writing large files quickly

[rbt]

Grant Edwards wrote:
> On 2006-01-27, Tim Chase <python.list at tim.thechases.com> wrote:
> 
>>>>    fd.write('0')
>>
>>[cut]
>>
>>>f = file('large_file.bin','wb')
>>>f.seek(409600000-1)
>>>f.write('\x00')
>>
>>While a mindblowingly simple/elegant/fast solution (kudos!), the 
>>OP's file ends up with full of the character zero (ASCII 0x30), 
>>while your solution ends up full of the NUL character (ASCII 0x00):
> 
> 
> Oops.  I missed the fact that he was writing 0x30 and not 0x00.
> 
> Yes, the "hole" in the file will read as 0x00 bytes.  If the OP
> actually requires that the file contain something other than
> 0x00 bytes, then my solution won't work.
> 

Won't work!? It's absolutely fabulous! I just need something big, quick 
and zeros work great.

How the heck does that make a 400 MB file that fast? It literally takes 
a second or two while every other solution takes at least 2 - 5 minutes. 
Awesome... thanks for the tip!!!

Thanks to all for the advice... one can really learn things here :)