Talk:IBM System/360 Model 67

message: I am currently revising/creating a series of articles related to the early days of CP/CMS. This involves the various systems referenced by the family tree at the end of this article, plus entries on Cambridge Scientific Center, Lincoln Laboratory, Type-III product, etc. Kindly bear with me while I get the various pages in synch. (I was doing some of this work in a private sandbox, but thought it would be better to start putting out some text. I do intend to provide a good number of citations and references, plus do some systematic editing/wordsmithing, over the next few weeks. Obviously feel free to jump in and fix anything that needs attention. Trevor Hanson 22:04, 19 October 2006 (UTC)
thread_title: Plan

message: This article includes the following statement which I'm not sure is correct and which may be misleading:
 The S/360-67 design included a radical new component for 
 implementing virtual memory, referred to as the "Blaauw Box" 
 after its designer Gerry Blaauw. This device was originally 
 designed during the main S/360 project, but had been excluded 
 from the S/360 design; it was revived for IBM's failed proposal 
 to Project MAC, for a customized S/360, and finally came to 
 fruition in the S/360-67. 
The following quote is from the article "The IBM 360/67 and CP/CMS" by Tom Van Vleck that is available at http://www.multicians.org/thvv/360-67.html:
 CP-67 didn't use the segmentation features of the 360/67; 
 In fact, segmentation was not a feature of the original Blaauw 
 proposal, but was derived from a 1966 JACM paper by Arden, 
 Galler, O'Brien, and Westervelt of Michigan. Both TSS and 
 MTS did use segmentation, but not as pervasively as Multics 
 did on the GE 645. 
Tom Van Vleck's description agrees with the memories of two staff members (Mike Alexander and Scott Gerstenberger) who worked at the University of Michigan's academic Computing Center when the first 360/67 to be delivered outside of IBM arrived at Michigan in the fall of 1966. Van Vleck's description also agrees with Bruce Arden's unpublished memoirs. Bruce was an Associate Director at UM's Computing Center and was directly involved in the discussions with IBM about the model 65M (what became the model 67). He is also one of the authors of the JACM article that Van Vleck mentions.
I'd suggest rewording the current article to read:
 The S/360-67 design included a radical new component for 
 implementing virtual memory, the "DAT box" (Data Address 
 Translation box). DAT on the 360/67 was based on the 
 architecture outlined in a 1966 JACM paper by Arden, Galler, 
 Westervelt, and O'BrienB. W. Arden , B. A. Galler , T. C. O'Brien , F. H. Westervelt, Program and Addressing Structure in a Time-Sharing Environment, Journal of the ACM (JACM), v.13 n.1, p.1-16, Jan. 1966 and included both segment and page 
 tables. The Model 67's virtual memory support was very similar 
 to the virtual memory support that eventually became standard 
 on the entire S/370 line.
Jeff Ogden (talk) 06:18, 5 July 2010 (UTC)
thread_title:  DAT vs. the "Blaauw Box" 

message: This article is or should be primarily about the IBM S/360 Model 67 computer, but it also talks quite a bit about CP/67 and Virtualization. Unless there is an objection, I plan to rework the article to sharpen its focus on the 360/67 and to add links to other articles on CP/67 and Virtualization.  I will also try to address the issue of too few inline citations. Jeff Ogden (talk) 01:56, 15 July 2010 (UTC)
replies: text: The changes suggested above were made last week. Jeff Ogden (talk) 16:38, 5 August 2010 (UTC)
thread_title:  Rework to focus more on the 360/67 and less on issues covered in other articles 

message: Under “Features” I found this sentence: “A simplex configuration allowed from 2 to 4 processor storage units (512K to 1M bytes). A duplex configuration allowed from 3 to 8 processor storage units (768K to 2M bytes).”  While strictly speaking this is correct, it is misleading because there were three basic configurations available: simplex, half-duplex and duplex.  The half-duplex configuration could have as few as two IBM 2365 components.  If there is no objection I will add this. John Sauter (talk) 21:27, 10 August 2010 (UTC)
replies: text: No objection from me. I think this is a good change. Jeff Ogden (talk) 01:38, 11 August 2010 (UTC)
replies: text: I have reorganized the “Features” section into three parts: “Features”, “New Components” and “Basic Configurations”. John Sauter (talk) 13:54, 11 August 2010 (UTC)
thread_title:  Configurations 

