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So just what *is* the I386 directory anyway?

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I've seen you talk a lot about the I386 directory, particularly for folks that don't have an installation CD for their system. But I'm still confused ... not every machine has this I386 directory, or if they do, it doesn't seem to have what you say it does. What is it, really? Should I have it? What if I don't? Do I want it?

Whoa ... seems my answers around the I386 direectory have been generating lots of additional questions as well. Let's see if we can clarify they "I386 mystery".

Let me start by answering a question you didn't ask, because it's related, incredibly important, and the reason that I386 appears in so many of my answers: In my opinion, you should never purchase a pre-installed operating system without also getting the CD-ROM of the operating system that came pre-installed.

Never.

Clear enough? Now, let me tell you why I feel so strongly, and how it relates to I386.

If your machine has a "C:\I386" directory that contains several thousand files, and that directory takes up over 600 megabytes of disk space then that is the directory I'm talking about. It is most likely a copy of the Windows XP Installation CD-ROM, or the I386 directory that is on that CD-ROM. If you find an I386 directory elsewhere ... say as a subdirectory buried somewhere else on your system, then that is not what I'm discussing here.

Note that I said it's just a copy of the installation CD-ROM. It's not created or installed automatically, it's a copy of the original installation CD-ROM made by whomever set up your machine, usually for two reasons:

  • They didn't give you an actual Windows XP Installation CD-ROM, so give you the copy on the hard disk only instead
  • It's a shortcut to make it easier, later, if Windows asks for the installation CD-ROM

Those two are related.

As an example, when you add hardware to Windows - say you add a new printer - Windows needs to get the appropriate files to support that new device. Since it wasn't connected to your computer when you set up Windows, those files were not installed then; they need to be added now. Where do they come from? The Windows Installation CD-ROM.

But what if you didn't get a CD-ROM when you purchased your computer? By having a copy of an installation CD-ROM in the C:\I386 directory, when Windows asks for the original CD, you can tell it to look there instead. So even though the manufacturer didn't give you a physical CD-ROM, everything you need is already on your hard disk, right there in C:\I386. When Windows needs something from the original install CD, it can locate it there instead.

Can you see the flaw in this setup?

What happens if your hard disk crashes? What happens if you need to reformat your hard disk? Everything is erased - including C:\I386. If you don't have an actual, physical, CD-ROM to reinstall from, you're screwed - to put it mildly.

The second reason for C:\I386 existing is simple convenience. Even if you have the CD-ROM, as you should, it's often more convenient to keep a copy on your hard drive. That way, instead of reaching for the CD-ROM each time Windows needs something, you can just tell Windows to pick it up from C:\I386, already on your hard disk. In fact, it's such a convenience, and disk space is so plentiful these days that copying the Windows XP CD-ROM to my hard disk is often one of the first steps I take when I'm about to set up a new machine.

So what does all this mean? Well, remember that C:\I386 is just a copy of a Windows Installation CD-ROM. Hence:

  • You may not have C:\I386 on your machine. It's certainly not required. Hopefully you'll have a Windows CD-ROM, should you need it.
  • You may have C:\I386, but no Windows CD-ROM. I encourage you to a) backup the C:\I386 directory you do have, and b) if you can, pester your computer manufacturer for a physical CD-ROM.
  • You may have both.

C:\I386 is not required for Windows to function. You can certainly copy it elsewhere, perhaps to a different drive, or back it up to CD-ROM or DVD. (Even though it's a copy of a CD-ROM, some manufacturer's appear to add to it, so that the actual C:\I386 will no longer actually fit on a single CD-ROM).

But it is convenient.

Related:

Article C2457 - November 13, 2005

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Recent Comments
42 Comments

Re.

"How can I create a Bootable CD from my i386 Folder ?
You can't, really....."

Yes you can. Do a Google search before you shoot from the hip. Try "Create a bootable XP CD" I get 32,000 results for that one, with clear instructions for using i386 for just that purpose within the top 10. Both the questioner and the advisor should investigate this new Internet phenomenon called the "search engine". It works with plain english questions. And please, Leo, buy Google a latte.

