U disk UD file system is what

Now use a U disk to start installation system is very common, and U disk startup files are generally installed in the U disk hidden partition, can prevent the invasion of viruses. Now let's give you a detailed introduction to this hidden partition of U disk.

In fact, U disk's hidden partition is also called UD file system, UD file system is relatively simple. Developers often deal with problems in a way that is simple to do and how to do them. Understanding this, many questions are naturally explained.

1. Do you allow file names with spaces?

First of all, we did not carefully verify whether the space is allowed, I would like to say, even if the space is not allowed, it is natural and reasonable.

There are spaces in the file name, directory name processing, more complex than no space.

For example, if you allow a file name to be delimited,

Copy A B C

Does it mean to copy "a" to "C" or "a" to "B C"?

Since this writing is ambiguous, then this agreement: the user must put the file name in double quotes, written as:

Copy "A B" "C"

This is clear.

But users will complain, my file has no space, but also quotes, annoying. When displaying a list of files, it is annoying to show so many quotes. More people have suggested: I want to put the double quotes themselves as part of a special file name, can you support it?

It seems that adding double quotes also has the annoyance of double quotes.

So, as a developer, what's the simple thing? The Rule UD does not support file names with spaces The simplest!ud is new, and the author can make the rules of the game.

Then encountered with a space to drag into, how to do? No, it's not good. Compromise point, to help you change your name into it.

We may have experience in IE, save the page, if the title has a colon, number and other special characters, then some sites will help you turn into other legitimate characters to keep you, and some sites do not help you turn, the results saved times wrong: The file name has illegal characters.

2.0-byte file

Is too special, also has no practical significance, if handles the trouble, does not support does not calculate.

3. Understanding the UD Directory

How complex is the management directory hierarchy? Don't support it.

But a lot of files, according to multi-level directory management is necessary, how to do?

Get a fake (analog) multi-level directory to deal with, in fact, only a directory hierarchy.

You want to put 0pe.gz in the 0PE directory? OK, I'll put this file in the root directory (in fact there is only one directory hierarchy), but the filename is "0pe/0pe." GZ ", Notice here"/"The number you think is a directory delimited, in fact, only one of the multiple characters that make up the file name. Then, Fbinttool according to the characteristics of the file name, the tree-like structure graphically display UD files, so that you look very "level" sense, really think that UD has a directory level.

In fact, all the files in UD are Higo, all at one level, but some filenames have one or more "/" numbers. This word diggers snaking along, management up how simple ah, really get hierarchy structure, it is much more complex. What if you're a developer? You don't want to save something? Even if you have the momentum to complicate, think about it, the more complex the more error-prone, difficult to maintain, endless ah. Besides, how much is it necessary to get so complicated?

Now you can understand why UD does not support empty directories. That is, you delete a directory of files, the directory will then not exist.

It's easy to experience these. In Fbinsttool, you right-click the Grldr file in the UD Reagan directory and rename it Abc/grldr, and you'll find that Fbinttool shows an extra ABC in UD, and Grldr goes to the ABC directory.

In fact, GRLDR is still in place, only the name changed to take the "/" number, you see GRLDR in the ABC directory, that is fbinttool according to the filename, the original file of the same level, according to the tree-like display of different levels of structure, cheat you, good point is called "simulation", of course, we are happy to this when.

Because there is no ABC directory in UD, only files named "Abc/grldr" are attached to the file, and the directory is simulated. When you delete the Grldr file in the ABC directory with Fbinttool, it corresponds to delete the "Abc/grldr" file, after deletion, there is no file name to start with abc/files, so the catalog ABC also disappeared.