Same. bkw
On Sat, Mar 16, 2024, 11:12 PM Gregory McGill <[email protected]> wrote: > Is the same behavior with nimh as with NiCAD? > > On Sat, Mar 16, 2024, 6:46 PM Brian K. White <[email protected]> wrote: > >> One problem with batteries for sure is you can't tell a junk future >> leaker by just looking at it. Even if the actual cells are stamped with >> a quality manufacturer name, they could be fake or they could be real >> but rejects, or they could be illegitimate extra production "after hours >> runs" from the same plant in china or wherever that makes the real ones, >> or real but aged-out old stock repackaged and sold as new etc. >> >> And there is essentially no way to detect or prove any of that by >> examining the battery in your hand. If it's visibly corroded or doesn't >> take a charge or something, you can tell that obviously, but if it >> visually looks perfect, and functions within spec, that doesn't prove >> anything except that it looks good and works today. It could be utter >> garbage that dies and leaks in 1 year or 5 years. >> >> The only hope that it will actually last the promised number of years >> before starting to leak, is to buy it from a source that you can trust >> to be very careful with their own sources. No ebay, no amazon, certainly >> no aliexpress, it must be someone who will actually care if any >> customers ever start giving them a bad reputation. >> >> I guess all that is true for caps too really, so maybe no difference on >> that front. >> >> -- >> bkw >> >> On 3/16/24 21:21, Doug Jackson wrote: >> > Every time I see one of those evil NiCad batteries, I replace it with a >> > 0.5F supercap. >> > >> > I have never had an issue with my M100, or with the Olivetti equivalent >> > (number escapes me at the moment) >> > >> > Having said that, the oldest would have been 8 years ago, so I don't >> > have the same 30years of experience regarding leaking characters. >> > >> > Doug >> > >> > On Sun, 17 Mar 2024, 11:44 am Brian K. White, <[email protected] >> > <mailto:[email protected]>> wrote: >> > >> > You can run plugged in to the wall for all normal random on/off >> > operating times without worrying about it too much, IE, all day long >> > for >> > 8 to 12 hours or whatever, and for multiple days in a row, if >> unplugged >> > when turned off. >> > >> > And you can leave it plugged in turned on or off overnight for one >> > night >> > to a few days. >> > >> > And you can even get away with exceeding those pretty badly once in >> > a while. >> > >> > What you want to avoid is plugging it in and leaving it plugged in >> 24/7 >> > for weeks or months or years, whether it's on or off. >> > >> > The harm is the charging circuit that charges the internal nicd >> battery >> > soldered on the motherboard. The battery is not a lead/acid or gel >> cell >> > that has a float value where it can just stay floating at a certain >> > value forever, and the charging circuit is not a smart modern >> battery >> > manager that knows how to stop charging when the battery is full, it >> > just keeps on supplying a bit higher voltage than the the cells own >> > voltage, and current just keeps on flowing backwards through the >> cell, >> > and sooner or later this kills the battery by a couple different >> > possible mechanisms from plain heat & pressure making it leak and >> cook >> > off all the electrolyte, to things like the electrolysis process >> like >> > electroplating, eating away all of one plate and building gunk up on >> > the >> > other. >> > >> > It's pretty forgiving so you don't have to be super careful. You can >> > *mostly* never even think about it, and a normal random usage >> pattern >> > will just naturally be fine. Just don't plug it in and forget about >> it >> > for a year. >> > >> > It doesn't touch the AA's and it doesn't matter if the machine is >> > turned >> > on or turned off. >> > >> > Now that you make me run through it all like that, I realise this >> might >> > finally be be an actual valid useful reason to install a supercap >> > instead of a new nimh cell. >> > >> > Mostly there is no point, because both a cap and a battery will only >> > last about the same number of years, and both will start to leak >> > corrosive juice after about the same number of years. A cap is not >> > harmed by being allowed to go all the way dead (which a battery is), >> > nor >> > by being allowed to stay dead for a long time (extra especially bad >> for >> > a battery), but even a battery that has been so badly treated still >> > supplies more standby time than a brand new perfect cap. All in >> all, no >> > point. >> > >> > But one difference that matters, a cap should not be harmed by the >> > crudeness of the charging circuit. A cap will just charge up and >> stop >> > conducting and won't care about the charging supply at all. No >> current >> > will keep flowing through the cap, no cooking or electrolysis etc. >> > >> > I have always been very much not in the supercap camp, but this is >> one >> > real thing. >> > >> > -- >> > bkw >> > >> > On 3/16/24 16:33, Will Senn wrote: >> > > Wow, Brian! Super clear. Now, I want a REX# :). >> > > >> > > When you say that leaving it plugged in will kill the battery, do >> > you >> > > mean that I should run it off AA batteries