[rescue] hard drives for sparc10?

[Joshua Boyd]

On Tue, Jan 18, 2005 at 03:59:42PM +0000, Peter Corlett wrote:
> Joshua Boyd  <jdboyd at jdboyd.net> wrote:
> > On Tue, Jan 18, 2005 at 10:55:33AM +0000, Peter Corlett wrote:
> [...]
> >> Surprisingly, the drive's more reliable on the SCSI bus than when
> >> it was on IDE, despite me not using goats and black candles.
> > Err, isn't that a relatively old (more than a year? Two years?)
> > drive though?
> 
> I have a faint memory that it was bought in April 2003. However why
> would more recent drives suddenly become more incompatible? I'd expect
> them to migrate closer to the SCSI spec if anything.

If the Acard firmware changelogs are anything to go by, they are still
circling around without actually getting closer, and new exceptions in
every vector.  Now if only I could find those files again, I'd point out
what I mean.  They seem to no longer be keeping links to the changes
next the download though.  Grr.
 
> That's interesting if true, but I'd want to see a reference before I
> believe it.

http://www.lsilogic.com/files/docs/marketing_docs/storage_stand_prod/Technology/sata_compatability.pdf

http://www.lsilogic.com/technologies/industry_standards/sas.html
 

> /dev/sda:
>  Timing cached reads:   3832 MB in  2.00 seconds = 1916.00 MB/sec
>  Timing buffered disk reads:  184 MB in  3.01 seconds =  61.13 MB/sec

So, as I said, certainly fast enough for uncompressed video, possibly
fast enough for dual stream uncompressed depending on the format.

Assuming 720x486, RGB wouldn't quite truly work, but with caching may be
reasonably fakeable (you need 32megs a second.  If you cache a seconds
worth of both streams, then you could probably pull off something like
10 seconds of playback before you can't keep up anymore).

RGBA won't work.  
8bit YUV 4:2:2 will work (the prefered format on an O2 anyway).
v210 YUV probably won't work (each stream is 28megs a second), but is
even easier to fake than RGB.

Of course, on an O2, the disk would be maxed at 40megs/sec (less really
in the real world due to overhead) anyway due to UW-SCSI speed, so two
drives (the second on a PCI card) would be needed anyway.

I have a 711 array that I was hoping to find the money to fill with 36
gigs drives, but ever since seeing the 7730, I've been thinking that a
7730 and SATA drive would be cheaper than filling the 711.

-- 
Joshua D. Boyd
jdboyd at jdboyd.net
http://www.jdboyd.net/
http://www.joshuaboyd.org/