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SCSI2SD (Part 2 of Resurrecting the VAXen)

Link to Part 1

Almost all my SCSI drives have died.  This is the way of things, I suppose.  Replacements are difficult and expensive to find, and will probably not last much longer anyhow.

Looking for alternatives, I found SCSI2SD, that emulates a hard disk using MicroSD cards as the backing store.  Someone’s already got it working with a MicroVAX 3100 and VMS (at least, so says the page).  I’ve got a pile of extra MicroSD cards (I seem to get one with every new phone!), so it seems like a good thing.

SCSI2SD_V3.0_plainThe operation of the card is fairly self explanatory.  There’s a slot for a MicroSD card and a port for a Micro USB connector.  The card is configured by a custom application running on Linux, Windows, or Mac OS X.  A bank of resistors provides termination (I promptly removed them since I have external drives I’d like to attach).


The pre-compiled version from the website would not run on Fedora 22.  Luckily, the complete source (as well as schematics) are provided.  The GUI is fairly intuitive with a few exceptions:

  • If your resolution is not high enough, the “Save to Device” button can be hidden.  This took me an embarrassingly long time to figure out.
  • The input on the Device Size auto updates.  You can edit the field, but it’s acts weird.  Entering in a sector count works much better.

It’s possible (although I have not tested it) to carve up a big MicroSD card into multiple SCSI targets, providing the illusion of multiple drives.  This should be useful on the VAXStation 3100, which cannot boot from drives larger that 1 GB.

After configuring the card, I cabled it up to my VAXstation 4000/60:

>>> show dev

  -------      ----      -------    --------     -----    --    ------      ---
  ESA0         08-00-2B-1D-84-06
  DKA0         A/0/0     DISK         1.97GB      FX                         4.2
 ..HostID..    A/6       INITR

Hot damn!