Is this an RK05? Can anyone read it?

Graham Toal gtoal at
Thu Jun 16 21:29:36 CDT 2005

There was once a student project to write a multi-tasking operating
system for the PDP11.  Written at Groeningen University in the
Netherlands under the supervision of professor Harry Whitfield,
this O/S had more than a passing resemblance to the classic
mainframe O/S, EMAS, from Edinburgh.

The O/S was thought to be lost apart from small excerpts that were
documented in the project report (online at: )

but a disk pack has turned up which has a fair chance of containing
a working binary and sources.

We think this is an RK05 pack for a PDP11:


Can anyone confirm that?

And is there anyone in the UK who could read the drive?  It may be
in a format that is backwards compatible with one of the DEC O/Ses,
or it may be unreadable at the FS level, just readable at the
block level.  (Which shouldn't be an insurmountable problem, given
the scan of the documentation; also a disk image should pop right
in to one of Bob Supnik's emulators.)

If someone trustworthy in the UK would like to have a go at
reading this drive, the keeper of the disk pack (in Edinburgh,
Scotland) will mail it to you.  It would have to be someone who
I recognise from the list or who would be vouched for by a 
list regular.  As you can imagine we're a little squirrely
about sending the only copy to a stranger, especially in view
of an unfortunate experience we had last year.

This drive probably has not been spun up since 1978 or 79.

If anyone would like to help, please email me at gtoal at



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