Here you will find various ways of manually creating a dummy file to be used as a coLinux swap partition.

Note: The content of the swap file doesn't matter, you'll only need a file with the appropriate size.

For details how to add a swap partition to coLinux, see the AddSwapPartition page.

Note: After replacing the swap file, if you have the message "Unable to find swap space signature", you may need to do the following:
mkswap /dev/cobd1

Using (copy) an already existing file[]

If you already have such a file with the desired size in your Windows system, you can simply copy that one into the coLinux directory, and name it as you want, eg. swap-file.

Using Windows-builtin tool fsutil (XP and later Only)[]

Note: You must have administrator privileges to call fsutil.

Go to Start->Programs->Accessories->Command Prompt

fsutil file createnew c:\colinux\swap_file 1000000000

Instead of 1000000000, you could use the following sizes:

  • 64M: 67108864
  • 128M: 134217728
  • 256M: 268435456
  • 512M: 536870912
  • 1024M: 1073741824

It creates sparse files, so the creation is very quick.

boots: as a W2K user, I had never heard of this tool before. Looks interesting. Here is XP Doc page for Fsutil, straight from the horse's mouth.

Additional info:

Using Contig[]

One of the features of Sysinternals Contig is the creation of files. It then attempts to defragment the file:

contig -v -n swap-file 536870912

will create a 512Mb file.

Using Cygwin[]

It is possible with Cygwin by using a Unix command like dd :

dd if=/dev/zero of=swap-file bs=1024k count=512

will create a 512*1024*1024 bytes aka 512Mb file.

Using notepad[]

Very stupid way how to create any file, preferable 2^N size:

  • Open notepad, create a new text file containing only the letter "a" and save it as "swap.txt"
  • Go into the directory containing "swap.txt" and check that it is only one byte using dir.
  • Double the size of the file as required by using "type swap.txt >> swap.txt".
  • Each time you call the previous line, it will double the size of the file. Executing it 10 times will give a one kilobyte file. 20 times will give a one megabyte file.

Times executed=Resulting filesize(mb)

20=1mb 21=2mb 22=4mb 23=8mb 24=16mb 25=32mb 26=64mb 27=128mb 28=256mb 29=512mb 30=1024(1gb)

Or you could type on COMMAND(DOS) window:

>copy con myfile
>type myfile>>myfile
>...... repeat,repeat,repeat,....

Using Bochs Windows port[]

It's easy to create a file of a given size on Windows using the Bochs Windows port. You need their tool called 'bximage' to do the job.

a.) Go to the Bochs Download Page:

and download

b.) Extract from this archive the file 'bximage.exe' which is a stand-alone binary and put it in a suitable directory.

c.) Open up a Windows Command Prompt, cd to the coLinux installation directory, and run bximage.

d.) Create a hd image, flat image.

e.) Specify the size of the swap file you want in MB (I created a big 1024MB swap file).

f.) Choose the file name you want (e.g., swap-file).

g.) Ignore the bochsrc info statement and hit enter. You're done creating an empty file to use as a swap file!

There is a native WIN32 dd port at (search for GNU fileutils).

There's another very nice Win32 dd port at

MassTranslated on Sun Apr 23 17:36:18 UTC 2006