Subject: Re: Question about raw vs. block devices
To: None <current-users@NetBSD.ORG>
From: Christoph Badura <>
List: current-users
Date: 02/25/1997 01:19:00
khym@bga.COM (Dave Huang) writes:
>What exactly is the difference between, say /dev/rcd0a and /dev/cd0a?

The most important difference is that the block device (cd0a) is
accessed through the buffer cache while the raw device (rcd0a) isn't.
As you found out, the latter requires you to use a multiple of the
device's block size.

>However, "dd if=/dev/rcd0a bs=2k"
>and "dd if=/dev/cd0a" don't return the same data. Even "dd if=/dev/cd0a
>bs=2k" gives different data than reading from the raw device, which seems
>rather strange to me...

That's not supposed to happen.  If you can't blame it on the NCR
driver :-), I'd say, send in a PR.

Christoph Badura

You don't need to quote my .signature.  Everyone has seen it by now.
Besides, it doesn't add anything to the current thread.