Goals - BCL Molecular 18

BCL Molecular 18
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eM18 - The Molecular 18 Emulator

Not having a working M18 is a rotten shame, and not getting my act together in the late 1990s I didn't hover a few machines up!   We do have a Mk V and a Distributor at the museum, and I am hopeful we might get one working.  We do have the OS and Application disks thankfully.

So, in the mean time let's write an emulator.  (There is a rich history of writing emulators for historic machines - simh being the most famous).

eM18 is written in simple plain C code.  I am not sure what it will run on finally, but it runs well on my development machine and on a tiny (and cheap) Raspberry Pi.

On starting the emulator:

Molecular 18 Emulator

Building processor, 32k core memory, DD1600 disk drive as Unit 70
Loading core image
 Core image read from /home/steve/Documents/mollyimages/coreImage.txt
Loading default disk images
 70 Fixed master27
 70 removeable security26
Creating terminals and printers
 Adding Terminal - /dev/ttyUSB0 - device 50/40
... connected

In the settings file, we specify 32K Words of core and a DD1600 drive with two surfaces at dev 70.
Again in the settings file, device 50/50 is mapped to a serial port.

This is the help screen:

 dc nnn        Display core from nnnnnn or nn/nnnn
 fc nnn        Dump one page to host disk from nnnnnn or nn/nnnn
 ac nnn        Amend  from nnnnnn or nn/nnnn
 cc            Clear  - no warnings
 sc ad sc      Save core from ad (address) to sc (sector)
 lc ad sc      Load core from sc (sector) to ad (address)
 ds nnn        Display sector nnn
 fs nnn        Load/Amend sector
 cs nnn        Clear sector nnn
 ssec          Security Copy
 dp            Display processor state
 s             Display processor stats
 run nnn       Run from PC = nnnnnn or nn/nnnn
 b nnn         Set breakpoint at nnnnnn or nn/nnnn
 step nnn      SingleStep from PC=nnnnnn or nn/nnnn
 b             Boot LOS
 sop           Boot Special OP
 st            Boot single task
 t xxx           Trace On from nnn or nn/nnnn
 . Quit

(C) 2022 Kevin Murrell & The National Museum of Computing
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