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Old January 19th 08, 03:05 PM posted to comp.arch.storage
Cydrome Leader
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Posts: 113
Default Utility to write huge files instantly???

mike wrote:
Cydrome Leader wrote:
mike wrote:
Windows 2000, FAT32 or NTFS.
For testing,
I want a utility to create BIG files ~1GB on storage media
quickly.

Copying a big file is not an option, too slow.

I don't care what's in the file as long
as the OS is happy that it's a "valid" file.
Needs to work thru normal OS drive letters and drivers.

Should be able to just write the FAT without doing anything to the
actual allocation units being allocated???

Anything like this exist?
Thanks, mike


There are ports of the "dd" unix program for windows. It can be used to
write giant files with minimal effort.


Thanks, but minimal effort is not nearly as important as minimal time.
The version of dd I tried does work,

dd if=infile of=outfile seek=2000000
if is 200bytes.


set a larger block size, bs=65536 etc. The default 512 byte blocks are
slow.


but it's only marginally faster
than copying a file. I need something that's a thousand times or so
faster than a file copy for a 1GB file.

Maybe there's a version that doesn't fill the file with zeros, but just
allocates the space?? Think about copying 16 gigabytes to a
USB1.1 drive...while we're still young.


Unless you want sparse files, what you want isn't going to happen.

16GB over USB 1.1 is just nonsense to start with.

So, if you want to actually write lots of data, you're going ot have to
wait. If you want giant empty files where the insides don't matter, you're
not copying large amounts of data in the first place. The same applies to
sparse files.