Heathkit H-11 restoration questions - test-drb@ccmp.vtda.org

5 Oct 1999

...
 <> The M8189 was available as two basic versions 
11/23 and the plus.  The
<> primary difference was what it could boot.
<
<I don't think Alison means 11/23 and 11/23plus; the 11/23 uses a
<dual-height M8186 (KDF11-A) board.  But the M8189 was used in both
<11/23plus (BA11-N box, IIRC) and microPDP11/23 (BA23 box).  The difference
<was just the boot ROMs, as she said.

No I meant what I said.

 M8186 KDF-11A   11/23      No serial or boot/diag roms
   Depending on rev either 18bit or 22bit (if no MMU then 16bit)

 M8189 KDF-11BA  11/23B     serial + boot diag roms. No MSCP boot.
 M8189 KDF-11BB  11/23+     Same board different boot roms. Boots MSCP
   Both are Q22 though early versions were packaged as Q18 
You might want to look at your original quote again, Allison.  It
sounds like you claim you said "The M8189 was available as two versions,
the M8186 and the M8189".  Isn't that like saying "The Mercedes is
available as two versions, the Mercedes and the Chrysler"?  Yeah, sure,
they might share some things in common, but they *aren't* the same
board by any stretch of the imagination!

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