[cygwin] DD bug fails to wipe last 48 sectors of a disk

[Hashim Aziz]

I have no idea what bottom posting is, mailing lists are new to me and I find them a very archaic and noisy way to communicate development changes. I really wish the Cygwin dev team would enter the 21st century and move to a modern development process involving a repository like Github, I'm convinced it would increase developer engagement with the project massively while cutting down on so much of the noise.

I ran:

dd if=/dev/zero of=/dev/SDA bs=4m oflag=direct status=progress

...and can confirm the bug still presents - the last 48 sectors fail to be wiped.

________________________________
From: Andrey Repin <anrdaemon@yandex.ru>
Sent: 24 June 2020 11:21 AM
To: Hashim Aziz <hashaziz@hotmail.com>; cygwin@cygwin.com <cygwin@cygwin.com>
Subject: Re: [cygwin] DD bug fails to wipe last 48 sectors of a disk

Greetings, Hashim Aziz!

Bottom posting in this channel, please.

> I've just tested with the command:

> dd if=/dev/zero of=/dev/sda iflag=fullblock bs=4M status=progress

oflag=direct

Although I'm unsure how Cygwin/Windows handles it. But without this flag, the
write is cached, and the problem may be outside dd, or even Cygwin.

> ...and can confirm that the last 48 sectors remain unwiped in this case also.

> Here is the output:

> 1000182120448 bytes (1.0 TB, 931 GiB) copied, 8284 s, 121 MB/s
> dd: error writing '/dev/sda': No space left on device
> 238468+0 records in
> 238467+0 records out
> 1000204861440 bytes (1.0 TB, 932 GiB) copied, 8284.89 s, 121 MB/s


--
With best regards,
Andrey Repin
Wednesday, June 24, 2020 13:19:42

Sorry for my terrible english...