The Old Joel on Software Forum: Part 4 (of 5)

Why did Zilog fail?

Why did Zilog fail?

Back in the times of Intel 8080, the Zilog Z80 microprocessor was a lot better than 8080.

So.. why did Zilog fail?

Maxus
Thursday, April 29, 2004

Fail? Zilog was exhibiting at an embedded systems conference I attended not too long ago and their web site is still there.

There processors were not selected by IBM to become part of the PC, but that is also true of the Motorola 68000 and the National 32000. I sometimes wonder why the 32000 has almost disappeared. It seemed to be a rather nice CISC processor at the time. Perhaps it was too expensive. And National never seemed to make any real effort to sell it.

mackinac
Thursday, April 29, 2004

They didn't disappear: http://www.zilog.com : "ZiLOG - Providers of 8-bit Flash Microcontroller Solutions".

Wikipedia history:

http://64.233.161.104/search?q=cache:9tK5LF4-LnAJ:en.wikipedia.org/wiki/Zilog_Z80+zilog+history&hl=en&lr=lang_en

My perception is exactly what the Wikipedia entry says: Zilog never developed marketable 16 and 32 bit processors in a timely manner. They were everywhere in the days of Osborne and Kaypro luggables and they were the "real" alternative to IBM PC architecture boxes in the early 80s. In fact, I recall some Z80 systems having specs comparable to the IBM-PC.

Z80s kind of vanished from consumer PC by the mid 80s, although I used to get calls from headhunters occasionally for places like Tokheim in Ft Wayne, IN that made gas pumps that used the Z80 as a controller.

Their 16 bit CPU ( at http://en.wikipedia.org/wiki/Zilog_Z800 ) was introduced in 1985. The 80286 came out in, what, 1983?

Or, http://en.wikipedia.org/wiki/Zilog_Z8000 : "The Z8000 was a 16-bit microprocessor introduced by ZiLOG in 1979. Not Z80 compatible! Although it saw steady use well into the 1990s, it was never very popular." Lack of downward compatibility sounds like a killer.

Bored Bystander
Thursday, April 29, 2004

The 320xx series died because of really bad reliability issues -- http://en.wikipedia.org/wiki/NS32016

I mean, the big reason why Intel won was not because they got things right (the i860, i432, and Itanic all bear witness here) but because they managed to luck out in the beginning and ended up being what the PC was built around and haven't made any sold-the-company-into-bankruptcy mistakes lately.

Flamebait Sr.
Thursday, April 29, 2004

Broadly speaking. Z8000 based unix boxes stank, and if I remember rightly you couldn't autoport Z80 code running on CPM. So in the high end market they lost out to Motorola mostly because it had a 64K segmented architecture vs the 68K 32 bit architecture, at the low end Intel with the 8086+MSDOS meant you could machine port your 8080 code and get decentish performance.
Otherwise parts like the Z8530 weren't bad designs, although it's a complete bitch to program as the setup registers have to be done in the right order. Zilog are still going strong in the embedded space.
Motorola had other problems with early versions of the 68K mostly to with restarting instructions after a memory management trap. I think some early designs for the 68K ran two out of step so the instructions could be restarted after a memory exception.

Peter Ibbotson
Thursday, April 29, 2004

I worked at Zilog ten years ago. What happened is really simple - chip design was their specialty. All the chip design people left or were let go for various (mainly 'cost related') reasons. In the end, there was not even a single person left who knew how to run the layout annealing algorithms.

It's an old story and one that is being replayed in much of the industry today - the illusion that designers are not needed to develop the new products that will make a product.

Currently, Zilog only licenses designs from others. They do no development themselves. And thus, they are irrelevant and already dead despite the lingering momentum.

former Z-man
Thursday, April 29, 2004

My recollection is that the Z8000 Lead Designer was a guy they hired from Intel. About 3/4 of the way through the design, it became clear that the design was in trouble. He returned to his old job at Intel.

Draw your own conclusions.

Tom H
Thursday, April 29, 2004

Nope. Zilog shrunk (they were once owned by Exxon!) because they went from 1 8 bit Z80 hugely successful processor to a pure 16 bit processor (Z8000?).

They broke backward compatibility with the Z80 at a time when intel was smart to come out with 8088 which was a combo 8/16 processor cheaper to design for and which would use many existing off the shelf chips including memory due to its 8 bit wide bus. They never recovered their momentum after that. But they sure as heck sold a lot of Z80 based computers like the Timex Sinclair Spectrum

Same with the folks who made the 6502 which was used in the earlier Apple

Code Monkey
Thursday, April 29, 2004