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Using dd to fill a 250 GB partition with 0-bits, I cannot have more than 790 MB written.

dd is run from GParted LiveCD.

I tried all these:

dd if=/dev/zero of=/dev/sdb2
dd if=/dev/zero of=/dev/sdb2 bs=1M
dd if=/dev/zero of=/dev/sdb2 bs=1M count=250000

Note : I don't use shred instead of dd, as I could never erase with it only one partition but only the whole disk.

share|improve this question
please show output of this command: grep sdb /proc/partitions. – mvp Aug 18 '13 at 18:45
what is the actual error message displayed when you "cannot have more than 790 MB written",and what does dmesg say after dd fails? – Matija Nalis Aug 18 '13 at 23:19

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