First question you need to answer is what do you want to do with the machine because your hardware options vary depending on if you want to run SunOS, Solaris, NextStep, or NetBSD. You also need to know how much you care about 24bit graphics and for what OS. If you don't care about SunOS and NextStep buy an ultra sparc, they're cheap, fast, and easy to get 24bit framebuffers for them. If you do care about NextStep and want 24bit graphics get an ss20 and a vsimm but be prepared to pay for them. If you don't care about 24bits get an ss10, it's almost as good but no SX or built in audio but they are pretty cheap on ebay these days. If you want 24bits on SunOS you're a true collector and better have patients and money cause your options are very limited. You can also go for an ss4/5, both are fully supported by Solaris, NetBSD, NextStep (no turbosparc). The s24 framebuffer for the ss5 while 24bits is not very fast and just not a very good card in general. There's one on ebay for $50 right now and honestly I'm not sure if it's even worth that much. SunOS does not support the graphics on these machines but otherwise works fine. Voyager and JavaStation are both rare collector items, don't bother unless you have deep pockets. All other machines are not supported by NextStep but will work fine on everything else. If you don't need 24bit graphics than cgsix are cheap and plentiful on ebay and supported by everything.

One word of warning: a lot of the trim (particularly the purple wavy bits) of the SS5/SS20/US1 era was made with crappy ABS plastic that simply disintegrates over time.

I have an SS20 which was pristine when I got it 4 years ago, but just opening up the case caused most of the trim to crumble into nothingness. I consider the design of the later SS5/SS20 pizza boxes to be some of the greatest in computing, but ironically with the state of the materials I'd recommend the other designs without the purple bits as they are far less fragile.

For me the ultimate SPARC is the SS20, with its incredible expandability given the tiny form factor.

That said, I wouldn't run NetBSD on it. Yes, it will run, but it will be painfully slow once you do anything more than just show a console. I have Solaris 7 on mine, which runs fine - in the past I even had Solaris 9 on it, although that was pushing it. However I intend to downgrade to Solaris 2.x because I have a SunPC I would like to play with. I've just not had any luck with install media for that yet. Consequence is that I have to treat this as a vintage, insecure system with no direct internet access. But if I have to choose between the full 1990s Solaris experience vs whatever experience modern NetBSD will do on ancient hardware, I'd definitely choose the former. Even a Raspberry Pi would work far better on a modern OS.

So, I'm invested in my SS20. I'd say SS10 is slightly more limited but at least won't fall apart the instant you look at it. The difference in performance is irrelevant this far in the past.

I would agree with putting Solaris on them, which would present the least difficulty, though even that could be a struggle.

I'm not sure of those specific models but from my research on later-90s Sun machines (I was looking into procuring an Ultra) - you'll probably need a specific Sun keyboard and mouse which can be just as difficult to find and costly for what it is. Other integrated ports could also be problematic.

Also (again, not sure if this applies to all the models you listed) most likely the NVRAM battery is shot and would need to get replaced and / or heavily modified for a more modular solution (videos on youtubes). Otherwise you have to manually set the NVRAM at each boot, though I'm not sure exactly what will or wont work without this config info, I forgot since its been so long.

drosse1meyer wrote on 2023-03-30, 15:32:

I would agree with putting Solaris on them, which would present the least difficulty, though even that could be a struggle.

I'm not sure of those specific models but from my research on later-90s Sun machines (I was looking into procuring an Ultra) - you'll probably need a specific Sun keyboard and mouse which can be just as difficult to find and costly for what it is. Other integrated ports could also be problematic.

Also (again, not sure if this applies to all the models you listed) most likely the NVRAM battery is shot and would need to get replaced and / or heavily modified for a more modular solution (videos on youtubes). Otherwise you have to manually set the NVRAM at each boot, though I'm not sure exactly what will or wont work without this config info, I forgot since its been so long.

Many old KVM switches do protocol translation, allowing you to use a PS/2 keyboard and mouse with Sparcstations etc. Could be useful to know if you have a hard time finding Sun peripherals.

I particularly like the Blackbox brand. Awesome quality, hassle free, and I've yet to see one of their manuals not containing specs/wiring diagrams for the cables needed to hook up different systems.

I've got a couple of SPARCstation 4/5/20 and never had any trouble with the purple trim on them - it's all quite solid still. Perhaps sun exposure matters? The tabs on the front of the lid however - those are broken off on some machines.

As for which machine?

