Great point. Does a VT100 have a pass-through serial port? Maybe the development machine was connected to a pass through serial port on a terminal and then sent command to the DEC-20 to send the files. So there would have been some sort of connection from the DEC-20 to IBM. Leased line? Packet switched?
A great puzzle. http://www.classiccmp.org/cini Long Island S100 User’s Group Get Outlook<https://aka.ms/qtex0l> for iOS ________________________________ From: cctalk <cctalk-boun...@classiccmp.org> on behalf of Dennis Boone via cctalk <cctalk@classiccmp.org> Sent: Sunday, September 27, 2020 10:03:23 PM To: cctalk@classiccmp.org <cctalk@classiccmp.org> Subject: Re: SCP/Microsoft 20HAL uploader > Excellent! That's a great piece of info. Not sure why a TOPS-10 > command would be embedded in a program like this. The notion of > filtering/delay itself makes sense but that command would make sense > only if IBM had a DECSYSYEM too, no? That part's a puzzler. Perhaps the link was from the PC to the MS DEC-10 and thence out to IBM? De