* [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? @ 2023-09-26 1:24 segaloco via TUHS 2023-09-26 1:37 ` [TUHS] " Jon Steinhart ` (3 more replies) 0 siblings, 4 replies; 14+ messages in thread From: segaloco via TUHS @ 2023-09-26 1:24 UTC (permalink / raw) To: The Eunuchs Hysterical Society Hello, my studies lately bring me to the question: Are there any extant examples of telephone switching software, built on UNIX, from the various parts of the Bell System prior to the introduction of the 5ESS and 3B20D? My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in active use, that sleeping dragon can lie. What's gotten me curious is reading about 1ESS in a BSTJ volume I picked up, noting the particulars on how previous concerns of manual and electro-mechanical systems were abstracted into software. Even without surviving examples, were previous systems such as the 1ESS central control ever ported to or considered for porting to UNIX, or was the hardware interface to the telco lines too specific to consider a future swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS (switching, not source code) also comes to mind, although all I know that survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. By the way, it's funny, I have UNIX to thank for my current experiments with telephones and other signalling stuff, what with making me study the Bell System more generally. It's starting to come full circle in that I want to take a crack at reading dialing, at least pulse, into some sort of software abstraction on a SBC that can, among other things, provide a switching service on top of a UNIX-like kernel. I don't know what I'd do with such a thing other than assign work conference call rooms their own phone numbers to dial with a telephone on a serial line...but if I can even get that far I'd call it a success. One less dependency on the mobile... - Matt G. ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:24 [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? segaloco via TUHS @ 2023-09-26 1:37 ` Jon Steinhart 2023-09-27 2:46 ` Heinz Lycklama 2023-09-26 1:39 ` Jon Steinhart ` (2 subsequent siblings) 3 siblings, 1 reply; 14+ messages in thread From: Jon Steinhart @ 2023-09-26 1:37 UTC (permalink / raw) To: The Eunuchs Hysterical Society segaloco via TUHS writes: > Hello, my studies lately bring me to the question: Are there any extant > examples of telephone switching software, built on UNIX, from the various > parts of the Bell System prior to the introduction of the 5ESS and 3B20D? > My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in > active use, that sleeping dragon can lie. > > What's gotten me curious is reading about 1ESS in a BSTJ volume I > picked up, noting the particulars on how previous concerns of manual and > electro-mechanical systems were abstracted into software. Even without > surviving examples, were previous systems such as the 1ESS central > control ever ported to or considered for porting to UNIX, or was the > hardware interface to the telco lines too specific to consider a future > swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS > (switching, not source code) also comes to mind, although all I know that > survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > By the way, it's funny, I have UNIX to thank for my current experiments > with telephones and other signalling stuff, what with making me study the > Bell System more generally. It's starting to come full circle in that I > want to take a crack at reading dialing, at least pulse, into some sort > of software abstraction on a SBC that can, among other things, provide a > switching service on top of a UNIX-like kernel. I don't know what I'd do > with such a thing other than assign work conference call rooms their own > phone numbers to dial with a telephone on a serial line...but if I can even > get that far I'd call it a success. One less dependency on the mobile... > > - Matt G. Heinz might know something about this. If I remember correctly, one of the projects in his group was SS1, an all-digital exchange. I have some vague memory of him and Carl poring over some gigantic switch statement looking for a bug - the long distance code wasn't sending the ST pulse and as a result all of the key pulse senders at the Berkeley Heights telephone exchange were taken off line and needed a technician to go in and manually reset them. They were not amused. Fortunately, they and BTL were both children of Ma Bell. If my memory serves me correctly, the system had a pair of PDP-11/10s that ran Hal Alles's digital filter code, a PDP11/70 behind the whole thing, Harry Breece's active replacement circuitry for the hybrid transformers, and some huge insanely fast wire-wrapped boards designed by John Sheets that did TDM switching. Jon ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:37 ` [TUHS] " Jon Steinhart @ 2023-09-27 2:46 ` Heinz Lycklama 2023-10-04 6:52 ` Kevin Bowling 0 siblings, 1 reply; 14+ messages in thread From: Heinz Lycklama @ 2023-09-27 2:46 UTC (permalink / raw) To: tuhs [-- Attachment #1: Type: text/plain, Size: 4035 bytes --] To answer Jon's following question (2 minutes later): ------------------------------------------------------------------------ Oh yeah, and I think that this is why Heinz