I have made some more tests on the performance of cd0,
using different CD's and operating systems.

1) Windows NT (which I have on the other partition)
   copied a 650 MB CD to the _hard disk_ in 7'18"
   (about 1496 KB/sec).

2) Debian Linux 2.1 (booted from CD): 'dd' copied
   the CD to /dev/null in 4'10" (~2422 KB/sec).

3) NetBSD 1.4.1: 'dd' to /dev/null achieved a transfer
   rate of ~300 KB/sec.

I think there is a performace problem and the hardware
is not to blame.  I am probably completely wrong but I
have the impression that there is a performance
penalty when an ATAPI CD-ROM is a slave to a hard disk.
cd1, which is secondary master, works much better.

Regards,
Federico Lupi


Original message:

> I have changed my PC to a PIII 450, Intel SR440BX, 128MB.
> 	wd0  Quantum Fireball (7200 rpm)
> 	cd0  Asus 40x (ATAPI)
> 	cd1  HP CD-Writer Plus 8100
> 
> PROBLEM: the performance of the Asus 40x is very poor.
> 
> When I give the following command:
> 	dd if=/dev/cd0d of=/dev/null bs=100b
> the output of 'systat iostat' for cd0 (Asus) is
> 	cd0  KBps   102.8
> 	     tps
> The same command on cd1 (HP) results in
> 	cd1  KBps   518.8
> 	     tps    259.4
> This is very strange: the Asus should be much faster than the HP.
> 'systat vmstat' gives similar figures
> for Asus:
> 	        cd0      64 irq 14      99.8% idle
> 	xfers    61
> 	Kbyte   122
> 	sec     1.0
> for HP:
> 	        cd1      259 irq 15     98% idle
> 	xfers   256
> 	Kbyte   510
> 	sec      10
> 
> The performance is so poor that I cannot copy a CD from cd0
> to cd1 at 2x (HP supports writing at 4x).  Copying from cd0
> to wd0 takes ages...
> 
> The (partial) output from 'dmesg' follows
> 
>     NetBSD 1.4.1 (LOGE) #5: Wed Sep 29 00:14:51 CEST 1999
>         root@loge.nibel.net:/usr/src/sys/arch/i386/compile/LOGE
>     cpu0: family 6 model 7 step 3
>     cpu0: Intel Pentium III (686-class)
>     real mem  = 133693440
>     avail mem = 122294272
>     ...
>     cd0 at atapibus0 drive 1: <ASUS CD-S400/A, , V2.1H> type 5 cdrom removable
>     cd0: 32-bits data port
>     cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2
>     wd0 at pciide0 channel 0 drive 0: <QUANTUM FIREBALLP KA6.4>
>     wd0: drive supports 16-sector pio transfers, lba addressing
>     wd0: 6149MB, 13328 cyl, 15 head, 63 sec, 512 bytes/sect x 12594960 sectors
>     wd0: 32-bits data port
>     wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 4, Ultra-DMA mode 3, Ultra-DMA mode 2
>     ...
>     cd1 at atapibus1 drive 0: <Hewlett-Packard CD-Writer Plus 8100, YMW375ECHU, 1.0g> type 5 cdrom removable
>     cd1: 32-bits data port
>     cd1: drive supports PIO mode 3, DMA mode 1
>     wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 2 (using DMA data transfers)
>     cd0(pciide0:0:1): using PIO mode 4, Ultra-DMA mode 2 (using DMA data transfers)
>     cd1(pciide0:1:0): using PIO mode 0, DMA mode 1 (using DMA data transfers)
> 
> 
> Thank you for your help,

> Federico Lupi