Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am working on Windows 7 Ultimate.

I have an ISO file and need write access to it. On virtual daemon I only can simulate CD-ROM drives without write access. Is there any mounting software that can simulate a flash drive, or can at least give write access to the ISO?

share|improve this question
The usual tool was PowerISO, but I now see things like UltraISO and Power10ISO in searches. These pages sound fishy (UltraISO also refers to PowerISO!). This is a heads-up; beware what you download. – nik Jul 20 '11 at 15:39
UltraISO is legit. It will edit an ISO and it will mount one as a virtual drive. I've never heard of Power10ISO. – Loren Pechtel Jul 20 '11 at 17:47
Depending on the software, you can just copy the contents of the ISO to a folder and it runz like a machine. – surfasb Jul 20 '11 at 18:02
I've tried with Alcohol 120% but when using "CD-RW" option it does not work. Perhaps I will use PowerISO Demo as next step. – Nasenbaer Jul 20 '11 at 18:42
Maybe you should tell us why you want to simulate a USB flash drive instead. I can't think of any good reasons why you would ever want/need to do that, and maybe the best solution to your problem is best answered by a different question. – Breakthrough Aug 2 '11 at 0:39
up vote 3 down vote accepted

Have you tried using a Virtual Hard Drive? It will allow you do just this, with no additional software or hardware.

In Windows 7, using Disk Management, you can create a Virtual Hard Disk (VHD), and attach it as a drive on your computer. You can then assign it a drive letter, and partition it, like a normal drive.

The VHD is a file, that resides on your hard drive. You have two options:

  • Dynamically sized - The file will start out very small, and will expand to fit its contents. You specify an upper limit to how large the file can get.
  • Fixed size - You specify the size of the file. It will always be that size, no matter how much data is actually stored in it.

A walkthrough on how to do this is here:

share|improve this answer

I don't think this is possible with an ISO image - you can't "write" to a disc image. That's not what the format is for. There is no such thing as a CD drive which can directly write files to a CD.

You can, however, use a tool like MagicISO or PowerISO to remove or add files to an existing ISO disc image. That being said, when you actually save the ISO image, it ends up re-writing the entire disc image due to the way the format is.

Finally, if the underlying filesystem in the ISO file is UDF-based, it may be possible to implement writing directly to the virtual drive by letting it act as a virtual CD-RW. That being said, I believe the performance hit would be a lot worse then just using an ISO editing tool.

If you want to simulate an actual flash drive, what you're looking for is a virtual filesystem. One of the easiest ways would be to use TrueCrypt to create a virtual (encrypted) filesystem in a single file. You can then mount that file and use it like any other hard drive/flash drive. Unmount it, and your data is stored in a single file (which you can re-mount whenever you'd like, on any computer system).

There are alternative programs which can do the same thing (and without the encryption), but TrueCrypt is free, open source, cross platform, and pretty easy to use.

That being said, since you commented on what you really are trying to accomplish, you should use a virtual floppy disc emulator. This will allow both read/write access to the virtual drive, and should work with the appropriate drive letter.

share|improve this answer
Second this. The format can't tolerate most forms of modification as it's basically the relevant information written out in order. Change the size of anything and everything after that point has to be moved. – Loren Pechtel Jul 20 '11 at 17:51
TrueCrypt may be free, open source, cross platform, and easy to use, but VHD support is built into his OS, and also quite easy. – Mike Christiansen Aug 2 '11 at 0:48
The VHD format is also a proprietary Microsoft format and not natively supported on other operating systems (or even anything pre-Windows 7). – Breakthrough Aug 2 '11 at 0:50
Well, that depends on his OS choices. It is supported in a couple different virtual environments. If nothing else, it meets his needs for now... – Mike Christiansen Aug 2 '11 at 0:52
I don’t think that Nasenbaer is looking for disc-image editing software. It sounds like they want something that can be updated while live. Also, there is no reason that some software cannot mount an image and allow writing to it. Look at Drive Snapshot; it allows you to clone your drive to an image, and then later mount that drive. You can cut, copy, paste, and delete files to and from the virtual drive. (In this case, the changes are discarded the way that a VM can be set to do, but there’s no reason that software can’t be made to commit them as well.) – Synetech Aug 2 '11 at 1:10

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .