Re: Controlling cd/dvd drive's cache
Re: Controlling cd/dvd drive's cache
- Subject: Re: Controlling cd/dvd drive's cache
- From: email@hidden
- Date: Fri, 13 Jan 2006 10:19:04 -0500 (EST)
- Importance: Normal
Alex (et al),
Thanks for the reply. What I am working on is adding "EAC-like"
functionality (secure cd ripping) to my application
(http://sbooth.org/Max/). In order to perform true error correction and
verify that the audio data is correct, I need to compare multiple reads of
the same sector. Obviously if erroneous data is in the cache then
multiple reads of the same sector will always produce the same result.
Hence the need to either 1) disable the cache or 2) read a block larger
than the cache (2048 on my drive, too large for practical purposes) or 3)
read a sector, flush the cache, re-read the sector, etc. So I am not
writing a device driver per se, just performing some low-level
manipulation.
Stephen
> I am not sure on which level you are looking.
>
> My time in CD-Recording is over for four years now - which is an
> eternity in IT. That said, I am sure the MMC3 command set has
> commands to do all these things.
>
> However, why would you need to do this? If you are writing to the
> device yourself, then you probably came across MMC command sets.
>
> Forcing the cache to be flushed when other applications are writing
> to the device is usually not a good idea.
>
> Alex
>
> Am 13.01.2006 um 16:05 schrieb email@hidden:
>
>> Hello all,
>>
>> I had inquired about this a while back and never got a response, so
>> thought I'd ask again.
>>
>> Is there a way to control the hardware cache on cdrom drives in OS
>> X? For
>> example, I would like to turn caching on/off, force a flush of the
>> cache,
>> etc. It seems there should be an ioctl() to do this. But, all my
>> searching has turned up nothing. What have I missed?
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