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From: | "Peter S'heeren" <petersh AT pimc DOT be> |
Newsgroups: | comp.os.msdos.djgpp |
Subject: | Re: Writing an OS |
Date: | Wed, 28 Apr 1999 09:37:33 +0200 |
Organization: | EUnet Belgium, Leuven, Belgium |
Lines: | 29 |
Message-ID: | <3726BABD.7C67262@pimc.be> |
References: | <Pine DOT SOL DOT 3 DOT 91 DOT 990427134359 DOT 3388A AT travelers DOT mail DOT cornell DOT edu> <372637F4 DOT 921 AT erols DOT com> |
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To: | djgpp AT delorie DOT com |
DJ-Gateway: | from newsgroup comp.os.msdos.djgpp |
Reply-To: | djgpp AT delorie DOT com |
There's a ATAPI command called "Set CD Speed" and it has opcode 0BBh. You can set the read & write speeds in kB/sec. This is the format of the command: +00 : BYTE 0BBh +01 : BYTE reserved +02 : WORD Read speed in kB/ec +04 : WORD Write speed in kB/sec +05 : BYTE reserved +06 : BYTE reserved +07 : BYTE reserved +08 : BYTE reserved +09 : BYTE reserved +10 : BYTE reserved +11 : BYTE reserved All fields are big endian. I think some drives allow you to change the speed settings the means of the "Mode Select" command (see: Capabilities and Mechanical Status Page, code 2Ah). You've to "Mode Sense" first, however, to check out if the speed fields can be modified. Good luck Peter S'heeren
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