[psas-software] Need some help with choosing the disk the new PowerPC FC

Andrew Greenberg andrew at uad.com
Tue Oct 11 17:26:48 PDT 2005


>Well, it might still be useful; we could keep /boot on that flash, for
>example.

It seems to me that it would be a Good Thing to be able to bring up Linux 
directly from the flash and then switch / to some other device. Is 16 MB 
enough for this?

>We don't have USB2?  I thought we did.

No, unfortunately.

>Finding a DoC PCI-104 adapter is difficult; I found many DoC 
>PC-104/PC-104+ adapters, but nothing for PCI-104.

If you found a PC-104+ to DiskOnChip that would work. It just can't be an 
ISA only... I haven't even found a PC-104+ DoC adapter board so if you can 
point me to it, that'd be great.

>However, if we do find one, DiskOnChip works fine with Linux AFAICT.  It
>is not "direct", because the DoC does block-remapping and wear-levelling
>internally, so that you can just run a normal filesystem on it without
>concern.

Right. And at this point, we might as well just use a CompactFlash card 
without a journaled file system, like we did on the MOPS520 FC... which 
might be cheaper and easier. I think.

Unless, as I mentioned in my previous email, we don't mind spending $600 
for a linear flash card.

>However, JFFS2 also supports DoC just fine.

OK, now I don't understand. How can we run JFFS2 on DoC if it has its own 
translation layer? Don't we then lose the benefits of JFFS2? Or does JFFS2 
somehow reach deep inside the DoC and munge directly with the flash? If 
someone could investigate this, that would be great.

Andrew



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    Andrew Greenberg - andrew at uad.com - 503.788.1343
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