Matt, First, sorry for the delayed response. In around 1994 through late 1996 I worked on the FlashPort project in Bell Labs. A significant project that we completed was FlashPort'ing the 4ESS SWAP assembler from TSS/360 to Solaris. My memory is that the 4E team wanted to get off of TSS and onto Unix. Alan https://techmonitor.ai/technology/emulator_house_echo_logic_folded_back_int… On Fri, Apr 5, 2024 at 12:59 AM segaloco via TUHS <tuhs(a)tuhs.org> wrote: > So I've been doing a bit of reading on 1A and 4ESS technologies lately, getting > a feel for the state of things just prior to 3B and 5ESS popping onto the scene, > and came across some BSTJ references to the programming environments involved > in the 4ESS and TSPS No. 1 systems. > > The general assembly system targeting the 1A machine language was known as > SPC-SWAP (SWitching Assembly Program)[1](p. 206) and ran under OS/360/370, with > editing typically performed in QED. This then gave way to the EPL (ESS > Programming Language) and ultimately EPLX (EPL eXtra)[2](p. 1)[3](p. 8) > languages which, among other things, were used for later 4ESS work with cross- > compilers for at least TSS/360 by the sounds of it. > > Are there any recollections of attempts by the Bell System to rebase any of > these 1A-targeting environments into UNIX, or by the time UNIX was being > considered more broadly for Bell System projects, was 3B/5ESS technology well on > the way, rendering attempting to move entrenched IBM-based environments for the > older switching computation systems moot? > > For the record, in addition to the evolution of ESS to the 5ESS generation, a > revision of TSPS, 1B, was also introduced which was rebased on the 3B20D > processor and utilized the same 3B cross-compilation SGS under UNIX as other 3B- > targeted applications[4]. Interestingly, the paper on software development > in [4](p. 109) still makes reference to Programmer's Workbench as of 1982, > implying that nomenclature may have still been the norm at some Bell Labs sites > such as Naperville, Illinois, although I can't tell if they're referring to > PWB as in the branch of UNIX or the environment of make, sccs, etc. > > Additionally, is anyone aware of surviving accessible specimens of SWAP > assembly, EPL, or EPLX code or literature beyond the BSTJ references and paper > referenced in the IEEE library below? Thanks for any insights! > > - Matt G. > > [1] - https://bitsavers.org/magazines/Bell_System_Technical_Journal/BSTJ_V58N06_1… > [2] - https://ieeexplore.ieee.org/document/810323 > [3] - https://bitsavers.org/magazines/Bell_System_Technical_Journal/BSTJ_V60N06_1… > [4] - https://bitsavers.org/magazines/Bell_System_Technical_Journal/BSTJ_V62N03_1…