Using DD every single day (on UNIces and Windows, both) is where the cheap idea for a DOS environment came from. Also, you can use bs= XXX to increase the filling speed.
If not, you can install the Zero and Random Device Driver by Olof Lagerkvist, then do dd if=\\.\zero of=0 and fill up your empty space.Īlways a good idea to defragment and make all files as contiguous as possible, before-hand.
I believe that recent versions of DD for Windows will accept the above command exactly. This is the FreeDos and Dos area.ĭd if=/dev/zero of=filler. Thanks TheK for pointing out sDelete.I would have pointed out DD for Windows by John Newbigin and Chrysocome, but you said DOS, which is != Windows. OT: Off-topic And no, normally people don't abbreviate "on-topic". > What does OT mean? How would you abbreviate its opposite?
The advantage of sparse files is that storage is only allocated when actually needed: disk space is saved, and large files can be created even if there is insufficient free space on the file system.Īnyway, I think this brain-dead brute-force method works for me. I guess ordinary Windows user would have a hard time trying to under this because they don't have the concept of a sparse file. * it (temporarily) uses all free space on the disk, so other * it makes the disk image (temporarily) grow to its maximal extent Has many disadvantages, which zerofree alleviates: The entire free space on the drive, and then delete this file.
The usual way to achieve the same result (zeroing the unusedīlocks) is to run "dd" do create a file full of zeroes that takes up The following is taken from the description from zerofree package, which zero free blocks from ext2/3 file-systems: A happy medium might be repeatedly doing type 512.bin>filler.Īctually, all above can be done with a single command under Linux (no wonder I wasn't able to find such tools under Linux): The method above would be much faster, but could run out of room just past the half-way point. You can create the initial dummy file with echo.>dummy.txt.ĮDIT: Actually, it might be better to "slow-fill" the file by continually appending to it. You can make a DOS batch file that simply loops until an error condition and copies a file together with itself until the copy fails because you've run out of room. Conversely, zero-byte files must use some disk space to be indexed by a filesystem, though none for content.In case anyone else is interested, basically, as the empty free space is concerned, it's method is exactly as outlined by Sha0, just filling the free space with zeros, as opposed to anything else: Some very simple formats do not use metadata, such as ASCII text files these may validly be zero bytes (a common convention terminates text files with a one- or two-byte newline, however). When the zero-byte file is made, file system does not record the file's content on storage, but only updates its index table.Įven a file describing an empty word processor document, an image file with zero-by-zero dimensions, or an audio file of length zero seconds usually still contains metadata identifying the file format and describing some basic attributes of the file it results in the file with some positive size. Because writes are cached in memory and only flushed to disk at a later time ( page cache), a program that does not flush its writes to disk or terminate normally may result in a zero-byte file.
Zero-byte files may arise in cases where a program creates a file but aborts or is interrupted prematurely while writing to it. On Unix-like systems, the shell command $ touch filename results in a zero-byte file filename.
There are many ways that could manually create a zero-byte file, for example, saving empty content in a text editor, using utilities provided by operating systems, or programming to create it.