wrote MERT, but he should know more than me about it. ------------------------------------------------------------------------ Yes, my Dept. in MH was involved in the early days of digital switching and the need for real-time response was certainly recognized. But MERT was not developed with a specific telephony project in mind. I was mostly involved in software in support of current projects being done in the Dept. We started the MERT project at the time that DEC announced their PDP-11/45 mini-computer in the early 1970's because it supported 3 separate address spaces - system, supervisor, and user. This enabled us to run operating system environments with different user application program needs, specifically real-time under control of one supervisor and time-sharing applications in another supervisor, to start with. Hence its name - Multi-Environment Real Time (MERT). Once we had MERT up and running on the PDP-11/45 and PDP-11/70 computers, some projects in other Bell Labs locations involved in telephony projects started building their projects on the MERT system. The DMERT system was developed later on by projects at yet another Bell Labs location. Heinz On 9/25/2023 6:37 PM, Jon Steinhart wrote: > segaloco via TUHS writes: >> Hello, my studies lately bring me to the question: Are there any extant >> examples of telephone switching software, built on UNIX, from the various >> parts of the Bell System prior to the introduction of the 5ESS and 3B20D? >> My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in >> active use, that sleeping dragon can lie. >> >> What's gotten me curious is reading about 1ESS in a BSTJ volume I >> picked up, noting the particulars on how previous concerns of manual and >> electro-mechanical systems were abstracted into software. Even without >> surviving examples, were previous systems such as the 1ESS central >> control ever ported to or considered for porting to UNIX, or was the >> hardware interface to the telco lines too specific to consider a future >> swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS >> (switching, not source code) also comes to mind, although all I know that >> survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. >> >> By the way, it's funny, I have UNIX to thank for my current experiments >> with telephones and other signalling stuff, what with making me study the >> Bell System more generally. It's starting to come full circle in that I >> want to take a crack at reading dialing, at least pulse, into some sort >> of software abstraction on a SBC that can, among other things, provide a >> switching service on top of a UNIX-like kernel. I don't know what I'd do >> with such a thing other than assign work conference call rooms their own >> phone numbers to dial with a telephone on a serial line...but if I can even >> get that far I'd call it a success. One less dependency on the mobile... >> >> - Matt G. > Heinz might know something about this. If I remember correctly, one of the > projects in his group was SS1, an all-digital exchange. I have some vague > memory of him and Carl poring over some gigantic switch statement looking > for a bug - the long distance code wasn't sending the ST pulse and as a > result all of the key pulse senders at the Berkeley Heights telephone > exchange were taken off line and needed a technician to go in and manually > reset them. They were not amused. Fortunately, they and BTL were both > children of Ma Bell. > > If my memory serves me correctly, the system had a pair of PDP-11/10s that > ran Hal Alles's digital filter code, a PDP11/70 behind the whole thing, > Harry Breece's active replacement circuitry for the hybrid transformers, > and some huge insanely fast wire-wrapped boards designed by John Sheets > that did TDM switching. > > Jon [-- Attachment #2: Type: text/html, Size: 4536 bytes --] ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-27 2:46 ` Heinz Lycklama @ 2023-10-04 6:52 ` Kevin Bowling 2023-10-05 14:19 ` Kevin Bowling 0 siblings, 1 reply; 14+ messages in thread From: Kevin Bowling @ 2023-10-04 6:52 UTC (permalink / raw) To: heinz; +Cc: tuhs On Tue, Sep 26, 2023 at 7:46 PM Heinz Lycklama <heinz@osta.com> wrote: > > To answer Jon's following question (2 minutes later): > ________________________________ > Oh yeah, and I think that this is why Heinz wrote MERT, > but he should know more than me about it. > ________________________________ > Yes, my Dept. in MH was involved in the early days of digital switching > and the need for real-time response was certainly recognized. > But MERT was not developed with a specific telephony project in mind. > I was mostly involved in software in support of current projects > being done in the Dept. We started the MERT project at the > time that DEC announced their PDP-11/45 mini-computer in > the early 1970's because it supported 3 separate address > spaces - system, supervisor, and user. This enabled us to > run operating system environments with different user > application program needs, specifically real-time under > control of one supervisor and time-sharing applications > in another supervisor, to start with. Hence its name - > Multi-Environment Real Time (MERT). Once we had MERT up > and running on the PDP-11/45 and PDP-11/70 computers, some > projects in other Bell Labs locations involved in telephony projects > started building their projects on the MERT system. The > DMERT system was developed later on by projects at yet > another Bell Labs location. I don't have access to IEEE but there is a paper on MERT https://ieeexplore.ieee.org/document/6770410. The 3B20D and DMERT are also cronicaled in the BSTJ, I have hard copies of that but it should be on IEEE. There is a lot of detail on the 3B20D and 3B21D in the 254 BSPs as well as some coverage of UNIX RTR https://www.telecomarchive.com/plant-all.html. There is more coverage of the 3B20 elsewhere, for instance https://dl.acm.org/doi/pdf/10.1145/1500412.1500418. Wing N. Toy, one of the hardware engineers, published some nice books that tangentially touch on these designs but contain a lot of great microcoding knowledge. Regards, Kevin > Heinz > > On 9/25/2023 6:37 PM, Jon Steinhart wrote: > > segaloco via TUHS writes: > > Hello, my studies lately bring me to the question: Are there any extant > examples of telephone switching software, built on UNIX, from the various > parts of the Bell System prior to the introduction of the 5ESS and 3B20D? > My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in > active use, that sleeping dragon can lie. > > What's gotten me curious is reading about 1ESS in a BSTJ volume I > picked up, noting the particulars on how previous concerns of manual and > electro-mechanical systems were abstracted into software. Even without > surviving examples, were previous systems such as the 1ESS central > control ever ported to or considered for porting to UNIX, or was the > hardware interface to the telco lines too specific to consider a future > swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS > (switching, not source code) also comes to mind, although all I know that > survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > By the way, it's funny, I have UNIX to thank for my current experiments > with telephones and other signalling stuff, what with making me study the > Bell System more generally. It's starting to come full circle in that I > want to take a crack at reading dialing, at least pulse, into some sort > of software abstraction on a SBC that can, among other things, provide a > switching service on top of a UNIX-like kernel. I don't know what I'd do > with such a thing other than assign work conference call rooms their own > phone numbers to dial with a telephone on a serial line...but if I can even > get that far I'd call it a success. One less dependency on the mobile... > > - Matt G. > > Heinz might know something about this. If I remember correctly, one of the > projects in his group was SS1, an all-digital exchange. I have some vague > memory of him and Carl poring over some gigantic switch statement looking > for a bug - the long distance code wasn't sending the ST pulse and as a > result all of the key pulse senders at the Berkeley Heights telephone > exchange were taken off line and needed a technician to go in and manually > reset them. They were not amused. Fortunately, they and BTL were both > children of Ma Bell. > > If my memory serves me correctly, the system had a pair of PDP-11/10s that > ran Hal Alles's digital filter code, a PDP11/70 behind the whole thing, > Harry Breece's active replacement circuitry for the hybrid transformers, > and some huge insanely fast wire-wrapped boards designed by John Sheets > that did TDM switching. > > Jon > > ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-10-04 6:52 ` Kevin Bowling @ 2023-10-05 14:19 ` Kevin Bowling 0 siblings, 0 replies; 14+ messages in thread From: Kevin Bowling @ 2023-10-05 14:19 UTC (permalink / raw) To: heinz; +Cc: tuhs On Tue, Oct 3, 2023 at 11:52 PM Kevin Bowling <kevin.bowling@kev009.com> wrote: > > On Tue, Sep 26, 2023 at 7:46 PM Heinz Lycklama <heinz@osta.com> wrote: > > > > To answer Jon's following question (2 minutes later): > > ________________________________ > > Oh yeah, and I think that this is why Heinz wrote MERT, > > but he should know more than me about it. > > ________________________________ > > Yes, my Dept. in MH was involved in the early days of digital switching > > and the need for real-time response was certainly recognized. > > But MERT was not developed with a specific telephony project in mind. > > I was mostly involved in software in support of current projects > > being done in the Dept. We started the MERT project at the > > time that DEC announced their PDP-11/45 mini-computer in > > the early 1970's because it supported 3 separate address > > spaces - system, supervisor, and user. This enabled us to > > run operating system environments with different user > > application program needs, specifically real-time under > > control of one supervisor and time-sharing applications > > in another supervisor, to start with. Hence its name - > > Multi-Environment Real Time (MERT). Once we had MERT up > > and running on the PDP-11/45 and PDP-11/70 computers, some > > projects in other Bell Labs locations involved in telephony projects > > started building their projects on the MERT system. The > > DMERT system was developed later on by projects at yet > > another Bell Labs location. > > I don't have access to IEEE but there is a paper on MERT > https://ieeexplore.ieee.org/document/6770410. The 3B20D and DMERT are > also cronicaled in the BSTJ, I have hard copies of that but it should > be on IEEE. > > There is a lot of detail on the 3B20D and 3B21D in the 254 BSPs as > well as some coverage of UNIX RTR > https://www.telecomarchive.com/plant-all.html. > > There is more coverage of the 3B20 elsewhere, for instance > https://dl.acm.org/doi/pdf/10.1145/1500412.1500418. Wing N. Toy, one > of the hardware engineers, published some nice books that tangentially > touch on these designs but contain a lot of great microcoding > knowledge. I was reviewing this book https://archive.org/details/computerhardware0000toyw and it is one of the best computer architecture books I've seen. Somehow in 400 pages the authors manage to cover logic, language implementation, compilation, instruction set design, various aspects of operating systems design, and fault tolerance citing timeless pedagogical hardware (PDP11, VAX, S/370, System/38, iAPX-432, WE32000) and software (VMS, UNIX, DMERT). Readers of this list will enjoy it! > Regards, > Kevin > > > > Heinz > > > > On 9/25/2023 6:37 PM, Jon Steinhart wrote: > > > > segaloco via TUHS writes: > > > > Hello, my studies lately bring me to the question: Are there any extant > > examples of telephone switching software, built on UNIX, from the various > > parts of the Bell System prior to the introduction of the 5ESS and 3B20D? > > My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in > > active use, that sleeping dragon can lie. > > > > What's gotten me curious is reading about 1ESS in a BSTJ volume I > > picked up, noting the particulars on how previous concerns of manual and > > electro-mechanical systems were abstracted into software. Even without > > surviving examples, were previous systems such as the 1ESS central > > control ever ported to or considered for porting to UNIX, or was the > > hardware interface to the telco lines too specific to consider a future > > swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS > > (switching, not source code) also comes to mind, although all I know that > > survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > > > By the way, it's funny, I have UNIX to thank for my current experiments > > with telephones and other signalling stuff, what with making me study the > > Bell System more generally. It's starting to come full circle in that I > > want to take a crack at reading dialing, at least pulse, into some sort > > of software abstraction on a SBC that can, among other things, provide a > > switching service on top of a UNIX-like kernel. I don't know what I'd do > > with such a thing other than assign work conference call rooms their own > > phone numbers to dial with a telephone on a serial line...but if I can even > > get that far I'd call it a success. One less dependency on the mobile... > > > > - Matt G. > > > > Heinz might know something about this. If I remember correctly, one of the > > projects in his group was SS1, an all-digital exchange. I have some vague > > memory of him and Carl poring over some gigantic switch statement looking > > for a bug - the long distance code wasn't sending the ST pulse and as a > > result all of the key pulse senders at the Berkeley Heights telephone > > exchange were taken off line and needed a technician to go in and manually > > reset them. They were not amused. Fortunately, they and BTL were both > > children of Ma Bell. > > > > If my memory serves me correctly, the system had a pair of PDP-11/10s that > > ran Hal Alles's digital filter code, a PDP11/70 behind the whole thing, > > Harry Breece's active replacement circuitry for the hybrid transformers, > > and some huge insanely fast wire-wrapped boards designed by John Sheets > > that did TDM switching. > > > > Jon > > > > ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:24 [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? segaloco via TUHS 2023-09-26 1:37 ` [TUHS] " Jon Steinhart @ 2023-09-26 1:39 ` Jon Steinhart 2023-09-26 1:50 ` Andrew Hume 2023-09-26 2:20 ` Kevin Bowling 3 siblings, 0 replies; 14+ messages in thread From: Jon Steinhart @ 2023-09-26 1:39 UTC (permalink / raw) To: The Eunuchs Hysterical Society Oh yeah, and I think that this is why Heinz wrote MERT, but he should know more than me about it. ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:24 [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? segaloco via TUHS 2023-09-26 1:37 ` [TUHS] " Jon Steinhart 2023-09-26 1:39 ` Jon Steinhart @ 2023-09-26 1:50 ` Andrew Hume 2023-09-26 2:13 ` steve jenkin 2023-09-26 11:28 ` Brad Spencer 2023-09-26 2:20 ` Kevin Bowling 3 siblings, 2 replies; 14+ messages in thread From: Andrew Hume @ 2023-09-26 1:50 UTC (permalink / raw) To: segaloco; +Cc: The Eunuchs Hysterical Society i’m sure there are standing references to all this. but as i recall, the 5ESS was a more or less local switching system. the guts of the long distance network were embedded in the (roughly) 140 1ESS’s. they ran a completely separate (and substantially older) code that supported things like SS7 (signaling code that was NOT embedded in the voice channel). the 1ESS was a complex piece of equipment. my interaction with this was tangential. throughout the 1980-90s, i had a tight grip on how