care how insignificant the "sliver" is---once again, it's MY disc.

I have it on good authority that M$ uses that space to install tiny digital
cameras which they use to watch you. They can can see you right now. Wave!

 

[Kelly]

Bad, bad, Lee...... )

--
All the Best,
Kelly (MS-MVP)

Troubleshooting Windows XP
http://www.kellys-korner-xp.com