[Info-vax] TECO meta-discussion [was Re: Intel proposal to simplify x86-64]

[Rich Alderson]

=?UTF-8?Q?Jan-Erik_S=c3=b6derholm?= <jan-erik.soderholm at telia.com> writes:

> I must ask (since I have never used TECO).

> What is the unique feature of TECO that cannot be done with some other
> tool(s)?

The other responses to your question have most of it right.  I'm here to start
a meta-discussion.

In the context of c.o.v., of course, there is only a single TECO, but that's
not actually true.

The original (paper) Tape Editor and COrrector--TECO--was a program written by
a user/customer for the PDP-1 systems at BBN and MIT.  That programmer later
moved to DEC.

TECO was useful enough that it was reimplemented on later systems, both by DEC
and by the MIT hackers.  DEC provided a nearly common set of commands for the
PDP-8, PDP-11, and PDP-10 (running the Tops-10 operating system); at MIT, a
separate implementation for the PDP-6 and PDP-10 running the ITS operating
system was created.  (The VMS version grew out of the PDP-11 version, of course.)

One of the features of later TECO implementations is that they are Turing
complete, sopeople wrote functions and complete programs to perform complex
tasks; part of the Tops-10 installation procedure, for example, uses a TECO
program to install user options into the operating system configuration prior
to assembling the sources.

In the mid-1970s, a "real time editing" feature was created in the MIT version.
This included the capability to assign compiled functions ("macros") to
individual keystrokes; a number of people created libraries of such editing
macros for their own use.  An enterprising junior hacker decided to collect all
those libraries, resolve duplications, and make a general library that everyone
could use.  The result was eventually named "EMACS", short for "Editing MACroS".

No other version of TECO has all the features of the MIT PDP-10 version, so no
other TECO could host an EMACS.

Reimplementations of EMACS using Lisp dialects instead of TECO have come to be
the norm.  Perhaps a Lisp implementation of VAX TECO would be of interest...

-- 
Rich Alderson					  news at alderson.users.panix.com
      Audendum est, et veritas investiganda; quam etiamsi non assequamur,
	  omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
									--Galen