David Empson wrote:
> At the very least, you won't get full performance out of a CD-ROM drive
> faster than 1x, due to the limited throughput of the Apple II SCSI
> cards.  The original SCSI card can't even sustain the throughput
> required for 1x, but the high-speed SCSI card might be able to manage 2x
> (under GS/OS).

I saw dramatic improvement over the 1X drive.
In testing, a CD-600 is 4.5X as fast a CD-150.

I have a CD-150, CD-300,and CD-600 drive and did a little testing.
This is a ROM 01 GS (no accelerator)., and HS SCSI card.
Rev C SCSI should be about the same as HS SCSI with no DMA.
I was surprised that the CD-600 was faster than my hard drive.

These are times for an 8200 block verify under GSOS 6.01
This is without DMA, should be comparable to Rev C SCSI.
(Speed) Drive  -  No DMA Time  - Calc Speed
(1X) CD-150  - 70s  - 60kB/s
(2X) CD-300  - 55s  - 76kB/s
(4X) CD-600  - 53s  -  79kB/s
2GB hard drive 64k block - 480s  - 70kB/s

These are times for a 65535 block verify under GSOS 6.01
This is with DMA.
(Speed) Drive  -  DMA Time  - Calc Speed
(1X) CD-150  - 362s  - 93kB/s
(2X) CD-300  - 103s  - 326kB/s
(4X) CD-600  - 80s  -  420kB/s
2GB hard drive 64k block - 120s  - 280kB/s

The difference is quite noticeable.
That's why I was looking for a driver to support the extra functions on the
CD-600.
I didn't want to go back to the CD-150.

Besides, the missing CD-audio functions, the only difference I've noticed is
no OA-E eject.
(You have to push the button.)
I think one of the faqs talked about having to reboot on a change of CDs.
I have NOT seen that.

Joel