Solid State Disk replacement for RD53, 54, RK05, RL02/02 - test-drb@ccmp.vtda.org

11 Mar 2010

"Zane H. Healy" <healyzh at aracnet.com> wrote:

...
  On Wed, 10 Mar 2010, e.stiebler wrote:

  > Zane H. Healy wrote:
 >
>> >>> OTOH, they old ones show up on ebay frequently, and they are not
that 
>> >>> expensive.
> >> 
> >> What "old ones" show up on eBay?
 >
 > The "usual" suspects like cmd, dilog, emulex ?
 > OK, in all honesty I didn't check for more than a year, but they showed up 
 > before, that's why I canceled my design ...  
 Okay, old 3rd party disk controllers.  The problem with these is that they
 also require old hard drives.  I'm also slightly surprised to hear mention
 of CMD controllers that aren't expensive, but then I've not looked for such
 things in years. 
Huh? New SCSI disks works just as well.
The biggest problem might be that some OSes gets confused by really big 
disks. With RSX for instance, the device driver used to have a bug so 
that disks larger than 8 Gig didn't work right. The size got masked to 
24 bits... With M+ 4.6, the system instead caps the disk size at 8 Gig 
if the disk is larger, unless you switch to 32 bit LBNs.

The only other problem with SCSI disks is that you might need to get 
adapters for the old style 50 pin connectors.

However, as long as we talk plain SCSI, and not differential, or 
something else odd, it is still just fine being backward compatible...

...
  My PDP-11's are using 1" High 3.5" SCSI
Hard Drives, it does wonders for the
 noise level, and helps with the power consumption, but I'm honestly a bit
 worried about their long term viability.  At least I have a much larger
 supply of SCSI drives I can use than I do MFM Hard Drives (and yes, I have a
 few of those, and a couple ESDI drives). 
I'm using second, or if it is third generation storage work disks for my 
machines. Blue boxes. Pretty. And I can put seven of them in one unit. 
Actually, I only have five in there, along with a DAT-3 tape unit, and 
an Exabyte externally.

...
  Of course the other thing I worry about is power
supplies.  In fact that's
 what I've been loosing VMS boxes to.  :-(  
Power supplies for the PDP-11s? Yes, that is always a possible 
problem... And a bigger one than disks, I'd say.

	Johnny