Talk:SDS Sigma series

Instruction format
I suspect the instruction format was the same for all 32-bit Sigmas, but hesitated to say so without checking the manuals. — Preceding unsigned comment added by Peter Flass (talk • contribs) 06:46, 22 January 2012 (UTC)‎


 * OK, I checked the Sigma 5/6/7/8/9 manuals at bitsavers.org. The general format just has a 17-bit address field; the different interpretation depending on the high-order bit of that field is specific to the Sigma 9 in if "real extended addressing", which is a mode that allows non-virtual access to more than 128K words of physical memory, is in effect.


 * The manuals also describe a different format for immediate instructions, so I left this as just describing memory-reference instructions. Guy Harris (talk) 02:24, 23 January 2012 (UTC)

Competition
"At the time the only competition for the Sigma 7 was the IBM 360."

What does this mean? In which space did the Sgma 7 and IMB 360 compete? It seems to me the PDP-6 was also a competitor. Lars Brinkhoff —Preceding undated comment added 06:33, 1 February 2017 (UTC)


 * Since only 23 PDP-6s were sold, it doesn't seem that they were much of a competitor. But the PDP-6 led to the PDP-10, which could have been a competitor. Gah4 (talk) 07:47, 1 February 2017 (UTC)

“First e-mail on Arpanet”
You might like to add the episoade on http://www.historyofinformation.com/detail.php?entryid=1108. Nice crash! And it wasn’t really e-mail, but some take it as such. – Fritz Jörn (talk) 09:00, 15 October 2019 (UTC)


 * Or maybe just copy from the last paragraph of ARPANET, which is where that site got the story, and which has a reference for the story. Guy Harris (talk) 18:38, 15 October 2019 (UTC)