Archive for November, 2017

16
Nov
17

SS20 Desktop: Some minor progress

Whilst it has been some time since the original post, I have been a busy beaver trying to get the old Sparcstation 20 running. I’ve been making an effort to get the hardware working with some mixed success, and have made much better progress with the software.

The hardware is of course the much more pressing matter for obvious reasons. I had a recurrence of the problem I had with stack under run errors and just general problems booting in general. Of course this lead me to suspect the hardware, so this week I went about trying to work out what exactly was causing the issue. One way to help determine which part is at fault is by stripping the system back to the minimal and gradually add components while testing the system in between. Having removed most components the stack under run symptom didn’t disappear, trying each memory stick individually didn’t improve things, so I began to fear the worst as surely not all the RAM I have is faulty. It was at this point I decided to run the set-defaults command to reset the computers configuration despite not seeing anything there that should cause any issues, this funnily enough seemed to do the trick, as far as getting the machine to the open boot prompt without any errors and passing all the diagnostic tests with everything installed. I had to scale back to a 17G fujitsu HDD as the larger one didn’t cooperate with the system.

At this point I breathed a big sigh of relief as my hardware is probably in working condition. It’s booting the OS (NetBSD 7.1) and seems to run fine with one problem. Random system hangs. There doesn’t seem to be any pattern such as when the machine is loaded down or network access. I’m guessing that the kernel is having some issue and tries to hand control back to the system ROM, but this some how hangs/fails. I might try running the machine with out the X server in case it is stopping any errors from being displayed. I looked into the kernel messages and noted a few devices that may also be the culprit. The kernel is detecting the on board graphics (comes up as sx0 in the messages) even though I do not have a VSIMM installed, as I’m using a SBUS graphic board instead. The audio chip in my machine is listed as a DBRI, which is known to have issues with the current kernel driver. If you try to play audio in any manner the system hangs, it’s been a bug for a while, it kinda worked under NetBSD 4.0 when I last had that running. With this in mind I’m building my own kernel with the drivers for these two devices and other unnecessary devices removed.

I’ve had much more luck getting software to build in my emulated machine. I’ve got a fairly large collection of software to try out. Although I did have trouble much earlier on when either QEMU or the emulated machine would hang during a build. I can’t be sure if that’s down to the emulation or if it’s a genuine issue with the OS, and a possible cause of my problems on the real machine. Whilst I haven’t really changed anything in the emulation, it hasn’t hung for quite a while, so it’s any bodies guess as to the cause when it did happen.

Progress has been slow, but I’m gradually getting there! I’ve seen some cheap Ross Hypersparc 90Mhz modules that I’m considering buying as an upgrade.

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