UniBone: Linux-to-DEC-UNIBUS-bridge, year #1

W2HX w2hx at w2hx.com
Sat Nov 16 18:56:29 CST 2019

Is the BBB not fast enough to do Qbus? Meaning, for qbus, would a FPGA be necessary? Or was this just the op's choice among many possible options? 

It does seem useful to have this thing run linux and ethernet and be able to pass files (data and programs) back and forth very easily. the FPGA approach seems more technically challenging but seems less universal (to my limited mind).  It would seem a BBB you could load software, test, and reload as easily as copying some executable code (I dont know if that is correct or an over simplification). whereas the FPGA sounds like it needs to be recompiled/re-burned each time?

I dont know whether an RPi could work or if the BBB is needed for speed etc.


From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Jörg Hoppe via cctalk <cctalk at classiccmp.org>
Sent: Saturday, November 16, 2019 12:45 PM
To: Stefan Skoglund; General Discussion: On-Topic and Off-Topic Posts; General Discussion: On-Topic Posts
Subject: Re: UniBone: Linux-to-DEC-UNIBUS-bridge, year #1

>> *What it is:*
>> In case you forgot: UniBone is a plugin board to DEC PDP-11 UNIBUS
>> systems containing a BeagleBone Black.
>> See http://retrocmp.com/projects/unibone.
>> This combo can simulate PDP-11 devices embedded in a physical
>> machine.
>> So you can operate and repair incomplete UNIBUS PDP-11s and even
>> VAXes,
>> just by emulating the missing parts.
>> Disk drive emulators accept SimH image files, which can be ftp'd to
>> the
>> emulator (no SDcard changing!).
> Ethernet or FC connection ??
> If so it would be possible to build an PDP-11 who is datacenter-
> compatible today year 2019 ...
> One requirement for todays datacenter (for some owners at least) is the
> ability to directly connect the system to the storage system (ie
> Hint: with that requirement as far as i know it an ARM device in the
> form of a Samsung S9 can't be data center compatible....
Mot clear to me what "data center compatibility" for a PDP-11 means.

Anyhow, the BeagleBone runs Debian Linux, has an Ethernet port and the
emulation software is a plain Linux application.
So all emulator binaries and all PDP-11 disk images or other data can
reside anwhere in the world and are not bound to the UniBone SDcard.


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