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This is an old revision of this page, as edited by 175.17.60.107 (talk) at 00:33, 13 November 2015 (→‎Sources?). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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Itanium

50-bits of physical memory addressing and 64-bits of virtual addressing

from itanium-9000-9100-datasheet.pdf and itanium-9300-9500-datasheet.pdf, useful or not. 119.51.184.193 (talk) 00:30, 15 February 2015 (UTC)[reply]

Perhaps useful on the Itanium page or the Montecito (processor) and Tukwila (processor) pages; not relevant to the very-definitely-non-IA-64/Itanium x86 instruction set so not useful on this page. Guy Harris (talk) 01:12, 15 February 2015 (UTC)[reply]
OK, this is another sock puppet of Janagewen, I am fighting for the fair and freedom of Wikipedia.org all the time for ever, OK, but is the information of that table relating with Itanium correct or not? 221.9.23.11 (talk) 01:18, 15 February 2015 (UTC)[reply]
It might depend on the chip and, in any case, unlike the Atom chips (which are standard x86 chips) and the Transmeta chips (which aren't supposed to run anything other than the Code Morphing Software and code that the CMS has translated natively; the operating system and application code that's run on it is IA-32 code). those Itanium chips that ran IA-32 code in hardware ran it as a compatibility mode, similar to PDP-11 compatibility mode on some VAXes, so the addressing limits for the IA-64/Itanium instruction set are completely irrelevant to its IA-32 engine, and don't belong here. Guy Harris (talk) 01:46, 15 February 2015 (UTC)[reply]
OK, I would wait till 15 April 2015 to blank the relate information on that table. — Preceding unsigned comment added by 221.9.23.11 (talk) 02:21, 15 February 2015 (UTC)[reply]

regarding protected mode

according to computer experts i talked to during the 90s protected mode was not available on the 80286. it was first available on the 80386. 84.213.45.196 (talk) 16:15, 9 July 2015 (UTC)[reply]

You presumably mean "experts", in quotes, as no actual expert, i.e. no actual knowledgable person, would say that. The 80286 most definitely did have protected mode - the reference for that on the protected mode page is:
  • "2.1.2 The Intel 286 Processor (1982)". Intel 64 and IA-32 Architectures Software Developer's Manual. Denver, Colorado: Intel. May 2007. p. 34.
What the 80286 didn't have was support for demand paging; it didn't divide any address space into fixed-length pages, each of which can be present in memory or absent.
It may not have been used as much on the 286 by the main operating systems for x86 processors, but there were definitely operating systems for the 286 that did use it, such as various UNIX ports and OS/2. Guy Harris (talk) 17:44, 9 July 2015 (UTC)[reply]
i tried to run games requiring protected mode on a 80286 and they would not work because it did not have protected mode. it could however run any super vga requiring game that did not require protected mode.84.213.45.196 (talk) 20:49, 9 July 2015 (UTC)[reply]
No, they didn't work because the 286 didn't have the right type of protected mode for the software you were trying to run. As the protected mode article says in the section on the 286:
The initial protected mode, released with the 286, was not widely used.[1] It was used for example by Microsoft Xenix (around 1984),[2] by Coherent,[3] and by Minix.[4] Several shortcomings such as the inability to access the BIOS or DOS calls due to inability to switch back to real mode without resetting the processor prevented widespread usage.[5] Acceptance was additionally hampered by the fact that the 286 only allowed memory access in 16 bit segments via each of four segment registers, meaning only 4*216 bytes, equivalent to 256 kilobytes, could be accessed at a time.[1] Because changing a segment register in protected mode caused a 6-byte segment descriptor to be loaded into the CPU from memory, the segment register load instruction took many tens of processor cycles, making it much slower than on the 8086; therefore, the strategy of computing segment addresses on-the-fly in order to access data structures larger than 128 kilobytes (the combined size of the two data segments) became impractical, even for those few programmers who had mastered it on the 8086/8088.

