Date   : Thu, 03 Mar 2005 00:09:56 +0000
From   : Mike Tomlinson <mike@...>
Subject: Re: Progress on IDE interface

In article <050224225502@...>, Jonathan Graham Harston
<jgh@...> writes

>I've also been trying to get CD-ROM access working. I've plugged
>some working CD-ROM drives in with some test CDs blown with known
>data. With the drives I have I haven't been able to do anything -
>the drives just sit there not responding to anything except
>"Reset".
> 
>In digging around on the Interne I discover that apparently CD-ROM
>drives use a version of IDE/ATA called ATAPI, described as "SCSI
>over IDE/ATA". Essentially, to control a CD-ROM drive you send a
>SCSI command packet over the IDE interface. So, after ripping out
>all the SCSI control code to replace it with IDE control code, it
>turns out that CD-ROMs need SCSI commands.  Grrr...  Anyway, I'm
>still investigating this.

Sorry if I'm a bit late in coming back to this - been away working.
ATAPI devices lie doggo and need a "magic packet"  - a sequence of
certain commands sent over the IDE bus - to wake them up before they
will respond.  Thereafter, talking to them is, like you say, similar to
using SCSI devices.

-- 
.sigmonster on vacation