8086 powered IBM PC compatible

I don't recall ever seeing an 8086 compatible. I remember keeping an eye out, too. I vaguely recall there wasn't any

Could you point me to anything that might refresh my memory of an 8086 or 80186 based IBM PC compatible (not just MS-DOS) that could actually run most IBM PC software without modification? (I seem to recall some kind of OEM MS-DOS did. Just not all IBM PC software.)

Jon

I don't need the machines right now. And I don't see any boards that expand out the old ISA connectors, 8 or 16 bit. (I think I knew about them before, but it's nice to get reminded.) I do see the PC-Co, which requires an ISA slot. Might be something with through-holes, but no connector, that I missed. The search box doesn't come up with anything but the PC-Co, though.

Interesting thing is that I do have the Paradigm tools (and a few documents and software from other companies that support DOS development, such as SSI embedded linker/locators and Microsoft 16-bit compilers.)

But less call for that work, these days. I still dabble, since I design and build ISA boards, still.

By the way, I got a complete Paradigm development kit for free with a free license for as many machines as I'd like to set up for the rest of my life, direct from the owner, some years ago. My understanding is that the product I received can be given away, though I'd have to go back and check my emails first. It's the summer 2002 version, memory serving. Which is quite adequate for embedded and operating system work. (Paradigm development tools are based on the Borland c compiler, but forked and modified, as I recall.)

Jon

DR-DOS would. Epson used the NEC V20 & V30 CPUs in their first PC compatible machines which were the subject of an Intel vs NEC patent infringement for reverse engineering of microcode. NEC might also have used them - I never had the chance to dismantle an original NEC9801.

The V30 was an 8086 compatible chip was exactly pin compatible with the Intel but about 20% faster (more on some ops). It could also emulate an

I had an Epsom machine at home with a V30 CPU & Hercules graphics. The V30 was a heck of a lot faster at bit twiddling than the 8086.

Cyrix did the first 80x87 pin compatible FP chip and their scrupulous black box analysis of the IEEE floating point specification found several inconsistencies (ie bugs) in the Intel implementation of it.

The dying embers of Ollivetti M20 Zilog Z8000 machines were still lingering around at about the same time. Our secretary had one.

Regards, Martin Brown

The first Compaq Deskpro used an 8086 running at 7.14 MHz, but was capable of running add-in cards designed for the 4.77 MHz IBM PC XT.

The IBM PS/2 models 25 and 30 were built with an 8 MHz 8086.

The Tandy 1000 SL-series machines used 8086 CPUs.

And COCOM rules were set by lobbyists so that it was a serious criminal offence to export BBC micros or Compaq PC compatibles to Russia whilst IBM XTs were OK. It was particularly bad when in the same week an IBM salesman got an industry award for selling 2000 IBM XTs (with hard disks) to Moscow University and a West German businessman was jailed for 5 years for selling 300 tape based BBC micros to East Berlin.

Ollivetti M24 was a full 8086 IBM PC compatible also sold as AT&T 6300.

It was highly compatible with the IBM design. The earlier M20 (Z8000 based) was not although they produced a daughter board for it.

Many 8086 machines in that early era were of limited PC compatibility. Almost everything had better graphics than the rubbish IBM offering.

Regards, Martin Brown

ALl "XT" class, and compatibles, were 8086 based. The '186 was rarely used for a PC type system because of interrupt (and I/O) conflicts. Using it automatically made it non-comparable. Some did it anyway but anything written "to the metal" had problems.

All "XT" compatibles used the '86. The '86 was the reason for going to the

ld need

A very interesting history of PC processors.

I owned a PC/XT. It used an 8088. It also didn't have the

I certainly remember these things.

Jon

need

=20

Of course that task was made massively easier by plenty of IO = instructions that operated on bytes (8 bits) instead of words (16 bits). Even the DMA chip could operate on bytes.

On Thu, 06 Oct 2011 23:42:14 -0700 in sci.electronics.design, Jon Kirwan wrote,

I could be vaguely misrecalling, but wasn't the PC JR a 186?

No, it was an 8088, too.

You're right, the difference between the PC and /XT was the memory (64Kx1-256/640KB max vs. 16Kx1-64KB max).

There were 8086 fully compatible PC/XT class systems made, however.

And an MFM hard drive. Can't recall exactly, but I think it was 10Mb. Slow. But better than the PC's floppies or the PC's cassette tape drive interface, which I also remember because I used a Radio Shack cassette recorder to save programs.

Yes, I'm getting that message loud and clear. I distinctly remember 'difficulties' there and a general conclusion "not to bother with them." But some did, apparently, and fewer still actually managed to create something PC compatible from what I've recently read posted here. Supplements and corrects my recollections.

Jon

written

Sure. I was talking about the MB.

The '286 came out just a couple of years later, about the time the whole thing took off. After the '286, there was no reason to use the '86 at all. The '186 was still cost-effective, but it wasn't 100% compatible, without which a system wasn't sellable.

To be PC compatible, all 8 and 16 bit instructions have to operate correctly regardless. That 8/16 bit issue gets more complicated with PC/AT, and then with 386 and later. Bus interface unit would be hard to make from discrete logic parts.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

David Harmon wrote in news:W6mdnXNtWeX3IAzTnZ2dnUVZ snipped-for-privacy@earthlink.com:

We bought 3 186 IBM pc's at the time, but about 6 months later they switched to 286 cpu's. We used IBM network cards in them, those worked without failure for about 8 years, until replaced by ethernet.(3com). Never noticed much difference between them, but they all had math co-processors. So yes, for a brief time they were on the market.

No you didn't. IBM never used the 186 or 188 in PCs (couldn't have). AFAIK, the only thing they used the 8086 in was the System/23 DataMaster (a.k.a. DataToaster).

Olivetti M20 / M24??? were 8086 based. It was really fast, better than early 286s. XTs were 8088 based and slooooow.

We had a lot of the Olivettis running QNX. Was a good thing.

I also got a datasheet for an 80187 under NDA, but that chip never saw the light of day. Instead they proposed a hack with a 8087 and a PAL IIRC.

At that time I have built a lot of 80186 machines for Multibus I and AMS/SMP bus, also with _very_ early 186 silicon.

Gerhard

p.s. I suppose, Intel gave on the iAPX[1234]86 type numbers, because now they would have to pay royalties to Apple.

" snipped-for-privacy@att.bizzzzzzzzzzzz" wrote in news: snipped-for-privacy@4ax.com:

Curious. You know better, what we bought??????? I have had years in which to read the label on the front of the case, showing 186. That was in the Netherlands, and I dont think the label was lying.