On Mon, Mar 29, 1999 at 07:44:36PM -0400, David Maxwell wrote:
> On Mon, Mar 29, 1999 at 01:44:53AM -0800, Don Lewis wrote:
> > On Mar 26, 11:11pm, "Brian C. Grayson" wrote:
> > } Subject: Re: softdep?
> > 
> > }   Here's my pipe-dream reason for the question:
> > }   I've wondered what performance would be like if one made a
> > } homebrew NVRAM (sitting on a parallel port or ISA, rather than
> > } PCI or a SIMM slot) and changed all FFS mounts to be async --
> > 
> > I suspect that parallel port would be too slow and even ISA would
> > hurt performance.  Many (most?) disk writes would need to update
> > NVRAM.  Ideally the NVRAM should be close to main memory speed.
> 
> I don't think ISA would be too bad for speed reasons, all you have to do
> is beat the latency of a disk drive and it should be a win. However, I 
> think PCI is important for another reason. (DMA)

  Yes, but a homebrew PCI card is more expensive than PPort or
ISA.  At least on a grad student's budget!  If I ever get around
to it, I'd definitely make an ISA version first, as
proof-of-concept and to see if it'd even be worth making anything
fancier.

  Brian