What connector, on what motherboards to look for it?

Question

Iron

There is a board, a very old device clings to it via VGA, the software for which lies on floppy disks and dates back to 1999. I need to buy a very old computer, for this I need to determine what connector should be in the motherboard for this thing to fit, and in which Pentiums or even older computers this is most common.

Answer 1

Eh...
So a generation has grown up that doesn't know what the ISA bus is :) Not writing ports and interrupts on network cards with a marker (because forgetting this setting, if it was done - hell and demons, there were always 3-5- 10 settings program that read various cards), which did not turn the knobs in the BIOS to make this balalaika work ...
It was recently, it was a long time ago ...
At the beginning of the 2000s, mothers were still produced with one ISA connector at the very bottom, usually 4-5 PCI + 1 ISA. Socket 370 if memory serves. Finding something workable now, and even considering that the photo apparently shows an internal modem (in those days, the so-called "softmodems" were very often made, by analogy with the current "softtrades") - the probability is a little more than none.
JFYI: This bus is still quite alive in industrial automation devices

Answer 2

Similar to ISA Slot . But this is an old thing, which back in 1997 was considered obsolete.