3 and 4 drives in the empeg

See this potential product. See this thread for some Q&A about it.

From what I gather, it will enable the use of up to 4 physical hard drives on a single IDE channel. It was created for TiVo by the same guy that makes the TurboNet cards. TiVo, like the MkII and MkIIa, only have one IDE channel. This hack would allow more drives from a single controller. Just passing this on as it seems that some of us (Paul Grzelak) could find this useful. If we get FLAC support, it may be essential. The only problem is cramming this interface and 3 to 4 drives into the empeg. But... I think it's still something of interest here.

From that thread:
> How does it look to linux

It looks like one controller (primary) with four drives. They come up as hda, hdb, hdc, and hdd. The only trick is that hdc and hdd normally map to the secondard controller so when you create the dev you have to specify it correctly for the quad configuration, rather than the default 2 controller configuration.

I imagine this comes at the cost of performance, but how fast does a drive need to be to read mp3's into cache...

Nice hack. I've personally never opened up my empeg (come christmas my waranties expire, I'm looking forward to it) but is there really space in there for four drives? I can't imagine there is, but i've been wrong before...

Matthew

Since 40 Gb drives are only 9.5 mm heigh and the maximum harddrive height in the mk2a is 19.5 mm it shoud be possible to fit 4*40 Gb harddrives = 160 Gb at a cheaper price than 2 * 60 Gb

best regards

Ole

Greetings!

I would have concerns about the amount of power that four drives would take on the empeg. Isn't there also some form of masking or changing the drive devices around at the kernel level? I usually have to mess around with hda and hdc... Interesting possibilities, though... Hmmm... That could be nice!!! Pity it doesn't seem to support laptop drives... But...

I agree, power consumption would be a big "if", wouldn't it?

But more importantly, I think that heat would be an even bigger issue.

Isn't there also some form of masking or changing the drive devices around at the kernel level?

IIRC not on the kernel level but when creating the /dev/hd[x] devices.

Normally the drives on the first IDE chain are /dev/hda and hdb, on the second hdc and hdd. Since the MkI had two IDE chains and used the drives as primary on both chains, it used hda and hdc. To simplify coding, the MkII calls what's normally /dev/hdb /dev/hdc instead - by giving the mknod command the parameters (major/minor numbers) that are normally used for /dev/hdb when creating /dev/hdc.

So when addressing the drives by device name, when addressing /dev/hdc a MkII will automatically talk to the slave drive on the first chain, while a MkI will talk to the primary drive on the second chain, because the OS looks up the major/minor numbers from the /dev/hd[x] entry and then talks to the hardware according to the numbers instead of the name.

Or at least that's the way I believe it works...

/Michael