The TOPS-20 operating system by {DEC} -- the second proprietary OS
for the PDP-10 -- preferred by most PDP-10 hackers over TOPS-10 (that
is, by those who were not {ITS} or {WAITS} partisans). TOPS-20 began
in 1969 as Bolt, Beranek & Newman's TENEX operating system using
special paging hardware. By the early 1970s, almost all of the
systems on the ARPANET ran TENEX. DEC purchased the rights to TENEX
from BBN and began work to make it their own. The first in-house code
name for the operating system was VIROS (VIRtual memory Operating
System); when customers started asking questions, the name was
changed to SNARK so DEC could truthfully deny that there was any
project called VIROS. When the name SNARK became known, the name was
briefly reversed to become KRANS; this was quickly abandoned when
someone objected that krans meant `funeral wreath' in Swedish (though
some Swedish speakers have since said it means simply `wreath'; this
part of the story may be apocryphal). Ultimately DEC picked TOPS-20
as the name of the operating system, and it was as TOPS-20 that it
was marketed. The hacker community, mindful of its origins, quickly
dubbed it TWENEX (a contraction of `twenty TENEX'), even though by
this point very little of the original TENEX code remained
(analogously to the differences between AT&T V6 Unix and BSD). DEC
people cringed when they heard "TWENEX", but the term caught on
nevertheless (the written abbreviation `20x' was also used). TWENEX
was successful and very popular; in fact, there was a period in the
early 1980s when it commanded as fervent a culture of partisans as
Unix or ITS -- but DEC's decision to scrap all the internal rivals to
the {VAX} architecture and its relatively stodgy VMS OS killed the
DEC-20 and put a sad end to TWENEX's brief day in the sun. DEC
attempted to convince TOPS-20 users to convert to {VMS}, but instead,
by the late 1980s, most of the TOPS-20 hackers had migrated to Unix.
There is a TOPS-20 home page.
[glossary]
[Reference(s) to this entry by made by: {operating system}{TOPS-10}{TOPS-20}]