accounting messages were handled within AT&T and wrote some C code that handled a a transition from one level of the standard software to another level. and that code ran inside the 1ESS. but this was a long time ago. > On Sep 25, 2023, at 6:24 PM, segaloco via TUHS <tuhs@tuhs.org> wrote: > > Hello, my studies lately bring me to the question: Are there any extant examples of telephone switching software, built on UNIX, from the various parts of the Bell System prior to the introduction of the 5ESS and 3B20D? My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in active use, that sleeping dragon can lie. > > What's gotten me curious is reading about 1ESS in a BSTJ volume I picked up, noting the particulars on how previous concerns of manual and electro-mechanical systems were abstracted into software. Even without surviving examples, were previous systems such as the 1ESS central control ever ported to or considered for porting to UNIX, or was the hardware interface to the telco lines too specific to consider a future swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS (switching, not source code) also comes to mind, although all I know that survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > By the way, it's funny, I have UNIX to thank for my current experiments with telephones and other signalling stuff, what with making me study the Bell System more generally. It's starting to come full circle in that I want to take a crack at reading dialing, at least pulse, into some sort of software abstraction on a SBC that can, among other things, provide a switching service on top of a UNIX-like kernel. I don't know what I'd do with such a thing other than assign work conference call rooms their own phone numbers to dial with a telephone on a serial line...but if I can even get that far I'd call it a success. One less dependency on the mobile... > > - Matt G. ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:50 ` Andrew Hume @ 2023-09-26 2:13 ` steve jenkin 2023-09-26 11:28 ` Brad Spencer 1 sibling, 0 replies; 14+ messages in thread From: steve jenkin @ 2023-09-26 2:13 UTC (permalink / raw) To: TUHS For those playing along at home, “Gecko” was written up. Virtual Data Warehousing, Data Publishing and Call Detail <https://link.springer.com/chapter/10.1007/10721056_8> and a conference paper of the same name <https://www.researchgate.net/publication/221629788_Virtual_Data_Warehousing_Data_Publishing_and_Call_Detail> from Databases in Telecommunications: International Workshop, Co-located with VLDB-99, Edinburgh, Scotland, UK, September 6th, 1999. Proceedings <https://www.researchgate.net/publication/321558305_Databases_in_Telecommunications_International_Workshop_Co-located_with_VLDB-99_Edinburgh_Scotland_UK_September_6th_1999_Proceedings> > On 26 Sep 2023, at 11:50, Andrew Hume <andrew@humeweb.com> wrote: > > i’m sure there are standing references to all this. but as i recall, > the 5ESS was a more or less local switching system. > > the guts of the long distance network were embedded in the (roughly) 140 1ESS’s. they ran > a completely separate (and substantially older) code that supported things like SS7 (signaling code > that was NOT embedded in the voice channel). the 1ESS was a complex piece of equipment. > > my interaction with this was tangential. throughout the 1980-90s, i had a tight grip on how > accounting messages were handled within AT&T and wrote some C code that handled a > a transition from one level of the standard software to another level. and that code ran inside > the 1ESS. > > but this was a long time ago. -- Steve Jenkin, IT Systems and Design 0412 786 915 (+61 412 786 915) PO Box 38, Kippax ACT 2615, AUSTRALIA mailto:sjenkin@canb.auug.org.au http://members.tip.net.au/~sjenkin ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:50 ` Andrew Hume 2023-09-26 2:13 ` steve jenkin @ 2023-09-26 11:28 ` Brad Spencer 1 sibling, 0 replies; 14+ messages in thread From: Brad Spencer @ 2023-09-26 11:28 UTC (permalink / raw) To: Andrew Hume; +Cc: segaloco, tuhs Andrew Hume <andrew@humeweb.com> writes: > i’m sure there are standing references to all this. but as i recall, > the 5ESS was a more or less local switching system. > > the guts of the long distance network were embedded in the (roughly) 140 1ESS’s. they ran > a completely separate (and substantially older) code that supported things like SS7 (signaling code > that was NOT embedded in the voice channel). the 1ESS was a complex piece of equipment. > > my interaction with this was tangential. throughout the 1980-90s, i had a tight grip on how > accounting messages were handled within AT&T and wrote some C code that handled a > a transition from one level of the standard software to another level. and that code ran inside > the 1ESS. > > but this was a long time ago. > >> On Sep 25, 2023, at 6:24 PM, segaloco via TUHS <tuhs@tuhs.org> wrote: >> >> Hello, my studies lately bring me to the question: Are there any extant examples of telephone switching software, built on UNIX, from the various parts of the Bell System prior to the introduction of the 5ESS and 3B20D? My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in active use, that sleeping dragon can lie. >> >> What's gotten me curious is reading about 1ESS in a BSTJ volume I picked