[csdvrx]

Why not replace? So you don't have downtime. If it breaks now, the system is well known (30+ years) and maintained. If it's updated to something new, everything may be off until they bring back the old system.That could be months of no classes, which would be much worse than spending money to replace.

If they do nothing now, instead of taking a bet the new system will be more stable than the old one (a bet against the 30+ years odd) you don't have to have downtime.

[hn92726819]

> is well known

No... It's known by the guy who wrote it 40 years ago that happens to still live there and want to chip in to fix it

> maintained

Well, they said parts are difficult to find now. I would not consider something with no replacement parts well maintained

> taking a bet the new system will be more stable than the old one

What? It's a gamble to leave it as it is with a bus factor of 1 and rickety old computer parts. Setting up a replacement doesn't imply this one goes away. If the new one is worse, they can have a plan to switch back to the old. If this computer catches on fire, they have to pray they can find a working replacement that the original implementor can install.

[csdvrx]

> It's known by the guy who wrote it 40 years ago that happens to still live there and want to chip in to fix it

So yes, it's well know by this person and his company. I'd be surprised if in 30 years he didn't document the system and teach it to his employees.

> Setting up a replacement doesn't imply this one goes away.

Agreed, it generally implies a replacement project that goes on for years before being declared a failure at taxpayer expense.

> Well, they said parts are difficult to find now. I would not consider something with no replacement parts well maintained

The parts are "difficult" to find, yes. So if you say there are "no replacement parts", you are moving the goalpost from "possible" to "impossible" to obtain, while they are available for money on ebay. A few thousands will get you many vintage computer parts!

BTW spares for the new system will also be necessary, if you plan to have it work for another 30 years. They may be more expansive.

> It's a gamble to leave it as it is with a bus factor of 1 and rickety old computer parts

We do not know how many employees he has, and whether the replacement parts are "rickety and old". If you are used to maintaining vintage system off ebay parts, you will see lots of perfects parts available for about everything.

> If this computer catches on fire, they have to pray they can find a working replacement that the original implementor can install.

They say they have 3 spares, so no prayer required. Documentation and backups are likely available.

I just don't understand how so many people are afraid of the existing and want to rewrite everything from scratch. Looks like Resume-Driver Development to me: good for the developer and manager, bad for the company and its clients.