what operating system did the Powerbook 170 run?

It cam with OS 7.0.1, the best it could run was OS 7.6.1. Where can you get that stuff? eBay. That's about it. That Mac was discontinuted over 12 years ago. I'd be wary that it's not lacking an OS, but that the hard drive is toast.

 

I think you can download 7.5 from Apple. Copies of 7.6 are plentiful in eBay and flea markets too, tho. The 170 is black & white, right? But it is a sharp, bright screen.

As long as you're on eBay, you might look for another older powerbook so you can swap power adapters, batteries, etc.

If machines are stored in non-temperature-controlled areas, like barns, they experience bad thermal cycling each morning, including condensation which causes rust and corrosion. I'm surprised it works at all. I agree with yellow that the hard drive, and the floppy drive too, are probably ruined.

 

Here are a few things that could be helpful...

Boot/Tools floppies for System 7.5.3 (actual disk image)
Installation set for System 7.5.3 (directory)
System 7.5.5 update (directory)​

You'll need a Mac with a floppy drive and a lot of floppies (about 25). You may also need an older version of Disk Copy to move the images onto the floppies.

 

My bad, I completely forgot that you could download the older OS'. Thanks for the links and the reminders!

The downloads and also updates can also be found here:

http://www.info.apple.com/support/oldersoftwarelist.html

 

Then he'll need the System 7.0.1 boot/tools floppy.

(Why Apple doesn't include these I don't know! )

 

You can also mount all 19 images of 7.5.3, burn them to a CD on your computer, and then use the System 7.5 Network Access Floppy Disk (on that website of stuff) to install off of the CD.

Of course, that is if you have a CD drive.

You may just need to use 19 floppies... or 2 floppies. 1 is for Disk 1 and the other you keep formatting over and over and over again with 2-18. I've done that with a Windows 3.11 install. Not fun.

 

Oh, I just remembered there not be any with the 7.5.3. I had never checked out the 7.0.1 as I already had that System.

Learn something new everyday.