optcd

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

This is the README file for the Optics Storage 8000 AT CDROM device driver.

This is the driver for the so-called 'DOLPHIN' drive, with the 34-pin
Sony-compatible interface. For the IDE-compatible Optics Storage 8001
drive, you will want the ATAPI CDROM driver. The driver also seems to
work with the Lasermate CR328A. If you have a drive that works with
this driver, and that doesn't report itself as DOLPHIN, please drop me
a mail.

The support for multisession CDs is in ALPHA stage. If you use it,
please mail me your experiences. Multisession support can be disabled
at compile time.

You can find some older versions of the driver at
      dutette.et.tudelft.nl:/pub/linux/
and at Eberhard's mirror
      ftp.gwdg.de:/pub/linux/cdrom/drivers/optics/

Before you can use the driver, you have to create the device file once:
 # mknod /dev/optcd0 b 17 0

To specify the base address if the driver is "compiled-in" to your kernel,
you can use the kernel command line item (LILO option)
             optcd=0x340
with the right address.

If you have compiled optcd as a module, you can load it with
 # insmod /usr/src/linux/modules/optcd.o
or
 # insmod /usr/src/linux/modules/optcd.o optcd=0x340
with the matching address value of your interface card.

The driver employs a number of buffers to do read-ahead and block size
conversion. The number of buffers is configurable in optcd.h, and has
influence on the driver performance. For my machine (a P75), 6 buffers
seems optimal, as can be seen from this table:

#bufs	kb/s	%cpu
1	97	0.1
2	191	0.3
3	188	0.2
4	246	0.3
5	189	19
6	280	0.4
7	281	7.0
8	246	2.8
16	281	3.4

If you get a throughput significantly below 300 kb/s, try tweaking
N_BUFS, and don't forget to mail me your results!

I'd appreciate success/failure reports. If you find a bug, try
recompiling the driver with some strategically chosen debug options
(these can be found in optcd.h) and include the messages generated in
your bug report. Good luck.

Leo Spiekman ([e-mail])