Talk:Unicos

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The title of this article is spelled UniCOS, but in the article the OS name is spelled UNICOS, all caps; I suggest this page be moved back to UNICOS (which is currently a redirect here). Qwertyus 17:42, 21 February 2006 (UTC)

That's a good idea; AFAIK, Cray Research always used the all-caps "UNICOS". Letdorf 20:11, 21 February 2006 (UTC)

I would agree with you on these minor points. UNIX was a troff macro which the Labs people inserted in their documentation to note Western Electric's and then later Bell Laboratories' trademark. It was in a slightly reduced pointed size and all caps. This is further complicated by UNIX's case sensitivity. I would suggest not making too much of this.

On different points: there seems to be memory loss in that I snipped "binary" out of compatibility. It wasn't in exceptional cases (some X-MP-> Y-MP, C-90 {some}, and T-90). Vastly different hardware can prove this: the changes are all to benefit performance. If you are not thinking performance, you are not thinking as the corporation and the man did. The compatibility argument was made and attempted by IBM and CDC (makes business sense to those with an installed base), but Cray's market (the high-end market) is there to solve high end problems.

Additionally, I cleared up and elaborated on Unix-like. Unicos got Ken Thompson's personal nod.

--enm 19:22, 26 April 2006.

I don't recall that any Cray-1 ever ran UNICOS. Cray-1s were at the end of their line; X-MPs were the machines to buy. Additionally, UNICOS had certain hardware requirements and so few Cray-1s were planning to simply do a software upgrade, it wasn't worth it change the software for those few sites. Some one should check with Fred if there were any 1Ses, much less 1Ms, to run UNICOS.

--enm 19:24, 26 April 2006.

UNICOS was definitely supported on Cray-1 systems. Remember that the Cray-1 and the early X-MP had the exact same instruction set (we could quibble about a minor nuance or two.) Cray-1 systems were required to have an I/O Subsystem in order to run UNICOS - which also meant a minimum of 2 mwords of memory. The Cray-1 was at a disadvantage compared to newer machines though, because UNICOS liked lots of central memory. And being a product of the 1970s, the Cray-1 didn't have a lot.

On binary compatibility: CRI designed the X-MP->Y-MP->C-90->T-90 series with 1 generation of backwards compatibility. That is, Cray-1 binaries could (almost always) run on X-MP systems. X-MP binaries (and perhaps Cray-1 binaries) could run on a Y-MP in 'X-MP compatibility' mode. Likewise the C-90 had a Y-MP compatibility mode, and the T-90 had a C-90 compatibility mode.

Wws 1 May 2006.

Well just as a note: which Cray-1 site ran Unicos? I now have the entire list from that era including the all the classified sites. 1s differed from Xs basically on the locking and multiprocessor related instructions. I am not certain I would call those minor as a former user of multitasking. Minor edits on GOS are OK to me: water under the bridge. C-90s were Y-MPs (w/o getting into the NDA). I have no hardware indication of modes, just differing instruction sets and feature registers. The architecture wasn't a VAX or an IBM System/370 with VM.

--enm 1 jun 2006