I first used a "disassembler" in late 1980, a program that disassembled 8080 machine code into 8080 assembly language.  ( it was called "Resource").  
I recall my first (comic) "disappointment" was that it didn't somehow regenerate the original labels and comments...!!!

This sounds like it:    https://gopherproxy.meulie.net/gopher.floodgap.com/0/archive/walnut-creek-cd-simtel/CPMHELP/RESOURCE.HLP

"RESOURCE Disassembler 
Overall structure 
Sample of RESOURCE usage 
Disassembly steps 
Description of commands 
Watch for... (tips) 
Quick command summary 
ZESOURCE: Extension of RESOURCE 
                 RESOURCE: disassembler for 8080 programs 
                     by Ward Christensen (312) 849-6279 
" RESOURCE commands are inconsistent at best.   - RESOURCE is a kludge based  on 
years of disassembler experience and hacking,  and was never "planned" -  just 
coded sitting at a tube, and modified over 2 years before being contributed to 
the CP/M UG  (1/80).  For example,  to kill a  symbol: k.label but  to kill  a 
control value:  caddr,k and  to kill a comment:  ;addr, but RESOURCE does  the 
job like no other I have seen. 

N-O-T-E: Pardon the editorial,  but I feel hardware  without good software  is 
useless to 99%  of us.  Most  good software has  to be paid  for.  I  strongly 
support the legitimate purchase of licensed software.  I do not regularly  use 
any programs which I have not  purchased.  (Yes, I do occasionally "try"  one, 
but then  buy it  if I  plan on  using it).   I have  been asked  by  software 
businesses to NOT  distribute RESOURCE -  because of it's  ability to  produce 
good .asm source quickly.  But, there are so many disassemblers out, why not a 
good, conversational  one?   Please use  it  in the  spirit  in which  it  was 
contributed:  to  enlarge  your understanding  of  the micro-  computer  world 
around you, and to allow you to customize programs which you legitimately own, 
for your own use. 

                         "Semper non rippus offus" "
=========================================================

Ward Christensen built what I understand was the first computer bulletin-board system, which he called "CBBS", in Chicago.
I became friends with the owner and operator of the second (?) CBBS, called "CBBS-NW", Jim Willing, who lived in Beaverton Oregon in 1980.  

             Jim Bell



On Sunday, January 6, 2019, 12:43:59 PM PST, grarpamp <grarpamp@gmail.com> wrote:


The US National Security Agency will release a free reverse
engineering tool at the upcoming RSA security conference that will be
held at the start of March, in San Francisco. The software's name is
GHIDRA and in technical terms, is a disassembler, a piece of software
that breaks down executable files into assembly code that can then be
analyzed by humans. The NSA developed GHIDRA at the start of the
2000s, and for the past few years, it's been sharing it with other US
government agencies that have cyber teams who need to look at the
inner workings of malware strains or suspicious software. GHIDRA's
existence was never a state secret, but the rest of the world learned
about it in March 2017 when WikiLeaks published Vault7, a collection
of internal documentation files that were allegedly stolen from the
CIA's internal network. Those documents showed that the CIA was one of
the agencies that had access to the tool.