Posted by: steve at December 16, 2008 9:29 PM

Re:
"You might look into BartPE, which can build a bootable Windows CD from your existing installation."

And last I looked BartPE required an original Windows Installation Disk, since Bart was not trying to recreate it! BartPE's function is to produce a LiveCD. You might try reading the info on that site, as well. If you do, and it affects your advice here, buy Bart a latte, too.

Posted by: steve at December 16, 2008 9:40 PM

Sure sure, very informative perhaps but not on the matter of finding the CD-ROM itself if you never got it! Microsoft doesn't always give out the CD-ROM anymore because of software piracy issues, so we're basically screwed if we don't have it. NOW: is there any place to download the contents of the CD-ROM if you don't have it or can't get it?

Search this site and you'll find this article: Where can I download Windows XP?
- Leo
23-Dec-2008

Posted by: D. Diuran at December 22, 2008 5:28 PM

I just recently bought The Embodiment of Scarlet Devil, and was told by several friends that I would need Applocale to run/install it. When I open Applocale and select the language needed to run the program, it says that the language support for that language has not been intsalled. So when I go to the regional options, and try to install the files for East Asian Language support, it tells me I need the CD.

I have no CD.

I have no i386 folder.

How do I get this language support i need without eating up 800MB of space? And is there a way to put the language support onto a flash drive, so all I have to do is move a copy of the needed files to the required location(s) when I access a computer?

(I can only access using public comps, and they use programs that completely wipe/reset the computer every time it's shut down. It's like DeepFreeze or something, brings the computer back to a restore point automatically.)

Posted by: Kitaen Fauxlorin at February 2, 2009 1:41 PM

Sorry Leo - I must be thicker than the average

I have a Lenovo PC which has pre-loaded XP and I don't have a CD for any of the programmes that it came preloaded with. Apparently they are buried away somewhere in the innards of the PC where they can be invoked if need be.
However as so so succintly put it, if the drive goes down they might as well be made of smoke.

So I was interested in your I386 articles.
I have a directory C:\I386 with some 6226 files in it (including the winnt** files you specified)

This is the thick bit
Can I simply copy this directory to a new CD and write on it the product key (thanks for the link to that programme also). Having done this when my hard drive dies I will have the means to reload a new hard drive {{I have no intention of cheating Mr.G and have a product which I did actually pay for even if it was bundled into a PC}}

regards
Bernard

Yes, BUT ... the one thing you won't have is something to boot from. (Copying the I386 folder as you describe does NOT create a CD you can boot from.) Unfortuantely those steps are more complex than I can get into here, but one could start at bootdisk.com.
- Leo
19-Feb-2009
Posted by: Bernard at February 18, 2009 11:29 AM

Thank you!!!! I'll be bookmarking your site. I'm trying to go open source, but do not speak tech. Trying to figure out which file is supposed to work with my "achitecture or operating system" is insane. .tars, .wars... I have no idea. I now have a backup disk for my new Vista laptop! Whoo hoo! On to looking up AMD64 now...

Posted by: Alice at April 1, 2009 11:31 PM

Just out of curiosity, is the I386 directory only connect to windows installation or is the directory the same for other thing like say lter windows programs that are not supported by the original installation cd but will still run on your current version.

Posted by: Jay at August 24, 2009 5:14 AM

One other reason not to rely on an i386 directory - more than once I have seen malware modify or replace files in that directory with its own permutations. Think you're going to fix your infected pc by reinstalling from files stashed on your (infected) HD? Think again.

At least you can rest assured that the files on the original install CD ARE still the original files.

Posted by: Peg at October 5, 2009 4:51 PM

Can you verify that it would be OK for me to cut and paste the I386 folder in full to my external hard drive. It would be very useful if I can, as my Laptop is quite old and needs all the memory it can get!!

Sure, that's this article: Can I move or delete my I386 directory to free up some space? - but remember that doesn't free up memory (RAM), it frees up disk space.
Leo
24-Oct-2009

Posted by: Richard Cassley at October 22, 2009 2:04 AM

I have tried to recover an emachine pc. I have recovered all but 1, c:/1386/netclass.IN it says file is corrupted is there anything I can do. OS

Posted by: Aunohea at November 4, 2009 1:47 PM

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