10 replies to this topic

[eddie]

Hey!

I was just reading a post on the 2BrightSparks forum here, and one of their developers writes:

"Those of you who've tried UndeleteOnClick will know that it can scan the disk and produce a list of every file and folder on a disk in just a few seconds. On my development PC it can return all 10,000+ files and 5,000+ folders in less than two seconds. That's very quick. It can do this because it reads the file and folder information directly from the disk instead of using the usual Win32 API's (FindFirst, FindNext)."

To me, that's rather vague. I'd love to know how he's done this. I'm tempted to ask him outright, but I'm sure that a developer telling people about their secret sauce on a work website is a no-no.

Anyone have any idea what he means about "reads the file and folder information directly from disk"? Does he manually parse the file table structure? If so, are there API's for that, or would he be leveraging some in-house code for that?

Curiouser and curiouser....

[Ed Mack]

Being from a nix viewpoint, I'm surprised you have raw access to the disk from a user program!

[Reedbeta]

There are data recovery programs like GetDataBack and so forth that try to read the raw structure of a bad disk, so presumably some kind of API for that exists in Windows.

[eddie]

That's what I would assume.. Hrmm.... It's one of those things that I don't need urgently, but it would be nicer than FindFileFirst() and crap. :)

One day I'll find it.. One day...

[roel]

You can get raw access to the disk using the usual CreateFile API, giving "\\.\PHYSICALDRIVE0" or "\\.\C:" as filename. And then you should manually parse the FAT/NTFS/whatever structures. And I believe that it will be way much faster indeed.

[Alex]

I hope you don't intend to write to an NTFS partition directly though..many have failed at that.

[roel]

Yeah, that seems quite dangerous to me too.

[eddie]

Hah, no.

I'll be looking for information off of it. I can stand normal file writing operations. ;)

[.oisyn]

What about just opening a directory? (which can also be done by CreateFile)

[eddie]

.oisyn said:

What about just opening a directory? (which can also be done by CreateFile)

... what about it? (Sorry, I don't know what you're asking).

[.oisyn]

Maybe that's also faster than findfile, although a findfile probably does the same thing