• If you want a SPARCstation 20 you'll really want to get one with at least two CPUs and a VSIMM to enable the SX framebuffer (the onboard 13W3 video port) otherwise there is kind of no point. Multiple CPUs and the SX framebuffer were pretty much the reason to get one of those machines over the cheaper SPARCstation 5 AFAIK. From what I've seen MBus modules and VSIMMs (and SPARCstation 20s themselves) are quite expensive on ebay so I wouldn't count on being able to upgrade one of these machines for anything resembling a reasonable price - my SPARCstation 20 will likely forever remain a bottom of the line uniprocessor machine with budget CGSIX graphics.
• The SPARCstation 5 is pretty much just a SPARCstation 20 without the MBUS slots (so only one CPU), no VSIMM slots or SX framebuffer, and one less SBus slot. It adds an AFX slot for the optional S24/TCX framebuffer which is sort of the predecessor to the UPA/Creator cards found on the Ultra series.
• And the SPARCstation 4 is pretty much just a SPARCstation 5 with no onboard audio (it's an optional card), one fewer hard disk slot, goes down to one SBus slot but has a lower-end onboard 8bit version of the TCX framebuffer (which frees up the one SBus slot for other things).
• The lunchbox SPARC machines are cute and conveniently small, though not fast. But then no SPARCstation is fast by modern standards. I quite like them. The MiniDIN serial ports on these use the same pinout as classic Macs making adapters relatively easy to find. Not all models have 10baseT so you may need an ethernet MAU.
• The Ultra series might be worth looking at too - most of these should still be supported by Linux if thats of interest. The Ultra 1 and Ultra 2 still use SBus expansion slots. The Creator models replace one SBus slot with a UPA slot for a special Creator accelerated framebuffer card and also bump the ethernet up to 10/100 and upgrade the SCSI interface too. So the Creator models are worthwhile even if the UPA graphics card is missing.
• The rest of the Ultra series use PCI for expansion, VGA ports (unless you've got a Creator3D card installed) so you can use a normal monitor and may have IDE instead of SCSI. The PCI slots mean you can get a SunPCi - basically a PC on a PCI expansion card to let you run Windows in a Window under Solaris. The first generation card (for the Ultra 5 and 10) has AMD K6-II at 300 or 400MHz, a VGA port (so you can use an external monitor instead), USB, Audio (ESS AudioDrive), serial and parallel ports. IDE drives and the floppy drive are emulated by the SunPC software. Kind of fun. Apparently the VGA emulation isn't perfect so for playing DOS games you'd want to hook up an external monitor.

Most SPARC machines need a special Sun keyboard and mouse, though newer machines (the Blade series and newer Ultras at least) use USB instead though ideally you'd still have the appropriate type 6 or 7 USB keyboard. If you don't have a keyboard plugged in system will assume you're running it headless and output everything to the first Serial port instead. So you don't need the special keyboard to use a SPARCstation - it's only necessary if you want to plug a monitor in rather than use it over the network.

You'd probably want an external SCSI CD-ROM drive supporting 512 byte sectors with appropriate cables and terminators if it's not a newer machine with IDE. The lunchbox machines of course have no 5.25" bay for an internal drive, and many of the 4/5/20 machines require a special low profile CD-ROM drive so if there isn't already one installed you may have a hard time finding one that will fit. All machines can network boot though so if you don't have a CD-ROM drive you can still get an OS on that way.

All SPARC machines of this era use an NVRAM chip that has a limited lifespan. These machines store their ethernet MAC address and Host ID in the NVRAM chip so if that's not working a lot of machines will simply refuse to boot. On some (but not all) models you can just replace the chip with a new one (its socketed) but make sure its an actual brand new one from a reputable supplier - not some "new" one from ebay thats been sitting on a shelf for years and has a half-flat battery. Alternatively you can slice into the side of the chip and wire in a new battery which is what I do as the replacement NVRAM chips are not cheap. If the NVRAM chip is still good check there is no firmware password set as bypassing these can be a bit of a pain if you don't want to replace the NVRAM chip.

If you go for one of the lunchbox form-factor machines (SPARCstation IPC, IPX, LX, XZ, SPARCclassic, SPARCclassic X) you will have to recap the power supply sooner or later. Preferably sooner - don't wait for it to stop working. If possible inspect the machine first and check for an unpleasant fishy smell or rust on the power supply cover as this could indicate the capacitors have already started leaking their corrosive electrolyte. Recapping these PSUs isn't hard so it's not a reason not to buy one (I've got two and would like more), it's just a (I hope) one-off maintenance task you'll have to do like dealing with the NVRAM chip. The job is much easier if you do it before the capacitors start leaking.

I can probably answer more specific questions or provide further detail on anything if required as this is all quite fresh in my mind right now. I'm currently going through my SPARCs trying to fix what doesn't work, then benchmarking and installing Solaris on what does work:

davidrg wrote on 2023-03-30, 21:39:

I can probably answer more specific questions or provide further detail on anything if required as this is all quite fresh in my mind right now. I'm currently going through my SPARCs trying to fix what doesn't work, then benchmarking and installing Solaris on what does work:

Good info

Also that's quite a collection 😀