Why does Win 7 say 21.7 GB == 17.8 GB

[Alan_B]

The properties of C:\ show a capacity of 49.9 GB, with only 17.8 GB used

When I select all the contents of C:\ the total size is 21.5 GB

and the Size on Disk of all the sectors in use is 21.7 GB.

 

Previously with 32 bit XP the Used Space was always MORE than the Size on Disk because :-

My daughter's profile was excluded from what I could include as being the contents of C:\ ;

and possibly Alternate Data Streams and Metadata do not get included with 73,254 files, but still use space.

 

How can 21.7 GB use only 17.8 GB.

 

Is this another of the features of a 64 bit Windows,

or do I have files totalling 3.9 GB which are double counted because of Reparse Points ?

[Aethec]

It's probably because Windows Explorer still doesn't handle junction points and all that stuff correctly,

[Winapp2.ini]

Windows confuses it self with the hardlinks and junction points, reporting sizes of much higher values than are actually in use. The WinSxS folder is tribute to this.

[Alan_B]

Thanks for confirming my Reparse Point suspicion.

I was been afraid I had stumbled across some other peculiarity in 64 bit Windows 7.

 

I recognise this effect from my experience with 32 bit XP when I duplicated 6 folders on a non-system partition,

and then replaced the original folders with reparse points aimed at their duplicates.

 

Almost all applications still thought the folders were where they had been installed,

and the HP Printer continued to work as usual.

Only tools such as the Defragger and Acronis Partition Image backup software knew different,

and Windows Explorer ignored them if they were one sub-folder level down.

e.g. select all items at C:\D\* and right click for properties,

then the sum total would include C:\D\R1 but exclude C\D\E\R2

where R1 and R2 were reparse points.

 

I know that W7 has more than 40 reparse points,

but does it really have 20% of all files targetted by reparse points based at C:\

or does W7 Windows Explorer count what XP Windows Explorer excludes ?

[Aethec]

In Windows 7 (and Vista), the WinSxS folder (which was created as a solution against DLL Hell) contains a lot of reparse points. Thousands of them.

...thank badly written software for that.

[Alan_B]

I designed high reliability embedded software for continuous security protection of shopping centres and military installations.

They never had a BSOD or a software crash - it was always defective silicon.

 

For various manufacturing purposes I had to use Windows to create documentation for production.

 

I had a failure of one of the in House Office applications I was required to use.

I called in the developer and he re-installed his software.

A different application and a different developer, but the same answer - re-install.

 

I found the problem was that each developer had a slightly different version of Visual Basic,

and they created incompatible DLL's that used the same names,

and each time one application was installed it replaced DLL's needed by the other application.

 

I learnt that there were ways of coding to avoid the problem,

but our in-house developers had no such competence - they could not even agree on a common version of V.B.

 

20 years ago I suffered DLL hell.

I still cannot forgive Microsoft for enabling children to throw a few lines of code together in an attempt to do a real man's job ! !

 

I have just looked at Winsxs and it uses 5.66 GB in 39,693 Files, 10,045 Folders.

The entire contents of Windows excluding Winsxs is 5.81 GB in 23,459 Files 3,153 Folders.

DLL Hell needed a solution, but Linux keeps on looking better and better ! !

[Aethec]

Windows Explorer does not report the actual size of WinSxS. It's "only" a few hundred megabytes.

 

(source, in French: http://blogs.msdn.com/b/e7fr/archive/2009/01/19/9341096.aspx it seems there is no English version of this article...weird)

[Alan_B]

I still remember how to "Open the Door" and "Stand on the Table" in French,

but I forget how to "Open the Window" or anything else from French lessons last century,

so I cannot understand the text in that article.

 

But that article shows the snapshot of winsxs properties displaying a size of 10.7 GB.

 

Are you saying that out of 10.7 GB there are only a few hundred megabytes of original files resident with the folder,

and the other 10 GB are all reparse duplicates(triplicates) ?

 

Supplementary question :-

Why can I read all the labels on the Tabs in that snapshot ?

Is that a snapshot of an English language P.C.,

or is it only File Paths and DOS error messages that change with the language ?

[Aethec]

Yes, it's only a few hundred MBs. And I have no idea why the screenshot is in English. I didn't find any English version of that blog post

 

En fait, pratiquement chaque fichier dans le dossier WinSxS est un lien ? physique ? vers les fichiers r?els dispers?s dans le syst?me - ce qui signifie que les fichiers ne sont pas r?ellement dans le dossier. Par exemple, vous trouverez dans le dossier WinSxS un fichier appel? advapi32.dll occupant plus de 700KB, mais le r?el fichier advapi32.dll est dans le dossier Windows\System32, et sera compt? deux fois (ou plus) si vous regardez dans les dossiers individuels avec Windows Explorer.

 

In fact, nearly all files in the WinSxS folder are "physical" links pointing to the real files in the system - which means that the files are not really in the folder. For example, you'll find in the WinSxS folder a file named advapi32.dll which occupies 700 KB, but the real advapi32.dll file is in the Windows\System32 folder and will be counted twice (or more) if you look into the individual folders in Windows Explorer.

 

 

L'espace de stockage r?ellement utilis? varie, mais sur un syst?me ordinaire il est ? peu pr?s de 400MB. Bien que non n?gligeable, nous pensons que les b?n?fices apport?s aux mises ? jour en justifient le cout.

 

The storage space actually used can vary, but on a normal system it is circa 400 MB. Even though that's not negligible, we think the advantages given to the updates justify the cost.

[Alan_B]

Thanks.

 

The more I learn about Reparse Points the more I fear them.

 

My sanity cannot take any more ! !