[rescue] Sun 3/80 Restoration

Bill Dorsey dorsey at lila.com
Sat Oct 5 15:17:36 CDT 2019


After a number of years of searching, I finally managed to get my hands 
on a working Sun 3/80.B  I have fond memories of the Sun 3 machines from 
my time at Sun Microsystems and the m68k processor family has long been 
a favorite of mine.B  Here's a quick summary of the steps I took to get 
it working again:

My 3/80 needed a new power supply fan and 48T02 clock calendar chip.B  
Fan replacement was easy and the new fan is much quieter than the old.B  
The 3/80 would not boot with the new 48T02 chip but fortunately several 
websites contained enough details that I was able to get the magic bytes 
programmed into it from the monitor and convince it to boot.B  It came 
with a working SCSI hard drive with SunOS 4.1, so that saved me 
considerable time.B  I bought a SCSI2SD board for it, 3D printed a case 
which mated with the quick-disconnect mount in the chassis, and got it 
formatted in no time.B  Initially I installed NetBSD 8.0 on it though 
after a few days of playing with that, I decided it was much too slow on 
the old machine.B  Logging in with SSH took several minutes and just 
generating the SSH keys took many hours.B  I might go back and try an 
older version of NetBSD someday, but installing SunOS 4.1.1 appealed 
much more to my nostalgia.B  While that proved a bit more challenging 
than I first thought, again thanks to a couple of websites (mentioned 
below) I was able to do it successfully on the third of fourth try 
solely from tape images on disk.

Finally I had the 3/80 up and running just like it was 30 years ago.B  
After a few weeks of blissful nostalgia spent remember how to configure 
everything, installing useful software packages like gcc and vim, I 
figured it would be fun to see what could be done to the hardware in 
order to sweeten its performance a bit.B  I owned a 3/60 over 30 years 
ago and I remember bumping up the clock speed from 20 to 25 MHz by 
replacing the crystal oscillator, so I wondered if I might be able to do 
the same thing with the 3/80. Long story short, I was successful in 
bumping up the CPU speed from 19.66 MHz to 24.576 MHz, though it 
required hacking the boot rom and patching the kernel before the serial 
ports worked correctly since the CPU clock is shared with the Zilog 
serial chip.B  While the machine is still painfully slow by modern 
standards, it was a satisfying project.B  It has been running 24 hours a 
day now at this speed without any issues.B  I should note that I did 
replace the CPU and FPU with 25 MHz variants and all of my memory is 60 
ns (I got parity errors when I tried 70 ns memory).

I've managed to find copies of source code for SunOS 4.1.3 and 4.1.4 and 
made a small effort to build them on the 3/80.B  However, it looks like 
the changes are a bit less superficial than I had remembered so it looks 
like it will take a more significant effort.B  In the meantime, if anyone 
can point me to a source for the 4.1.1 source code, I'd appreciate it as 
there are a few small changes I'd like to make the the kernel which 
would go a lot more smoothly if I didn't have to disassemble and patch 
it by hand.

I just read over the last year or so of postings for the list and see 
that there still appear to be a couple of people here who have Sun 3 
computers in their collection.B  Would be pleased to exchange thoughts 
with anyone still actively using these old machines.

Here are the two Sun 3 specific websites that saved me a lot of time on 
my restoration:B  sun3arc.org and sun3zoo.de.B  Big thanks to their owners 
for making all that information available online.

- Bill

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