difference between mount point and physical drive?

[Tim Seufert]

On Friday, October 25, 2002, at 11:49  AM, Michael George wrote:

>
> On Friday, October 25, 2002, at 02:37  PM, Albrecht Dre=DF wrote:
>
>> Am 25.10.02 19:45:05 schrieb(en) Stephen Lewis:
>>> Sometimes it is faster than reading the
>>> filesystem, but because it copies empty
>>> blocks also it might be slower too. If your
>>
>> It's sometimes nice to burn complete partitions compressed on a=20
>> cd/dvd. To avoid that you have random data on the unused space, you=20=

>> can use e.g.
>>
>> dd if=3D/dev/zero of=3Dzerofile bs=3D1M count=3D1
>
> This will fill the disk with data (even if it is all 0's).  I am=20
> guessing that one would want to make sure that nothing else is writing=20=

> to the partition and you don't want to do this to your / partition=20
> (which would be a bad idea anyhow)?

Doesn't matter whether anything else is writing to the partition, and=20
it's perfectly safe to do it to the root FS.  He's using dd to generate=20=

a regular file (named "zerofile"), not to write directly on a=20
partition.  The idea is simply to create a file occupying all the free=20=

space on the target FS, filling it with 0 rather than the leftover=20
random contents from old file deletes.  Later on, gzip will get=20
enormous compression ratios on the long strings of zeroes this=20
generates, dramatically reducing the size of the partition image if=20
there is much free space on the partition.