message: The article says "The 200 ns cycle time put the S/360-67 in the middle of the S/360 line in terms of processor speed (3.9 times faster than the Model 30 at 750 ns and 3.7 times slower than the Model 195 at 54 ns)." As I recall, the model 30 implemented the 360 instruction set in microcode and was much slower than 1/3.9 times a model 65 or 67. One can not simply look at cycle times when comparing old machines.--agr (talk) 13:03, 6 January 2013 (UTC)
replies: text: Yes, every S/360 except the 44, 75, 91, 95 and 195 was simulated. The microinstructions on the smaller models were narrower, the internal registers were shorter and the data paths to memory were narrower, so cycle time was not the most important factor in system performance. There are some CE manuals on bitsavers, and I have some on dead trees, if you want some exact numbers for selected models. Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:49, 9 January 2013 (UTC)

text: I simplified the statement in the article, so that it now reads "The 200 ns cycle time put the S/360-67 in the middle of the S/360 line, between the Model 30 at the low end and the Model 195 at the high end". If someone can provide a more quantitative description of the performance of the Model 67, that would be a welcome addition. --Jeff Ogden (W163) (talk) 12:39, 28 January 2013 (UTC)
thread_title:  Bad speed comparison 

message: The introduction says this, but the IBM System/360 Model 65 had time-sharing.  Bubba73 You talkin' to me? 02:48, 2 August 2018 (UTC)
replies: text: As in Time Sharing Option? Guy Harris (talk) 06:10, 2 August 2018 (UTC)
replies: text:  I;m not really sure.  But the first time-sharing I did was in 1972 in a 360/65. And the article on the 360/65 mentions it.  Bubba73 You talkin' to me? 06:28, 2 August 2018 (UTC)
replies: text:  The M65 article definitely mentions TSO, so presumably that counts as at least one flavor of time-sharing for the 360/65. Guy Harris (talk) 07:01, 2 August 2018 (UTC)
replies: text: My experience is the same as Bubba73's. HiLo48 (talk) 07:03, 2 August 2018 (UTC)

text: Not just TSO, either. but, e.g., APL\360, CALL/360, Conversational Programming System (CPS),  Remote Access Computing System (RAX), Remote Users of Shared Hardware (RUSH). Shmuel (Seymour J.) Metz Username:Chatul (talk) 15:42, 2 August 2018 (UTC)
thread_title:  Only 360 to support time-sharing? 

message: The article has Category:VM (operating system), but VM was the major rewrite of CP-67 and could not run on a 360/67. Shouldn't there be a CP-67 category and Category:CP-67 instead? Shmuel (Seymour J.) Metz Username:Chatul (talk) 08:26, 22 June 2020 (UTC)
thread_title:  Category VM? 

message: I've added a table for the Extended PSW; Currently it's an infobox with a 55% font scale. Does it look OK as is, or should it be a wikitable and at a different location? 21:19, 3 January 2021 (UTC)
replies: text: I find the small text hard to read, but I don't have any good ideas for how to make it better.  John Sauter (talk) 21:31, 3 January 2021 (UTC)
replies: text: Make it bigger? :-)  Either put a short introductory paragraph explaining why there's an alternate form of the PSW (for 32-bit addressing and VM support) before it in the "Features" section, or move it to the "Virtual memory" section and do it there. Guy Harris (talk) 21:43, 3 January 2021 (UTC)

text: If you change the scale factor from 55% to, e.g., 88%, then I'd advise changing the class from infobox to wikitable, and possibly moving the table. I had considered putting it where the text mentions the extended PSW mode, but was afraid that that would break the flow of the text. Shmuel (Seymour J.) Metz Username:Chatul (talk) 01:58, 4 January 2021 (UTC)
thread_title:  Extended PSW mode