up, noting the particulars on how previous concerns of manual and electro-mechanical systems were abstracted into software. Even without surviving examples, were previous systems such as the 1ESS central control ever ported to or considered for porting to UNIX, or was the hardware interface to the telco lines too specific to consider a future swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS (switching, not source code) also comes to mind, although all I know that survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. >> >> By the way, it's funny, I have UNIX to thank for my current experiments with telephones and other signalling stuff, what with making me study the Bell System more generally. It's starting to come full circle in that I want to take a crack at reading dialing, at least pulse, into some sort of software abstraction on a SBC that can, among other things, provide a switching service on top of a UNIX-like kernel. I don't know what I'd do with such a thing other than assign work conference call rooms their own phone numbers to dial with a telephone on a serial line...but if I can even get that far I'd call it a success. One less dependency on the mobile... >> >> - Matt G. So... I am speaking from a single point of view about stuff I worked on a very long time ago.... On the operations support system I worked on at AT&T/Lucent... we supported all manor of switches, all of those made by AT&T/Lucent and a whole lot made by other companies. This is what I recall... I believe that the 1A had left the building and no longer existed in any installed base in the US when I started, although we supported it still in our software because of the pain of ripping it out. The 1E did exist in some numbers (I may have these backwards, BTW... it might have been the 1A that existed and the 1E had crossed the rainbow bridge). I do recall that either the 1A or 1E had a lot of features, but it may have been more of a case of it just being around a long time and was infected with warts. The work horses, however, were the 4ESS and the 5ESS. The 4E did the long haul work and was often configured in a tandem set up (that was the term used, Tandem, which meant something specific at the time). The 4E was also a very large monster of a device... taking up pretty much an entire floor of a building. The software in it was very old with lots of add on sub-devices to provide new ability (our product used some of those sub-devices). Those sub-devices might have run their own operating systems and could have been computers all by themselves... that is, there were multiple glued together computers to get the 4E effect. The 5E was a lot cleaner and much smaller. It also had some sub-device stuff going on but nothing like what the 4E had. I do seem to recall that the 5E runs some version of Unix, at least on part of the device, but I don't remember if the main switching engine did, however (I suspect not, BTW). I am almost 100% sure that the 4E did not run Unix on the main switching engine, but it would not surprise me that it found its way into it somewhere or other (probably in multiple places given how large the device was). The 5E and 4E may have started out life with particular roles, but this wasn't very strict. That is it was completely ok for a 5E to do long haul work if so configured and it was very possible for a 4E to terminate a call. There was a great deal of flexibility present. AT&T long wire was a bit of a different place with respect to the 4E.. I seem to remember that at the time I was there they had something like 800 4E configured to do long distance service in the US. At least the traffic management part was managed by a set of Amdauls (using Unix as the operating system I believe) running an operation system product that was very much related to the one I worked on... simular internals for example and in my early days we all sat in the same group. The product I worked on also supported the SS7 switches (I say "switches" here, but that probably isn't exactly what they were. I also don't remember their actual names... STM, maybe??). I worked with the SS7 development group on a new operations system interface and during that conversation they mentioned that the SS7 switch ran a more or less unmodified Unix Solaris (one would assume on a Sparc). They also mentioned that they had performed kernel modifications in the past, but the cost of maintaining that sort of thing was very high, so they had moved away from doing that towards a more "push it to userland" way of thinking. -- Brad Spencer - brad@anduin.eldar.org - KC8VKS - http://anduin.eldar.org ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 1:24 [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? segaloco via TUHS ` (2 preceding siblings ...) 