1989 fujitsu fm towns - a cdrom based operating system called towns os where the user uses floppy disks and memory cards to store data. #retrocomputing #vintagecomputing #1980s #vintage #showa
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Time to cast a wider net, but I'm not a fan of the "throw 58 hashtags at it to see what sticks" shotgun approach, so I'll just ask the handful of #PERQ nuts still around to look to their left, look to their right, and point out the person who might have the PNX sources or documentation I seek. (If it's neither of them, maybe it's YOU! Go get that dusty old box of 8" floppies from the back of that shelf and bust out the Catweasel.)
Because surely someone, somewhere, remembers SERC, the 1980s, Chilton, RAL, ICL Dalkieth, PNX, etc. -- and squirreled away some docs, or diskettes, or even a whole PERQ with *some* information about the "C-Codes" instruction set and virtual C machine architecture of PNX. NMOC? Bletchley Park? Beuller? Anyone? There can't possibly still be concerns about throwing a copy of the sources over the transom 40 years on for research and preservation.
In the meantime, reverse engineering the kernel's microcode debugger is arduous and painstaking. Here's where we're at after a floppy or hard disk boot: both halt in a similar manner, somewhere at or before attempting to tekload the updated Z80 firmware. I'll get there, eventually, through sheer doggedness. But PNX kernel hackers of yore, lurking in #vintagecomputing, long free of ICL's closed-source bloody-mindedness, chime in anytime. :-)
lamp testing on the remains of PDP-6 sn 4 with @aap simulator to replace some bad lights. running Terry Winograd’s SHRDLU under Type 340 simulation.
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Slowly getting pieces for my IBM 5160 XT build. Got an IBM Model F keyboard I need to clean up. Trying to decide if I want to remove the Wordperfect cheat sheet.
Also forgot how heavy these were. Built like a tank and weighs quite a bit.
The PDP-10 that is a KL10 that is a DECSYSTEM-20 was so loud, it would put a smile on anyone's face in it's proximity to the marketing department.
Microsoft had one installed at the Bellevue, WA office known as "Heating Plant" or HEAT.
This is the early configuration of what the DEC PDP-6 was to become. originally the console was crammed into half the space for production, similar to the style of the PDP-5. The type 340 display remained mounted in bay 1 for the first production unit.
Always make sure you park your hard drive before shutting down at the end of the day. This would probably be one of the reasons that so many of these hard drives don't work anymore, because people forgot to park them before shutting down and transporting. #retrocomputing #vintagecomputing
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Meanwhile, the A502/16 is ready for its first "smoke" test: after checking for a complete GND / +5V short, I plugged it into a current-limited bench power-supply, and it seems to sink 160mA (0.8W). Seems sane.
I don't have an Amiga 500 here in Tokyo, but I'll take the board with me on my next trip to Italy and hopefully it will work just fine (aside for the missing realtime clock, if you care about it).
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I used hot air at 400°C to desolder the most corroded chip, and noticed while cleaning the goo off the pads that one of them was completely gone.
The damaged pin happens to be the D line (the only data bit of this 512Kx1 DRAM). So I reconnected it to a trace on the bottom by threading hair thin transformer wire through the original vias 
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The other card has no obvious vendor name other than a typoed "MAED IN TAIWAN" notice on the silkscreen.
This is the first 512K expansion card I see using SMD 256Kx1 RAM chips. The bottom side is also badly corroded and might require reconstructing a few traces with transformer wire (which I have already bought just in case).
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My other friend from Tokyo gave me a couple more of these corroded A501 clones for soldering practice.
He told me that they're not worth rescuing, but I'm still being careful to avoid further damage and possibly reapair them.
The first one is this A502/16, very similar to the Commodore design. The corroded RTC socket in the front easily came off with the hot air gun, but unclogging the holes required high temperature and damaged some of the corroded pads.
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I had never seen a real A501 before. several cheap 512KB expansions circulated in the late 80's and early 90's.
Back in January, an Italian friend gave me this obscure clone made in Italy by Tecnodata, with a leaky Varta still attached 
This card isn't even listed in Amiga Hardware Database, and I couldn't find any information on it.
After some scrubbing I got it to work briefly. Then the #Amiga 500 crashed and now it won't detect the RAM at boot 
At last night's Tokyo Hackerspace open night, a friend came with this original #Commodore A501, a 512KB DRAM expansion for the "trapdoor" slot of the #Amiga 500:
http://amiga.resource.cx/exp/a501
Like many A501, this card has been badly corroded by the alcaline solution leaked by the Ni-Cd clock battery.
This is a very satisfying video showing the repair and revitalization process done on this vintage 40+ year old 9-inch CRT display.
"The CRT with a SECRET; Restoring a tiny 1980s monitor…"
Was given a dual floppy Mac SE recently. Powered it up tonight and could have sworn I heard a hard drive spinning up inside. Opened it up and, sure enough, a third party hard drive kit was installed. 40MB drive is no longer working, though.
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