Re: Legacy computer in embedded industial systems (Re: Oh Gods ...)

On 2026-08-23 06:31, The Natural Philosopher wrote:
> On 23/08/2026 14:20, Lars Poulsen wrote:
>> On 2026-08-23 04:32, Carlos E.R. wrote:
>>> On 2026-08-23 08:57, c186282 wrote:
>>>> On 8/22/26 18:35, Lawrence D’Oliveiro wrote:
>>>>> On Sat, 22 Aug 2026 08:36:42 -0400, TJ wrote:
>>>>>
>>>>>> It goes against the grain, for me at least, to send perfectly good
>>>>>> running hardware off to the recycler, just because it is
>>>>>> "experienced."
>>>>>
>>>>> CPU generations (and entire architectures) get dropped from the Linux
>>>>> kernel because they can’t find anybody to step forward and maintain
>>>>> the support for them.
>>>>>
>>>>> That is how they tell that there are so few instances of those
>>>>> particular kinds of hardware around, that essentially nobody cares
>>>>> about them any more.
>>>>
>>>>    Sad, but quite correct.
>>>>
>>>>    Really not much call to run Linux-ish stuff
>>>>    on a 386/486 these days. How many people
>>>>    still USE those old boards for ANYTHING ?
>>>>
>>>>    MAYBE a few "industrial" monitor/control
>>>>    systems ... but REALLY they oughtta upgrade.
>>>  > >    However SOME won't because it might cost a
>>>>    few dollars. They'll run the old hardware
>>>>    until it literally bursts into flames - and
>>>>    then be SCREWED for days/weeks/months. But,
>>>>    the bean-counters will TELL them they're
>>>>    saving SO much money, now .......
>>>
>>> Industrial computers may have boards, like data acquisition boards, 
>>> to interface with motors and sensors (or cameras). If you upgrade the 
>>> computer, it comes with a new operating system, so their expensive 
>>> software does not run on it. The cards probably can not be plugged 
>>> in, so they also need replacing; the new boards will probably not be 
>>> compatible with the expensive software. So finally they need to 
>>> recreate the software (hopefully the company that created it still 
>>> exists and has the source files). And maybe there are a bunch of 
>>> computers to replace.
>>>
>>> The price is no longer minor.
>>
>> What you have to do is make sure you have one or two backup hardware 
>> packages, because when the computer breaks, you won't be able to buy 
>> one that works. (Just try to find a motherboard with ISA slots today!)
> 
> https://www.directindustry.com/industrial-manufacturer/isa- 
> motherboard-255106.html
> 
>> And with custom plugin boards, it is kinda too late to have them 
>> fabbed when the system is already down. And fire it up once a year to 
>> make sure it still runs.
>>
>> That may not guarantee that you can recover, but it vastly increases 
>> your chances.
>>
>> And when you put the reserve system into service, it is time to 
>> expedite developing a replacement!
>>
>> For PC systems, the big hurdle is that old 16-bit systems allowed
>> programs to do I/O to ISA bus peripherals without kernel programming, 
>> device drivers and OS hooks. When you "modernize" that ability is 
>> lost, and you have to rebuild with much more complicated programming.
>>
> That is a function of the operating system, not the chipset

Good luck finding a motherboard with ISA bus slots. For a very long 
time, motherboards had ISA bus parallel ports and serial ports, where 
all you had to do to access them directly was to populate the footprint 
for the connector. I think those went away around 2018.

I got a handful of machines with footprint for a legacy parallel port as 
refurbs after corporate desktop replacement rounds, and brought them to 
my PCB rework guy. I was very disappointed to learn that the PCB 
manufacturer had reduced the footprint from 2.5 mm pin spacing to 2 mm 
pin spacing, making the ribbon cables used for this application not fit.

-- 
Lars Poulsen - an old geek in Santa Barbara, California