2023-09-26 1:50 ` Andrew Hume @ 2023-09-26 2:20 ` Kevin Bowling 2023-09-26 16:07 ` Sebastien F4GRX 3 siblings, 1 reply; 14+ messages in thread From: Kevin Bowling @ 2023-09-26 2:20 UTC (permalink / raw) To: segaloco; +Cc: The Eunuchs Hysterical Society [-- Attachment #1: Type: text/plain, Size: 2150 bytes --] On Mon, Sep 25, 2023 at 6:25 PM segaloco via TUHS <tuhs@tuhs.org> wrote: > Hello, my studies lately bring me to the question: Are there any extant > examples of telephone switching software, built on UNIX, from the various > parts of the Bell System prior to the introduction of the 5ESS and 3B20D? > My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in > active use, that sleeping dragon can lie. > Your best bet may be to contact Sarah Autumn at the Connections Museum, they have a 1ESS and 3ESS. http://www.telcomhistory.org/connections-museum-seattle-exhibits/electronic-switching/ I don't remember if they have the 1A variant but they should have the BSPs for all of this which would give you a lot of what you are after. > What's gotten me curious is reading about 1ESS in a BSTJ volume I picked > up, noting the particulars on how previous concerns of manual and > electro-mechanical systems were abstracted into software. Even without > surviving examples, were previous systems such as the 1ESS central control > ever ported to or considered for porting to UNIX, or was the hardware > interface to the telco lines too specific to consider a future swap-out > with, say, a PDP11 running arbitrary software? Columbus's SCCS (switching, > not source code) also comes to mind, although all I know that survives of > that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > By the way, it's funny, I have UNIX to thank for my current experiments > with telephones and other signalling stuff, what with making me study the > Bell System more generally. It's starting to come full circle in that I > want to take a crack at reading dialing, at least pulse, into some sort of > software abstraction on a SBC that can, among other things, provide a > switching service on top of a UNIX-like kernel. I don't know what I'd do > with such a thing other than assign work conference call rooms their own > phone numbers to dial with a telephone on a serial line...but if I can even > get that far I'd call it a success. One less dependency on the mobile... > > - Matt G. > [-- Attachment #2: Type: text/html, Size: 2804 bytes --] ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 2:20 ` Kevin Bowling @ 2023-09-26 16:07 ` Sebastien F4GRX 2023-09-26 18:45 ` segaloco via TUHS 0 siblings, 1 reply; 14+ messages in thread From: Sebastien F4GRX @ 2023-09-26 16:07 UTC (permalink / raw) To: Kevin Bowling, segaloco; +Cc: The Eunuchs Hysterical Society [-- Attachment #1: Type: text/plain, Size: 2619 bytes --] Hello, You beat me to it! I was about to reply that the Connections Museum of Seattle would have more info about this, or know people who do. This video of their channel shows a 3ESS software boot : https://www.youtube.com/watch?v=k865-VjWUk8 Sebastien Le 26/09/2023 à 04:20, Kevin Bowling a écrit : > > > On Mon, Sep 25, 2023 at 6:25 PM segaloco via TUHS <tuhs@tuhs.org> wrote: > > Hello, my studies lately bring me to the question: Are there any > extant examples of telephone switching software, built on UNIX, > from the various parts of the Bell System prior to the > introduction of the 5ESS and 3B20D? My focus veers earlier as > some 5ESS/3B20D/DMERT technology is still in active use, that > sleeping dragon can lie. > > > Your best bet may be to contact Sarah Autumn at the Connections > Museum, they have a 1ESS and 3ESS. > http://www.telcomhistory.org/connections-museum-seattle-exhibits/electronic-switching/ > > I don't remember if they have the 1A variant but they should have the > BSPs for all of this which would give you a lot of what you are after. > > What's gotten me curious is reading about 1ESS in a BSTJ volume I > picked up, noting the particulars on how previous concerns of > manual and electro-mechanical systems were abstracted into > software. Even without surviving examples, were previous systems > such as the 1ESS central control ever ported to or considered for > porting to UNIX, or was the hardware interface to the telco lines > too specific to consider a future swap-out with, say, a PDP11 > running arbitrary software? Columbus's SCCS (switching, not > source code) also comes to mind, although all I know that survives > of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. > > By the way, it's funny, I have UNIX to thank for my current > experiments with telephones and other signalling stuff, what with > making me study the Bell System more generally. It's starting to > come full circle in that I want to take a crack at reading > dialing, at least pulse, into some sort of software abstraction on > a SBC that can, among other things, provide a switching service on > top of a UNIX-like kernel. I don't know what I'd do with such a > thing other than assign work conference call rooms their own phone > numbers to dial with a telephone on a serial line...but if I can > even get that far I'd call it a success. One less dependency on > the mobile... > > - Matt G. > [-- Attachment #2: Type: text/html, Size: 4783 bytes --] ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 16:07 ` Sebastien F4GRX @ 2023-09-26 18:45 ` segaloco via TUHS 2023-09-26 23:32 ` George Michaelson 2023-09-27 6:15 ` Lars Brinkhoff 0 siblings, 2 replies; 14+ messages in thread From: segaloco via TUHS @ 2023-09-26 18:45 UTC (permalink / raw) To: Sebastien F4GRX; +Cc: The Eunuchs Hysterical Society [-- Attachment #1: Type: text/plain, Size: 3046 bytes --] Thanks for all the great information everyone. It sounds like I need to start considering a little