On 12/18/2022 5:08 PM, Samuel Sieb wrote:
On 12/18/22 14:03, Bill Cunningham wrote:
>
> On 12/18/2022 4:47 PM, Samuel Sieb wrote:
>> On 12/18/22 13:40, Bill Cunningham wrote:
>>> IDK if you can do this or not. Say if you have a file that is 2.048
>>> Gig and it is attached to a loopback device, say /dev/loop0,
>>>
>>> losetup /dev/loop0 FILE_NAME,
>>>
>>> And you tried cdrwtool -d /dev/loop0 -q;
>>>
>>> Now I have tried this and get errors. IDK if there's a way around
>>> this, a safety issue that is built in, or maybe I am not using the
>>> right program to format a "dvd".
>>>
>>> Can you dvdformat a loopback device?
>>
>> No, that doesn't make any sense. The formatting is a physical
>> thing. For a disk image, you just make an .iso file. You can later
>> write that to a physical disk.
>>
>> What are you trying to do?
>>
> I thought I would make the format, observe the detail then copy. For
> example, I can format a loopback and observe the data with a hexdump
> like xxd. This seems to work and thre is no physical device,
>
> I use dd to create a 2.048 Gb zero'd file, for example.
>
> losetup /dev/loop0 FILE to mount the loopback,
>
> mkfs.vfat -F 32 /dev/loop0
>
> and detach and xxd -g1 FILE.
>
> There is a formatted FAT32 filesystem. Why can't this be done with a
> DVD format UDF file?
Because the format doesn't work like that. It's designed for
sequential writing, you don't random access write to optical media.
(At least for CD and DVD.) The format command just writes the
initialization information to the optical media, it's data for the
drive, not part of the filesystem.
You use one of the iso tools to create UDF files, you don't need a
loopback for it.
OK so how exactly do I create an "empty" ISO file? I will try to explain
by example.
As above say I have an "empty" vfat format.
mount /dev/loop /mnt which is attached to a FILE.
copy files manually into the /mnt directory. Be they VOBs IFOs or such.
wold I have to turn to mkfs.udf for this? IDK if that is a ISO.
B