References

  1. ^ a b Kaplan, Yariv (1997). "Introduction to Protected-Mode" (Article). Internals.com. Retrieved 2007-07-24.
  2. ^ http://www.tenox.net/docs/microsoft_xenix_30_286_press_release.pdf
  3. ^ http://textfiles.com/internet/FAQ/coherent.faq
  4. ^ http://minix.net/minix/minix.html
  5. ^ Mueller, Scott (March 24, 2006). "P2 (286) Second-Generation Processors". Upgrading and Repairing PCs, 17th Edition (Book) (17 ed.). Que. ISBN 0-7897-3404-4. Retrieved July 2007. {{cite book}}: Check date values in: |accessdate= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
and the section on the 386 indicates that the 80386 fixed several of those issues - it offered a larger flat address space and made it easier to return to real mode from protected mode.
So your games that "required protected mode" really required the IA-32 version of protected mode, not just protected mode. Guy Harris (talk) 21:14, 9 July 2015 (UTC)[reply]
this. the inability of the 286 to switch from protected mode into to real mode (because that would have violated protection) made the use of 286 protected mode not backward compatible with x86 DOS. at that time, "IBM PCs" needed to be backward compatible to be successful in the market, so protected mode could only be used on the limited number of devices that didn't need DOS backward compatibility. — Preceding unsigned comment added by 96.246.59.19 (talk) 17:44, 11 October 2015 (UTC)[reply]
(Or on one of the limited number of IBM PCs that were running an operating system that didn't offer the ability to run arbitrary DOS applications, such as the various UNIX ports to the 286. But, again, "limited number", and you aren't going to be running DOS games there.) Guy Harris (talk) 19:16, 11 October 2015 (UTC)[reply]

Sources?

Originally I wrote -

These "generation" numbers appear to have no reliable source and seem to have been made up. This issue has been brought up at least twice in the past and I've never gotten an answer. If reliable sources are not forthcoming I'm going to delete the column. Jeh (talk) 20:19, 21 September 2015 (UTC)[reply]

However, this complaint applies to the entire table.

This table has collected a tremendous amount of "information" over the years and not a single item in it has a source.

If sources are not forthcoming, the whole thing has to go. Just having a serial sockpuppet and a longtime editor agree on changes is not enough.

Also, this table falls into the "parts list" category. A table of model names and features is not encyclopedic. If you want to see how information like this should be presented, take a look at the History of IBM magnetic disk drives article. It describes the significant changes in the progression of development of this technology, with information about why each change was significant and how it was used. Sadly, that article is also mostly unreferenced, but that's another matter. Jeh (talk) 20:29, 21 September 2015 (UTC)[reply]

Hello! Well, we all know that providing sources is absolutely necessary in all articles. The table provides a very good overview, there's no doubt about that, but it also needs sources. — Dsimic (talk | contribs) 02:22, 9 October 2015 (UTC)[reply]
This table could have already been made perfect, buy stopped by Jeh. Jeh might confuse the 46-bit virtual space, and it is ridiculously split into 14+32. What such an absurd expression, invented from Wikipedia! I doubt this Jeh have never got in touch with IBM OS/2 or Windows 3.x at all. He, possibly she, might also have few knowledge on x86 architecture at all. Enhanced version of PAE, 64-bit version of x86, and so forth are invented by this guy too. There was a failure project called PAE64 Linux, the developers thought the paging under long mode and compatibility mode is 64-bit version of PAE, but that project never lead to any practical use. There is another infamous project x32 API, which in other words, to prove x64 is completely another architecture rather than 64-bit version of x86 at all. The distinctions between x32 and IA-32 have already proven that x86-64 is just x86-64, none the biz with 64-bit version of x86 at all. Now the main page has already been protected from improving by real computer scientists from all over the world. Of course, I am not one of them. I am nothing, but I put effort to encourage all those real heroes to come into Wikipedia.org.
Best Regards,
Aaron Janagewen
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