trip down to Seattle to check out a few of these different computing/technology history organizations. They're a quick train ride down the coast, and my dreams of pulling together some sort of computing/technology history collective up here have been fruitless thus far, maybe I just need to recognize it as a big city thing and get more comfortable with considering little trips for this kind of stuff. - Matt G. ------- Original Message ------- On Tuesday, September 26th, 2023 at 9:07 AM, Sebastien F4GRX <f4grx@f4grx.net> wrote: > Hello, > > You beat me to it! I was about to reply that the Connections Museum of Seattle would have more info about this, or know people who do. > > This video of their channel shows a 3ESS software boot : https://www.youtube.com/watch?v=k865-VjWUk8 > > Sebastien > > Le 26/09/2023 à 04:20, Kevin Bowling a écrit : > >> On Mon, Sep 25, 2023 at 6:25 PM segaloco via TUHS <tuhs@tuhs.org> wrote: >> >>> Hello, my studies lately bring me to the question: Are there any extant examples of telephone switching software, built on UNIX, from the various parts of the Bell System prior to the introduction of the 5ESS and 3B20D? My focus veers earlier as some 5ESS/3B20D/DMERT technology is still in active use, that sleeping dragon can lie. >> >> Your best bet may be to contact Sarah Autumn at the Connections Museum, they have a 1ESS and 3ESS. >> http://www.telcomhistory.org/connections-museum-seattle-exhibits/electronic-switching/ >> >> I don't remember if they have the 1A variant but they should have the BSPs for all of this which would give you a lot of what you are after. >> >>> What's gotten me curious is reading about 1ESS in a BSTJ volume I picked up, noting the particulars on how previous concerns of manual and electro-mechanical systems were abstracted into software. Even without surviving examples, were previous systems such as the 1ESS central control ever ported to or considered for porting to UNIX, or was the hardware interface to the telco lines too specific to consider a future swap-out with, say, a PDP11 running arbitrary software? Columbus's SCCS (switching, not source code) also comes to mind, although all I know that survives of that is the CB-UNIX 2.3 manual descriptions of bits and pieces. >>> >>> By the way, it's funny, I have UNIX to thank for my current experiments with telephones and other signalling stuff, what with making me study the Bell System more generally. It's starting to come full circle in that I want to take a crack at reading dialing, at least pulse, into some sort of software abstraction on a SBC that can, among other things, provide a switching service on top of a UNIX-like kernel. I don't know what I'd do with such a thing other than assign work conference call rooms their own phone numbers to dial with a telephone on a serial line...but if I can even get that far I'd call it a success. One less dependency on the mobile... >>> >>> - Matt G. [-- Attachment #2: Type: text/html, Size: 5636 bytes --] ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 18:45 ` segaloco via TUHS @ 2023-09-26 23:32 ` George Michaelson 2023-09-27 6:15 ` Lars Brinkhoff 1 sibling, 0 replies; 14+ messages in thread From: George Michaelson @ 2023-09-26 23:32 UTC (permalink / raw) To: The Eunuchs Hysterical Society It may be obvious, certainly to anyone who owns the BSTL series (I don't. I read it in the library at uni), but would I be right in thinking the motivation behind "real time UNIX" was switching? It's the closest problem to Bell labs which demands time critical outcomes, the delay tolerance in circuit establishment and end-to-end telephony signaling was there, but it was finite. And, for capacity planning purposes being told a single unit of UNIX logic controlling a telephone switch could handle X call setup and tear-down events per second meant you could do the Erlang sums over customers call volumes and phone handset counts. The british digital switch experience in the System-X series Was GEC/Plessey, and ran CORAL which was the real time system they used to do MILSPEC stuff. It was explicitly fault tolerant design, lots of 2 and triple redundant componentry. -G ^ permalink raw reply [flat|nested] 14+ messages in thread
* [TUHS] Re: Known Specimens of Pre-5ESS UNIX Telephone Switching Software? 2023-09-26 18:45 ` segaloco via TUHS 2023-09-26 23:32 ` George Michaelson @ 2023-09-27 6:15 ` Lars Brinkhoff 1 sibling, 0 replies; 14+ messages in thread From: Lars Brinkhoff @ 2023-09-27 6:15 UTC (permalink / raw) To: segaloco via TUHS Maybe also visit the ICM Museum / SDF Museum. ^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2023-10-05 14:19 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-09-26 1:24 [TUHS] Known Specimens of Pre-5ESS UNIX Telephone Switching Software? segaloco via TUHS 2023-09-26 1:37 ` [TUHS] " Jon Steinhart 2023-09-27 2:46 ` Heinz Lycklama 2023-10-04 6:52 ` Kevin Bowling 2023-10-05 14:19 ` Kevin Bowling 2023-09-26 1:39 ` Jon Steinhart 2023-09-26 1:50 ` Andrew Hume 2023-09-26 2:13 ` steve jenkin 2023-09-26 11:28 ` Brad Spencer 2023-09-26 2:20 ` Kevin Bowling 2023-09-26 16:07 ` Sebastien F4GRX 2023-09-26 18:45 ` segaloco via TUHS 2023-09-26 23:32 ` George Michaelson 2023-09-27 6:15 ` Lars Brinkhoff
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