On Sun, 12 May 2013, BE Arnold wrote: 3" floppy, 3.25" floppy 2.9" floppy 3.9" floppy 2.5" floppy 2.8M 3.5" The great "shirt pocket disk" debate, along with George Morrow's suggestion to negotiate with the clothing industry to adjust shirt pocket sizes Floptical Drivetec 3.5" without shutter 3.5" with manual shutter (point out "pinch" arrow, and its residual presence on modern "automatic" shutters ("Oh, that's just to show which direction to put it into the drive")) brackets for mounting 3.5" drive in 5.25" bay Hard sector soft sector 300 Oersted V 600 Oersted media (360K V 12.M) IBM cards, "Honeywell" etc. 45/90 column round hole Royal/McBee edge punch System 3 mini cards aperture cards (with optical images and/or fiche) Cauzin Softstrip modern QR codes software records bound in magazines Vannevar Bush's Memex (and Goldberg's Rapid Selector that it was copied from) from the 1940s/1950s Get a bar napkin from the place where Shugart got advised to change from 8" floppies to bar napkin size. LS120 Zip Jaz Tape cartridges

On Sun, 12 May 2013, Michael B. Brutman wrote: What items do YOU suggest, that are not "easy"?

On 05/12/2013 04:12 PM, BE Arnold wrote: Magnetic cards (e.g. IBM MT/ST type or NCR CRAM) Magnetostrictive delay (e.g. PB 250) Williams tubes? Mercury delay? Thin-film (e.g. Univac 1107) Metal Tape (e.g. first Univac Uniservos) Transformer ROM (e.g. IBM S/360-40) Capacitive ROM (e.g. IBM S/360-30) IBM Photostore (i.e. IBM 1369) ...and probably a dozen more than I haven't thought about... --Chuck

On 05/13/2013 05:41 AM, BE Arnold wrote: "Won't someone think of the CHILDREN!?" One needn't actually DRINK the mercury (or even hold it in one's hand) in order to demonstrate, or even look at, a mercury delay line. I'm willing to bet that most of those schools have mercury-switch thermostats everywhere. Every school I attended did. -Dave -- Dave McGuire, AK4HZ New Kensington, PA

On Mon, 13 May 2013, Cory Smelosky wrote: I'm not familiar with any thermostat simpler than a bimetallic spiral with a vial of mercury on the end of it. Or did you mean a manual valve on a radiator, with NO thermostat?, but I didn't think that THOSE have been used in schools since I was a child. For most of the 20th century, more than half of the classrooms used a round Honeywell thermostat, which did, indeed, have a mercury switch in it. In places where those were replaced with digital, the presence of the mercury within was probably used as an excuse to make the expenditure. More so than major spills of ammonia or bleach. 10+ years ago, the college administration was considering evacuating several buildings due to a spill of a pint of Kodak Stop Bath that had been stored in a maintenance tunnel between buildings. We identified it, and explained what it was. But, the administration didn't calm down until they heard from the head teacher of the Chemistry department that it was not flammable, explosive, or a deadly toxin in miniscule amounts. The spill was right onto a floor drain. We suggested that they pour copious amounts of water into that drain to dilute it and flush it away. They declined, saying that the chemistry teacher had said that it was DANGEROUS to pour water into acid. -- Grumpy Ol' Fred cisin at xenosoft.com

On 05/13/2013 05:02 PM, Ethan Dicks wrote: ROFL!! And let's not forget that terrifying dihydrogen monoxide! -Dave -- Dave McGuire, AK4HZ New Kensington, PA

On May 13, 2013, at 2:48 PM, "Alexandre Souza" <alexandre.tabajara at gmail.com> wrote: Let's not forget molecular oxygen! Hypoxia if not enough and hyperoxia if too much! And that's just breathing...forget for a moment that it's a really good oxidizer! (duh!). In a 100% O2 atmosphere, *everything* burns. TTFN - Guy

Wow! Lovely article! Laughed out loud just reading it. The comments (not all) are worth a read as well. re, reiche On Tue, May 14, 2013 at 1:03 PM, Liam Proven <lproven at gmail.com> wrote:

Damn, I keep reading that subject line and optimistically thinking that this is being taught in schools: http://mercurylang.org/ Brazil has Lua, Australia has Mercury :-) --Toby

Believe it or not, in Brazil is worst...

On May 15, 2013, at 8:30 AM, "Alexandre Souza" <alexandre.tabajara at gmail.com> wrote: Sure. Most countries don't have to go to the extraordinary step of redefining their currency to imaginary units to stop inflation (notwithstanding the fact that most currencies are already basically imaginary units), but hey, it pretty much worked. Also, Lua is pretty great, so there's that. - Dave

On May 14, 2013, at 4:03 AM, Liam Proven <lproven at gmail.com> wrote: If you want really crazy, try FOOF (Dioxygen difluoride...O2F2). To create it heat Florine and Oxygen to 700C and cool quickly using liquid oxygen. It is *extremely* reactive even at -100C. For example liquid methane burns with a white flame when FOOF is added to it at 90K. Note: DON'T TRY THIS AT HOME! TTFN - Guy

On May 14, 2013, at 9:38 AM, BE Arnold <bearnold at outlook.com> wrote: Florine on its own is nasty stuff. FOOF takes it to 11. A really wild reaction is Hydrogen sulfide and FOOF yields 433Kcal (1812KJ). For reference Thermite releases only 851KJ. Nitroglycerin releases 1510KJ. TTFN - Guy

On May 14, 2013, at 11:51 AM, Pontus <pontus at update.uu.se> wrote: Yes, that's where I first found out about FOOF. It is *insane* stuff. TTFN - Guy

On Mon, May 13, 2013 at 4:48 PM, Alexandre Souza < alexandre.tabajara at gmail.com> wrote: Too true. Easily lethal when dihydrogen monoxide is inhaled. I'm sure it's been passed around quite often during the first of April in many scientific and nerdy journals but did you hear about the radio folks who were almost over that joke this year? (the initial report was they were fired or suspended, I just read now they were suspended). I think they went about it with something along the lines of high levels of dihydrogen monoxide was found in the city's water system system or something (I think it's probably out there on the net somewhere). Apparently the problem was that listeners who were concerned started calling the municipal water supply with questions and concerns.

