Talk:Zilog Z800

Production
If the Z800 never entered production, then how could it have been used in "MSX Turbo R" computers?? Stan 17:43, 13 Nov 2003 (UTC)

IIRC they were the Hitachi versions, not the "real" Zilog ones. Things are somewhat confused by the fact that both the Z800 and Z8000 were to be released at the same time, MANY sources confuse the two.


 * Hitachi licensed the design then? I know nothing of this period in Zilog history, seems like a curious story. Stan 16:46, 15 Nov 2003 (UTC)


 * Hitachi second sourced the Z80 under licence. They have a history of second sourcing and then improving processors (see for example the 6309). At the time it was normal to have second sources to your products in order to get acceptance. In addition according to http://www.cpushack.com/2010/10/15/zilog-the-first-decade-z80-z8-and-the-z8000/#more-393 people could buy licences to produce and modify Z80 variants - just like ARM today 81.96.49.166 (talk) 21:00, 16 February 2018 (UTC)

However Zilog essentially ignored the Z800 in favour of their 32-bit Z8000 there is definitely a mistake in this sentence: the Z8000 was/is a 16-bit processor, the 32-bit Zilog processor was/is the Z80000. Since I don't know if the 32-bit or the Z8000 is wrong here I did not change anything so far IOOI 01:10, 3 Dec 2003 (UTC)


 * Z8000 is 16bit I think the article means Z80000. The Z8000 is 16bit but not Z80 like 81.96.49.166 (talk) 21:00, 16 February 2018 (UTC)

z280?
Article sounds like Z800 was burried before beeing born. But Z280 article sais that Z800 architecture was re-launched when moved from NMOS to CMOS technology.

If that is true - IMHO Z280 should be mentioned in this areticle as a Z800 spin-off

Disambiguation
I came to this page assuming to find an article about the Z800 3D visor. What about transforming this page into a disambiguation page with the links to Z800 (processor) and Z800 (visor)? -- Devil Master 14:19, 11 Sep 2006 (MET)

Five years
How is it "more than five years had elapsed" between 1985 and 1986? --Pkunk (talk) 19:13, 26 February 2013 (UTC)


 * This seems unclear to me as well. Dave Olsen mentions 'I just got in a new Zilog catalog and found the technical specs for the Z800 chip.' in a document dated 8th Jan 85. I've not got all the catalogues to check but that would be a useful search. Catalogues before that (eg the 1983/1984 Zilog Component Databook) include most of the data you'd expect on the Z800 (instruction set etc). It's also i the 1983 'Microprocessor Applications Reference Book vol2' from Zilog. Tilmann Reh who did only of the first homebrew Z280 platforms also cites 1983 in TCJ #53 (http://oldcomputers.dyndns.org/public/pub/rechner/zilog/z280/Z280_(G)IDE_a_compilation_from_TCJ_pages.pdf)

Something call the Z800 was announced in concept by 1978. See New Scientist 18th May 1978 "Microprocessors don't always work" about the introducing of the classic shift register BIST (built in self test) which includes the lines 'Starting this summer the microprocessor world will take another huge step forward in complexity, with the arrival of devices such as Zilog's Z800 processor -- said to have the power of the larger Digital Equipment Corporation PDP-11/70 minicomputer"

There's a ton of background timeline info in Computer History Museum Oral History Ref X4022.2006(http://archive.computerhistory.org/resources/text/Oral_History/Zilog_Z8000/102658075.05.01.acc.pdf). Faggin talks about the Z800 as a concept and reserving the id for a 'super Z80' so naming the Z8000 as 8000 not 800 and also that the Z800 didn't happen until after he left which would put it 1981+. I think this adds to the confusion because there are discussions and advertising spin about Z800 that clearly are about what became the Z8000.

So I think the timeline is

1978 - Zilog have a Z800 at least enough to be spinning it to the press (but that's the Z8000 prior to Faggin changing the name) (They concentrate on the Z8000/80000) 1980 (end of) Faggin leaves Zilog some point after that they begin the Z800 (as Faggin says it happened after he left and he was CEO so he ought to know...) 1983 - It exists enough to be in a databook and promoted for some products. 1985 - They finally announce it as a product (by then in CMOS) 1986 - They ship it.

At which point the comment would make sense. All very sad because if Zilog had their ducks in order they'd have been in the IBM PC and we'd have had memory protection, virtual memory, cache and multi-processor support in the IBM PC from day one and been able to run real OS's back then.

That would also tie in with the descriptions elsewhere of why many of the bugs never got fixed because they'd have had to import the Z800 design into their current design tools. And also of course by 1986 it's up against not only a well established 80286 which also had memory protection since 1982, and the newfangled 80386 which is 32bit with paged MMU and buried it.

The computer history Z8000 article is well worth reading. It explains much about the state of things in Zilog and where Faggin says they were trying to do too many things and there were management problems.

81.96.49.166 (talk) 21:00, 16 February 2018 (UTC)

And another data point I just found Business Week July 26 1982 in 'A chip waiting to explode: Customers were confounded by the complexity of the 16bit microproccessor chip' says of Zilog 'Late next year, it plans to launch a high-performance, 8-bit microprocessor called the Z800. Industry experts suggest that next year could be too late, but Vonderschmitt argues that "an upgraded 8-bit product will benefit from all the software and all the peripheral circuits that already exist."'

So we have 1982-1986/7 - which sounds about right

81.96.49.166 (talk) 21:19, 16 February 2018 (UTC)

What is EDN?
The article refers to a mysterious "EDN November 27, 1986 p133" instance. Can anybody explain what is this EDN? Pkunk (talk) 18:56, 4 March 2013 (UTC)
 * A magazine. EDN stands for Electronic Design News.   174.25.9.105 (talk) 06:55, 28 October 2015 (UTC)