[Solved] Having problems burning a DVD

[James Phillips]

--- On Fri, 12/4/09, Al Plant <noc at hdk5.net> wrote:

> From: Al Plant <noc at hdk5.net>
> Subject: Re: [Solved] Having problems burning a DVD
> To: "James Phillips" <anti_spam256 at yahoo.ca>
> Cc: freebsd-questions at freebsd.org
> Received: Friday, December 4, 2009, 12:26 PM
> James Phillips wrote:
<SNIP!>
> > I noticed that the hash does not match the ISO file.
> Is that normal for DVDs? For CD images I often get the md5
> hash to match.
<SNIP!>
> Aloha JP,
> 
> This is what I use on FreeBSD from the command line to burn
> DVD's.
> I have used it on FreeBSD 8* for a while. (Simple and it
> works.)-
> 
Yes, I got that far, hence the [Solved] tag.

I was mainly concerned that I made a mess of my /boot/loader.conf

I am also a little concerned that the DVD only reads a ~1.5MB/s (a little faster than 1x), but it appears to work. Burning happened at ~7x according to growisofs.

> 
> Then> Run # growisofs -dvd-compat -Z
> dev/cd0=/usr/home/alp/FreeBSD_7/7.2-RELEASE-p1-i386-disc1.iso
> (all on one line)
> 
> Then> Use  cd0 as a DVD burner and make the DVD-R
> 
> I tested the DVD on a spare box and it installed just
> fine.
> 

I found out why the checksum didn't match: the "-dvd-compat" option adds 6 2048 byte sectors of zeros to the end of the disk.

So, I was able to verify the md5 sum by reading only the number of sectors present in the iso file.

$ dd if=/dev/dvd bs=2048 count=996586 | md5

I noticed the size discrepancy while doing a binary search using the iseek (dd)(and count) argument(s) to narrow down the location of the corruption.

Regards,

James Phillips



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