Network Working Group                                    John R. Pickens
RFC # 485                                                UCSB
NIC # 15063                                              19 March 1973
References NWG/RFC #473


                         MIX and MIXAL at UCSB

The following, in response to David Walden's MIX query (RFC#473) was
written by a graduate student at UCSB.  Questions regarding "cheap"
usage should be directed to Roland F. Bryan (RFB) at UCSB.
-----------------------------------------------------------------------

Mark Scott Johnson
18 March 1973

    I wrote a MIXAL assembler and a MIX simulator last summer.  The
assembler is written in SNOBOL4 and, unfortunately, is fairly expensive
to run.  The assembler has been fairly well debugged and is documented.
However, although the MIX simulator is written (in 360 Assembler), it
has only been partially debugged.  Due to the resumption of school and
other commitments, I was unable to give the simulator a thorough
debugging.  All the simulated instructions except I/O instructions have
been tested somewhat and appear to be operating well.  Also, card reader
input and printer output are operational, but my simulation of disk
files and magnetic tape has not been completed.  There is presently no
documentation for the simulator.  Very little documentation is needed,
however, since the simulator follows almost to the letter the
specifications detailed in _Fundamental_Algorithms_.

    If anyone is interested in using the assembler and/or the simulator,
I will be happy to supply what documentation exists plus some
information on how the programs can be accessed.  Also, if anyone is
interested in the source code for the programs, I will be happy to send
it.  I hope to be able to finish the simulator this next quarter.  If
anyone wants to use the system and if they should find any bugs, I will
do my best to maintain and correct the programs.





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Pickens                                                         [Page 1]