Re: CD writing faster when CD-ROM also uses ide-scsi

Michael Wardle wrote:
> Hi
> 
> A few weeks back, I purchased a new Lite-On 52x52x24 EIDE/ATAPI CD-RW
> drive, which supports a buffer underrun technology Lite-On calls
> BURNproof (or something similar).
> 
> When I first tried to write a CD image using cdrecord, I was highly
> disappointed that I was only able to successfully write CDs at about 24
> speed (any higher any cdrecord would generate error messages, and the CD
> would be corrupt), regardless of whether BURNproof was enabled or
> disabled.
> 
> My CD-RW drive is the secondary slave on the IDE bus, making it /dev/hdd
> by default.  I also have a DVD-ROM drive as master on the same channel,
> making it /dev/hdc.
> 
> I decided to experiment a little to see whether I could improve the CD
> writing speed.
> 
> After configuring the CD-ROM drive (hdc) to also use IDE-SCSI emulation
> (as the CD-RW must), I was able to successfully write CD images at 48
> speed (the highest speed supported by my CD-Rs) with no BURNproof idle
> periods (the light goes yellow when it's buffering and not writing as it
> did often when the CD-ROM was using IDE, but it now stays constantly
> red).
> 
> I have filed bug 86453[1] to request that Red Hat configure all IDE CD
> drives as ide-scsi.  If anybody has comments on this issue, especially
> if you have also noticed improved performance after configuring all
> IDE/ATAPI CD drives to use ide-scsi, perhaps you could add to this bug.
> 
> To configure your other IDE/ATAPI CD drives as ide-scsi, just add
> <device name>=ide-scsi in the kernel parameters in your bootloader
> configuration file.  My /etc/grub.conf contains something like:
> kernel /vmlinuz-2.4.20-2.48 ro root=LABEL=/ hdc=ide-scsi hdd=ide-scsi
>                                             ^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> You may also need to manually modify the permissions on the new SCSI
> devices to be able to use them fully with programs such as Grip (see bug
> 86452[2]).
> 
> LINKS
> 1. Red Hat Bugzilla Bug 86453
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=86453
> 2. Red Hat Bugzilla Bug 86452
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=86452
> 
> 
> Thanks
> 

I was thinking along the lines of making both devces an scsi device. The 
main reason is that I had to in earlier versions of Red Hat, in order to 
be able to get gnome toaster to know about my cdrom. Without that 
parameter, the cdreader was not recognized.

I'm pretty sure that I tried this trick, using LILO and had to use echo 
"hdc=ide-scsi && hdd=ide-scsi". I'll try adding just the parameter 
string, that you mentioned, for grub. LILO complained about the driver 
already being loaded, if I were to just string the parameters.

Anyway, my cd writer (/dev/hdd) is now considered /dev/scd1. The reader 
only (/dev/hdc) is considered /dev/scd0 and there is a device called 
/dev/sg1 that is linked to /dev/cdwriter now.

I put in a blank disc in my burner. Nautilus opened a burn window and I 
seleceted files to burn. Eventually, I got an error dialog regarding it 
not being able to retrieve information. After closing down the burn 
window, ejecting and re-insertin the newly burned CD. Th files are readable.

This is with kernel-2.4.20-2.54. I hope the cdr burning works a lot 
better with the next release of Red Hat. The trick of referring to all 
cdroms as scsi emulated devices does sound like it might make more of 
the programs behave a bit better together.

The cdrom for the nautilus window still seems to open in the burn 
window. If it ever finalizes, I'll try the newly burned CDR with the 
nautilus burn window later.

Overall, I'm looking forward to the new release.

Jim

-- 
You have a deep appreciation of the arts and music.



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