Re: [9fans] cdfs(4) multi-track DVDs

[erik quanstrom <quanstro@quanstro.net>]

> cdfs(4) contains a paragraph in BUGS that reads:
>           Closing a just-written DVD-R track can take minutes while
>           the drive burns the unused part of the track reservation
>           (for the whole disc).  Thus only a single DVD-R track can be
>           written on a DVD-R disc; use other media if you need more
>           than one track per disc.
> i know the array of media is confusing, but should i read this to imply that
> DVD+R media are expected to support multi-track writes?

yes.

>  i just did something more or less like:
> 	for (i in 0 1 2 3 4 5 6 7)
> 		{venti/rdarena /dev/fs/arenas arenas0.$i > /mnt/cd/wd/$i}
> the results were not what i had expected: i got d000, which looked
> correct, and d001 which, upon cursory examination, looked like the
> concatenation of arenas 1-7. am i just SOL with multi-track DVDs?

with a dvd+r, this appears to work for me
	; cp /sys/src/9/pc/sdiahci.c /mnt/cd/wd
	; cp /sys/src/9/pc/sdorion.c /mnt/cd/wd
	; lc /mnt/cd
	ctl	d000	d001	wd

except a disk in this condition confuses cdfs

	; echo eject >/mnt/cd/ctl
	; echo ingest>/mnt/cd/ctl
	; lc /mnt/cd/
	ctl	wa	wd

that's definately wrong.  but after restarting cdfs
i get
	; lc /mnt/cd
	ctl	d000	d001	wd

and adding tracks works, too.
	; cp /sys/src/9/pc/sdata.c /mnt/cd/wd
	; lc /mnt/cd
	ctl	d000	d001	d002	wd

scuzz shows what's happening.  note that there's no way to
close the session so all the tracks appear in the first session.

	rdiscinfo
		data length: 0x20
		info[2] 0x05
			Incomplete disc (Appendable)
			Incomplete Session
		Number of First Track on Disc 1
		Number of Sessions 1
		First Track Number in Last Session 1
		Last Track Number in Last Session 4
		info[7] 0x00
		info[8] 0x00
			CD-DA or CD-ROM Disc
		Last Session lead-in Start Time M/S/F: 0xFF/0xFC/0x00
		Last Possible Start Time for Start of lead-out M/S/F: 0x23/0x05/0x40


- erik