[HECnet] No connectivity to arsgea 4

Moving parts are trouble, absolutely. That's why I built one of David Gesswein's MFM emulators recently to replace the original hard drives in my Pro. Then again, other parts can fail. The power inlet filter in my Pro failed spectacularly (smoke, melting, stink). Fortunately replacing that is easier than replacing an ancient hard drive. And that is a common point: many electronic things can be replaced by modern parts, while mechanical things are far more problematic. SSDs can fail, though, especially at modern densities. I recently saw a 256 GB microSD card; that boggles the mind. I wonder what the life expectancy of one of those is. SD cards certainly have write limits, so any that are written to a lot are likely to fail at some point. More quickly if they are subjected to short (one block) random access writes due to "write amplification". Modern politically correct solder can be problematic too. "Lead free" processes are less reliable than real soldering. For years, maybe still, lead free solder was not acceptable for space applications. Perhaps that has been cured by now, I don't know and don't care. (I was told quite directly by a professional "if you are required to use lead free solder, do so. If you aren't required, avoid it.") I do like SSDs. My home firewall, DECnet router, and Subversion server is a fanless (heat sink cooled industrial type) SSD based PC running Linux. Unlike its plain consumer PC predecessor, it has no objections at all to spending its life in a dusty basement. paul > On Jan 22, 2021, at 12:03 PM, Johnny Billquist <bqt at softjar.se> wrote: > > Well, I know of PDP-11 systems out in production who have been running since the early 80s. The only thing that fails is the damn RD53... > Replaced those about 20 years ago now. The rest of the machine was running just fine. At that at a steel mill, so not exactly a friendly environment. Last I heard, things were still running, but it might have been replaced by now. But anyway, it's the moving parts that cause problems. The rest usually just keep running... > > Johnny > > On 2021-01-22 17:53, Dave McGuire wrote: >> On 1/22/21 11:41 AM, Thomas DeBellis wrote: >>> 10 years used to be nearly unheard of for retail machines with moving parts. When nothing is moving, then supposedly there is nothing to burn out. >> I don't know who told you that, but he/she knows jack point squat about electronics. >> Materials migration and diffusion across junctions causes semiconductor components to fail, tin whiskers cause shorts, some types of capacitors dry out and/or have their electrolyte deteriorate or crystallize, resistors drift, heat/cool cycles cause PCB flexure resulting in cracked solder joints, corrosion in air creeps into connector pin interfaces and forces pins apart, the list goes on and on and on. >> To be fair, some of the above-listed failure modes do in fact involve things moving, though imperceptibly so, my point stands. >> -Dave > -- > Johnny Billquist || "I'm on a bus > || on a psychedelic trip > email: bqt at softjar.se || Reading murder books > pdp is alive! || tryin' to stay hip" - B. Idol