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

On 2026-08-24 07:43, c186282 wrote:
> On 8/23/26 14:28, Lars Poulsen wrote:
>> 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. 
>  >
> 
>    Yea ... threw out my last ISA-bus boards a
>    long time ago. Everyone did. Maybe a bit
>    short-sighted ........
> 
>> 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.
> 
>    You MIGHT be able to find add-on, maybe USB, adapters
>    and drivers that WILL properly emulate parallel/serial
>    ports from the old days. There ARE cheap dongles to
>    fake 9-pin serial ports, but haven't seen any of late
>    that'll do the older 25-pin ones. If you're next level
>    you could MAKE them with microcontrollers and hand-made
>    drivers (TOO old now to get that deep in again).
> 
>    The huge old "wide"-Centronics printer interface, good
>    fuckin' luck. Too bad, had a great old Epson wide
>    pin-printer with that interface - slow but insanely
>    reliable, went through endless giant boxes of the green-
>    stripe wide paper without a glitch.
> 
>    As for pin spacing .... built a bunch of devices on
>    the old Rabbit-II boards. Rabbit-III boards went from
>    3mm spacing to 2mm spacing - too tiny for mere humans
>    to work with conveniently with ordinary dremel-presses
>    and soldering irons.
> 
>    Sad, the Rabbits were GOOD boards (STILL sold BTW)
>    but had to drop 'em.

But those usb adapters can't do something the real rs232 or parallel 
port can do: directly interrupt and get processed within a known time, 
so much so as to sync clock to a GPS receiver.

I wonder if you can connect two machines via parallel port cable and 
emulated port.

-- 
Cheers, Carlos.
ES🇪🇸, EU🇪🇺;