NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/sys/ibm/pc/hardware/33505

Internet Message Format | 1992-12-17 | 2.0 KB

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Newsgroups: comp.sys.ibm.pc.hardware,alt.cd-rom
Path: sparky!uunet!mcsun!sun4nl!dutrun!donau!einstein.et.tudelft.nl!eddy
From: [e-mail] (J.G.E. Olk)
Subject: Problems with Philips CM50 CDROM player on fast PCs
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Organization: Delft University of Technology, Dept. of Electrical Engineering
Date: Thu, 17 Dec 1992 12:45:23 GMT
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Anyone got a solution to get the Philips CM50 CDROM player and the
proprietary interface card working on a fast machine?

The problem I experience with it is that reading a CDROM does not work
on all machines (I tried quite a few), the audio control stuff does however.
Especially on 486 machines (ISA or EISA) the CM50 won't read CDROMs,
disabling (all) caches doesn't help. On a 386DX/33 it works more or
less, although there are occasional read errors and, strangely enough,
lowering the CPU clock speed to 8MHz also puts the CM50 out of order.
On a 4.77/9.54 MHz V20 XT it works like a charm and switching the CPU
clock doesn't give any troubles.

I'm almost sure there is a problem in the PHILIPS.SYS device driver,
most likely with the DMA stuff to read the CDROM. I suspect there must
be some sort of relation between the CPU speed and the DMA transfer
speed. The PHILIPS.SYS I use is version 1.03, Oct. 1991.
Perhaps someone knows of a newer version?

Furthermore, I'd be very happy if someone could provide me with info
on the properietary interface so I can write my own DOS/Linux device
driver.

Thanks,
- Eddy
--
\  Eddy Olk                          Section Computer Architecture         \
/  email: [e-mail]  Department of Electrical Engineering  /
\  phone: [phone]              Delft University of Technology        \
/                                    The Netherlands                       /