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Is this i386 an engineering sample?

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First post, by LChackr

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I have this i386 chip (see pics) and it's clearly an early one since it has no DX designation, lacks the new logo, and only has the 1985 copyright date.

Does the "ES" mean it's an engineering sample?

The "BO" on the first line has the letter "O" and not a zero, so I don't think it's implying it's a B0 stepping.

I can't seem to find any more information about it.

Thanks!

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Reply 2 of 22, by LChackr

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Thank you! So based on that I guess it is a step B0 engineering sample. (It's weird they used the letter "O" and not a zero.)

That's great news then. Not only is it one of the early buggy 386s, it's an engineering sample too. 😀

Reply 3 of 22, by douglar

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LChackr wrote on 2020-05-30, 19:46:

Not only is it one of the early buggy 386s, it's an engineering sample too. 😀

I remember the time I suffered through an extremely long win95 install for evaluation on a 4MB PS/2 model 70 only to get

Setup Error B1: Setup has detected an 80386 processor that is not compatible with this version of Windows.
Before you can run this version of Windows, you need to upgrade your processor.
Contact your computer manufacturer for more information.

https://www.pcjs.org/blog/2015/10/27/

Never saw a BO processor though. Where did you find this CPU?

Reply 5 of 22, by myrkraverk

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derSammler wrote on 2020-05-31, 14:30:

Not only is it one of the early buggy 386s

Every non-SX 386 from Intel without the double sigma marking should be seen as buggy and safe for 16-bit software only.

Out of curiosity, can software detect these buggy CPUs somehow?

Reply 6 of 22, by Anonymous Coward

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It must have been pretty embarrassing for intel to admit that their brand new (and very expensive) 32-bit CPU could only run 16-bit code. Although everybody likes to talk about FDIV, this was a far bigger F@#% up in my opinion.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 7 of 22, by myrkraverk

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myrkraverk wrote on 2020-06-01, 13:09:
derSammler wrote on 2020-05-31, 14:30:

Not only is it one of the early buggy 386s

Every non-SX 386 from Intel without the double sigma marking should be seen as buggy and safe for 16-bit software only.

Out of curiosity, can software detect these buggy CPUs somehow?

I see the above PCjs blog has all the software tests to identify these chips; I had not read it until now.

Reply 8 of 22, by Deunan

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Anonymous Coward wrote on 2020-06-01, 13:43:

It must have been pretty embarrassing for intel to admit that their brand new (and very expensive) 32-bit CPU could only run 16-bit code. Although everybody likes to talk about FDIV, this was a far bigger F@#% up in my opinion.

It wasn't the only significant bug in 386, although most other ones could be worked around. After the FDIV though Intel finally figured out that adding some SRAM cells to microcode path and a mechanism to upload data there would let them patch the CPU rather than having to replace it, and usually with minimal perfomance cost since the instructions most likely to have bugs in them are the complex ones - and these are slow to execute anyway.

AFAIK Intel kept making 386DX in PGA package well into 2000 and they had never bothered to fix the POPA like they did for SX. Or perhaps the "fix" in SX case is just different internal timings due to narrower bus.

Reply 11 of 22, by Anonymous Coward

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You should find the 12MHz version.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 13 of 22, by debs3759

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pentiumspeed wrote on 2020-06-01, 19:01:

Also no double sigma means it has 32bit multiply bug.

Cheers,

That is not correct. The double sigma means it was tested and doesn't have the bug. If it was tested and does have the bug, it will say "16-bit software only". If it is the stepping that could be buggy but doesn't have either marking, it could be OK or it could be buggy. Later steppings had no marking as the bug had been fixed. This CPU is an early stepping that probably does have the bug.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 14 of 22, by pentiumspeed

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Ok, what is "IV" stands for?

Next question related to this bugs found in 386DX processors, what about AMD Am386 processors, did AMD fix many bugs when they cloned Intel's 386DX?

Cheers,

Great Northern aka Canada.

Reply 15 of 22, by Anonymous Coward

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IV should stand for "CMOS IV", meaning it's more advanced than "CMOS III". I can't remember what exactly all the differences are between them, but wikipedia should explain it in detail.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 17 of 22, by Horun

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Katmai500 wrote on 2020-08-26, 16:46:

You should post it on the CPU World forum.

http://www.cpu-world.com/forum/

Agree ! You may have one of the only ones that are still in the hands of someone to Document it (recyclers do not care !)

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor.

Reply 18 of 22, by LChackr

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Agree ! You may have one of the only ones that are still in the hands of someone to Document it (recyclers do not care !)

Sure. I'll post it over there tomorrow. I am really happy that I was able to snag it before a recycler or anyone else did. I want to drop it into a 386 board and see which bugs it does have. 😀

It seems like it has had an interesting life. There are a few hand-made ink markings on the ceramic that have been mostly erased. One of them reads "DAISY".

You should find the 12MHz version.

I WISH!

If it was tested and does have the bug, it will say "16-bit software only".

I also really want to find one of those chips that is officially marked like that.

This CPU is an early stepping that probably does have the bug.

Yes. The officially released B0 step 386s had a number of bugs. (It wasn't until the D-step that the 386s were solid.) So I do suspect that since this is an engineering sample of a B0 step then it should have the 32-multiply bug, among a list of others. Of course, I think that's a good thing. It's part of the history of the evolution of the 386.

Reply 19 of 22, by H3nrik V!

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LChackr wrote on 2020-08-27, 03:05:

Agree ! You may have one of the only ones that are still in the hands of someone to Document it (recyclers do not care !)

Sure. I'll post it over there tomorrow. I am really happy that I was able to snag it before a recycler or anyone else did. I want to drop it into a 386 board and see which bugs it does have. 😀

Where you even able to get it at a reasonable price, then?

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