From:	"Peter S'heeren" <petersh AT pimc DOT be>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Writing an OS
Date:	Wed, 28 Apr 1999 09:50:13 +0200
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Sorry, this one should be under "ATAPI command for CD speed change"
fromWolfgang Hesseler ...

Peter S'heeren wrote:

> 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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