Current base All-In-One zip
You may prefer to get the official version at squeak.org, they maintain historical version archives going back decades.
My first professional Smalltalk use was in 1985/6 and thebefore the DGUI was in the mid nineties. SPO was/is a term for the system operator console in Burroughs/Unisys MCP. Similarly WFL is Work Flow Language, the MCP Job Control Language and a future intent for the domain space Master Control Program. DCP is domain control program which is novel to domain space.
The SPO would be associated with a particular Operator Display Terminal (ODT), by assignment in the NDL (Network Definition Language) sources for the machine controlled.
The TD series (classic TD830 shown) were typically used in the seventies and early eighties. The "dumb" terminal is actually in the keyboard. I also used an "SR" station type with a more programmable microprocessor introduced after the TD.
This image shows a lot of reverse video, they were normally white text on black. I believe they also could be configured like a contemporary IBM 3270 for "greenscreen" green on black or amber. There also was an ET series (shown below), a more modern version of the TD monitor (shown above, an 800 I believe).
DGUI Linux, Mac, or Windows desktop is reference version.
A web SPO is available here.
In my reimagined context, SPO is just the smalltalk code which is developed to run in Squeak 5.3 or later from desktop or web in support of domain space.
"DGUI" could be somewhat misleading, since here "domain" refers only to the GUI aspect of domain space as such. In fact. anything that could run on a node could produce a native or web UI. The Domains GUI prefers Smalltalk on aesthetic as well as practical grounds but redvant is also used and many embedded systems have their own.
"Supervisory Print Out"
In the original MCP based systems one or more consoles could function as the "SPO", the system operator interface. Originally it stood for "Supervisory Print Out" in the early MCP (presumably B5000 or possibly earlier). The ATTACHSPOQ DCALGOL function determines the current SPO.
In my homage it has become simply "SPO" ('spoh') for DCP/MCP, the set of squeak sources as described above as a UI for the dominion control program in the style of the Burroughs MCP. BTW, this is a good place to point out the diff between "Burroughs MCP", "Unisys MCP", and just "MCP". The second is the product marketed by Unisys which until recently I had not had hands on since my use of it as systems programmer in the 80s but which is now available as "MCP Express" that runs under Windows. The last is my invention which is no more than inspired by Burroughs MCP 4, the version of the Algol OS with which I had paid experience than 18/19 the current one in 2020/4718.