On Tue, 14 May 2013, Alexandre Souza wrote: I had heard that it was because "it's illegal to make false claims about the quality of the water". Which means: the water in that area isn't water! ;) -- Cory Smelosky http://gewt.net/ Personal stuff http://gimme-sympathy.org Experiments

On Tue, 14 May 2013, Jason McBrien wrote: The current medical community is somewhat obsessive about avoidance of salt.

actually, a lot fo them over here had bimetallic strips/spirals operating either microswitches or totally open contacts. Not a mercury switch. I ahev seen thermostats with mercury switches, though. Howeer, the doorbell unit here uses what seems ot be a mercury switch (glss bulb with 2 cotnacts containing a blob of silver liquid) as the break contact in the solenoid circuit. I guess it abvoids cotnact wear. POf course mercury swityhces are totally sealed and harmless unless the glass breaks .Doesn't stop the H&S idiots compaling about them thpugh. Or th 'greens' for all they favour mercury-discahrge fluorescent lamps. Go figure. I don't know if you can stil lget new mercury-wetted relays. Lovelly things, no contact bounce and a very sharp bmeak and break. I was working on a deice using one (a telegraph test message generator) the other week, the relay was fine, thankfully Probably :-( Oh $deity... The stop bath I use is a fairly dilute solution of acetic (ethanoic) acid. It's about as harmful as that other dilute solution of acetic acid that people sprinkle on their fish and chips (at least over here, I haev no idea what you put it on). You know, vinegar. In the case of sulphuric acid, that cna be true. But not with most other acids. And certianly not with stop bath. I wonder how this idiot washes plates, etc that have had food containing vinegar on them? -tony

That was really common in schools. Not sure what year but folks 50+ probably all had similar fun with hands on mercury time at school. (I know my folks did). -----Original Message----- From: BE Arnold <bearnold at outlook.com> Sender: cctalk-bounces at classiccmp.orgDate: Mon, 13 May 2013 14:17:48 To: General Discussion: On-Topic and Off-Topic Posts<cctalk at classiccmp.org> Reply-To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Re: [cctalk] Re: I'm working on a Storage Display and need parts. On May 13, 2013, at 1:12 PM, "Dave McGuire" <mcguire at neurotica.com> wrote: In high school science class the teacher brought out a jar full of it and poured it out on the tabletop (it had an edge). We got to play with it, tried picking it up with our fingers, etc. No big deal. Thanks, Brad Arnold

On 05/13/2013 11:17 AM, BE Arnold wrote: Mercury tilt switches are some of the most reliable devices ever made. I have a sump pump with one used as a level switch. No problems at all, even after 33 years of service. Do precision relays still have mercury-wetted contacts? Or have the RoHS goons eliminated those too? --Chuck

Can you stil lget the polarised-coil ones used on telegraph lines? Really nice devices. I always thoguth it was approrpatie when a local (to me, then) elecctronics shop had a few suprlus such relays on sale. The name of the shop was 'H. Gee'. Seriously. -tony

Physticaly, either a metal can about 2.5" * 0.75" * 0.5" to mount on a PCB or a larger cylindrical can about 4" tall with an octal plug on the bottom end/ Electrically, theyr'e a murcury-wetted reed cotnact with permanent magnets to bias it (induce a magnetic olarity i nthe reed) and one or more coils around it. They are stable in both states, a currnet through te coil one way will flip the contacts one way, a current thtough the coil the other way will flip the contacts the other way. They were used on 'double curent' telegraph lines where, say, +80V is a mark and -80V is a space. They were typically good to about 200baud, and had minimal distortion (the switching time and operating current in the 2 directiosn was the same). There were, of course, non-merucry polarised relays, Carpenter, Creed and WE being the ones I've either come across or read about. But the mercury-wetted ones were generally lower distortion and faster switching. -tony

On 05/13/2013 12:56 PM, Jim Stephens wrote: I remember the very tragic case of Karen Wetterhahn's unfortunate encounter with dimethyl mercury. But isn't it a pretty good rule that most organic compounds of heavy metals are pretty nasty? Lewisite and tetraethyl lead come to mind... --Chuck

On May 13, 2013, at 5:41 AM, BE Arnold <bearnold at outlook.com> wrote: No. But Williams tubes could be considered "storage displays" in their own right, if their bit pattern were at all externally visible (to be honest, I thought the OP was asking about storage CRTs for scopes before I read the thread). - Dave

And me. I was thinking 'Does he need an EHT transformer, a storage CRT, a voltage mulitplier block , or what?' Depends on the parts. The CRT is going to be a problem, the transoformers are too (and Tektronix lied about their lifetime warrenty, they no longer honour it!). Voltage multipiers would probably have ot be rebuilt (if it;s a potted module, you'd have to make a repalcement and arrange for it to stanf the voltages invovled). Other parts are most lilely standard and seasy to get. -tony

On 05/13/2013 04:09 PM, Fred Cisin wrote: Even later storage-scope CRTs are tough to find. One of my "daily driver" oscilloscopes is a Tektronix 7834. I grabbed a spare not long ago, just in case. -Dave -- Dave McGuire, AK4HZ New Kensington, PA