Re: SCA SCSI drives for Ultra 1

[Dave McGuire <mcguire%neurotica.com@localhost>]

On Jan 16, 2009, at 9:59 AM, Gabriel J. Michael wrote:
> I'm relatively new to NetBSD, and new to the mailing list.

  Welcome!

> I am considering getting some hard drives for my old Ultra 1  
> Enterprise. It originally had two 4 GB disks, but one has died, and  
> Ebay has some good deals on 18, 36, and 74 GB drives.
>
> My question is this - the Ultra 1 has an SCA SCSI backplane that  
> can support two disks. I know that there are two versions of SCA,  
> SCA-1 and SCA-2, but it's difficult to find information about them,  
> so I am unsure what version the Ultra 1 has (the service manual  
> doesn't say, either), whether they are backward compatible, etc. I  
> don't want to buy a 74 GB disk only to find that it doesn't work in  
> my system.
>
> I also know (from the Wikipedia article) that there are "single- 
> ended" and "low voltage differential" types of SCA - http:// 
> en.wikipedia.org/wiki/Single_Connector_Attachment - but not sure  
> what difference, if any, that makes for me.

  I've never known the difference between SCA-1 and SCA-2; I suspect  
it's minor.  I can tell you, though, that HVD drives are the only  
ones that definitely won't work in your machine.  Single-ended and  
LVD drives will both work.  (I've used both)

  As a very general rule, over the years, SCSI has been very, very  
good about being backward-compatible.  In my experience, the only  
"SCSI thing" that won't talk to any other "SCSI thing" is HVD.  8-bit  
vs. 16-bit, different bus speeds, SE vs. LVD, etc etc...all have  
worked flawlessly for me.

  So, the 74GB (probably 73GB) drive you found, as long as it's not  
HVD, will almost definitely work fine.

> PS - let me say how impressed I am with the hardware support of the  
> sparc64 port! I originally put Debian on this machine, only to find  
> that there is no Linux driver for the Sbus to PCMCIA bridge. So, I  
> decided to install NetBSD. To be honest, it was painful at first (I  
> think coming from stuff like Ubuntu has made me lazy!) - there is  
> no dvorak map in the generic sparc64 kernel, so I had to create my  
> own. But following the very good documentation, I quickly had  
> things up and running. I recompiled the kernel last night to  
> include the nell pcmcia bridge driver, and a few other things, and  
> this morning I am up and running with a pcmcia WiFi card!

  Yes, it's very good stuff.  The sparc64 port had problems for a  
while, but for the past several years it has been absolutely top  
notch.  Stability, performance, hardware support...It's wonderful.

           -Dave

--
Dave McGuire
Port Charlotte, FL