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8087 on 8088 motherboard that have no socket for it

I don't see any reason to swap 8088 and V20 anymore. V20 is compatible enough to run any 8088 software. And with new PC-Zip driver an important reason to install a V20 has gone, saves a lot of money if one has many 8088 or 8086 based PCs, now ZIP drives run reliable with the Intel processor. The speed increase between the intel and NEC isn't that big and if I need a faster DOS machine I just use another out of the Ivrea factory in my collection...
 
ZIP drives are the most intuitive and comfortable way to transmit data between modern computer and MS-DOS PC. It works out of the box without modifying the old PC. The only requirement is a parallel port. Think also about laptops and so of this era. Think about very compact PC which may not have ISA slot, or need external expansion box which is hard to get, like Commodore PC 1, Atari PC 1, Olivetti M19 (has internally only low profile ISA) and Olivetti Prodest PC 1, Sinclair PC 200, and yes also Euro PC. They all have very limited expansion capabiliies.
 
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1ST1 said:
ZIP drives are the most intuitive and comfortable way to transmit data between modern computer and MS-DOS PC.
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If you say so...
1ST1 said:
... and yes also Euro PC. They all have very limited expansion capabiliies.
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Well, that's your problem, not mine - mine has an external industrial ISA backplane extender - Adlib, MPU401, VGACard, 1 MB RAM, and yes, XT-CF-Lite. Euro PC. I believe that file transfer with a modern computer is a bit more intuitive with a CF card than with a Zip drive (heck, does a "modern computer" have a parallel port? oh, that's right - it doesn't). With an external industrial ISA backplane, there are no limits on extensibility whatsoever.

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Yes, one can do so, for example also with the M19 and Prodest PC 1, but then it is not anymore so compact, it gets sensible and untransportable.
 
1ST1 said:
Yes, one can do so, for example also with the M19 and Prodest PC 1, but then it is not anymore so compact, it gets sensible and untransportable.
Click to expand...
It's not that bad... I can just pull the ISA connector plug on the left, and then it's pretty easy to transport as well. It's not worse than transporting a ZIP drive ;)

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So, I installed my CoProcessor - it works, but the Intel Test Program reported an "Environment Error" and that it isn't installed correctly. Also, I couldn't observe a proper speedup yet. I have not wired up the NPINT to the Faraday chip. Maybe that's the problem?

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Oh! I had the wrong test program! The second MCPDIAG program from this thread seems to think that my 8087 is installed correctly!
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I was now able to measure the difference / speed up, and it's indeed a factor of ~8 to 10 for my graphics program.


(Sorry, German only, but you can see the speed difference for the test program with and without 8087).

Is there a way to disable the 8087 in software? One issue is that I needed to pull the 8087 for TurboC to actually *not use it*. I was thinking that if you select "Emulation" for the Compiler Code Generation setting, that it would *always* emulate FP, even with 8087 installed, but that's not the case: "Emulation" setting means that if it's present, then it uses the 8087, *else* it will use software emulation. Than there is "None", which is no FP at all (doesn't work here), and 8087, which will *only* run if the 8087 is installed. I'd like to be able to compile a program that will *not use the 8087 at all*, but that doesn't seem to be possible with TurboC.

Maybe there is a software switch to "disable" the 8087 until next boot?
 
Supposedly the "Environment Error" shows up if you don't add the command SET 87=YES to your AUTOEXEC.BAT file. However, I did so on my Tandy, and the Intel test utility still gives me that error.
 
... @1ST1 since you already voiced your dissatisfaction with the prototype layout - doing one more round, hopefully you'll like this one better :D

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There is no software way to disable an 8087, unless you patch the executable files you are running themselves. You could add a jumper/header to your PCB though.
 
For upgrades like this, where the host pc was never intended to support 8087 and no support for hardware fault exists, is there a concern?

On my Z171, I also added an 8087 and got it to work but I'm not sure if there isna problem with doing so.
 
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