Re: IDE/ATAPI in 2.5

[Joerg Schilling]

>From: "Richard B. Johnson" <[e-mail]>
>> >From [e-mail] Fri Jul 12 22:18:47 2002
>> 
>> >As much as I hate IDE, IDE isn't going away. All my systems use SCSI
>> >so on machines that have CD/ROMS, I use your libraries and your tools.
>> 
>> >Maybe somebody should make CD/ROM code that directly talks to IDE via
>> >/dev/hdwhatever, instead of expecting you to modify your code that
>> >has worked so well for so long.
>> 
>> This would be a really bad idea.
>> 
>> Such a change would force me to add a 6th (and unneeded) new interface.
>> Why? What problem would be solved if you did introduce such an interface?
>> 

>Well for one thing it eliminates the requirement to
>include SCSI interface code on machines that don't
>have SCSI. That's the practical aspect.

>Now, the esoteric. Do you truly think that it is
>proper to encapsulate devices in various layers?

>The IDE interface, if it wasn't for the bug-workarounds,
>is just a floppy disk interface that uses a different
>controller chip. It is register-based, not message-
>based. If you throw in a message-based control layer
>(SCSI), what problems are you solving? It's a
>rhetorical question. No answer is required.

If you like to use the floppy only via the ATA registers, then
you don't like to be able to format media?

BTW: the overhead to set up DMA is higher than the overhead to set up a SCSI 
CDB.

Jörg

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