most of the time and >> > not my >> > > 6v 200ma adapter? And the battery you're talking about killing is >> > the >> > > nicad on the board, right? >> > > >> > > Thanks, >> > > >> > > Will >> > > >> > > >> > > On 3/16/24 3:21 PM, Brian K. White wrote: >> > >> I summarize REX as: "An on-board software-controlled option rom >> > >> library and ram image library." >> > >> >> > >> That's the shortest way I've found to say what it does, but >> > that's not >> > >> the same as saying what it's good for or why you want one. >> > >> >> > >> Because of the particular features and limitations of a M100, >> > probably >> > >> the single most life-improving thing you can do to one is to >> have >> > >> TS-DOS in ROM. >> > >> >> > >> That one thing addresses a few different pain points. >> > >> >> > >> The biggest pain points of a M100 are: >> > >> >> > >> - Battery-backed ram only storage. Very little storage, and >> easily >> > >> erased or corrupted, either by dead batteries or a software >> crash. >> > >> >> > >> - The way in manages machine-language software. How they all >> > want to >> > >> run in the same place in ram, yet the OS does not provide very >> > much in >> > >> the way of automatically moving programs into and out of that >> > spot, so >> > >> software is always clobbering other software, or you limit >> > yourself to >> > >> just having a single machine language app installed, or you >> have to >> > >> figure out the arcane way to hack the binaries to relocate them >> > to run >> > >> at different addresses side by side, or you have to keep double >> > copies >> > >> of binaries so that the running copy can get clobbered and later >> > >> replaced from the ram file copy... >> > >> >> > >> - The main rom provides no binary file transfer other than the >> > >> cassette. And no *convenient* file transfer even for text. >> > >> >> > >> These things combine to make life kind of difficult. For >> > instance you >> > >> want some better file transfer app, but since you have no binary >> > file >> > >> transfer to begin with getting the file transfer app itself >> > installed >> > >> is a pain. Then once it's installed, it consumes precious ram, >> > and is >> > >> easily broken because of the way machine language apps are are >> run, >> > >> and the simplest way to address that is to have a 2nd physical >> > copy in >> > >> ram, which uses up yet more of that precious 32k. etc. >> > >> >> > >> Having any tpdd client at all installed in any form makes >> > transferring >> > >> files a breeze, including binary files. This somewhat alleviates >> > the >> > >> small ram problem because you can easily put files away and get >> > them >> > >> back, as long as your tpdd software stays working. >> > >> >> > >> Even better is having a full featured tpdd client like ts-dos >> > instead >> > >> of teeny, and having it in rom instead of ram. >> > >> >> > >> That alleviates all kinds of annoyances. >> > >> - It consumes almost no ram. >> > >> - It doesn't require a pain in the neck bootstrap/loader >> process to >> > >> get installed. >> > >> - It isn't subject to being clobbered and needing to be >> reinstalled >> > >> because of some other software writing over it or crashing. >> > >> - It isn't lost after a hard reset or dead batteries. >> > >> >> > >> With TS-DOS in rom, you can pick up a totally dead machine, or >> > totally >> > >> kill your machine with a hard reset on purpose, or suffer a >> > total ram >> > >> corruption from buggy software, and with just "CALL 63012" you >> > are up >> > >> and running again, connect to a computer and pull down files. >> > >> >> > >> But even though this makes a lot of things a lot better, this >> still >> > >> needs a computer and serial cable. The tpdd client just makes >> it so >> > >> that you can effortlessly connect to a pc and move files back & >> > forth, >> > >> and having it in rom just means you can effortlessly always have >> > the >> > >> tpdd client regardless of crashes or dead batteries. >> > >> >> > >> That still leaves a couple things that could be better: >> > >> - If you had a plain ts-dos option rom, it means you can't use >> any >> > >> other option rom because the single socket is occupied already >> > by ts-dos. >> > >> - You still need a serial cable and pc (or a real tpdd drive or >> a >> > >> Backpack or PDDuino) to actually get the files from somewhere / >> put >> > >> them somewhere. >> > >> >> > >> REX gives you ts-dos in rom just for starters. It gives you >> > ts-dos in >> > >> rom which just that right there alleviates several things above, >> > but >> > >> also: >> > >> >> > >> - all other options roms besides ts-dos >> > >> - full ram image backups >> > >> - all on-device self-contained with no computer or serial cable >> > needed >> > >> (after initial loading) >> > >> - impervious to dead batteries or resets or crashes >> > >> >> > >> And although you do need a computer to install option rom images >> > onto >> > >> the rex one time, ts-dos in particular is pre-installed, so that >> > >> single most-needed one never needs even the initial one-time >> > install >> > >> from a computer. Only all the other roms need to be loaded from >> > a pc >> > >> once. And the loading process is easy, because REXMGR uses tpdd >> > >> protocol internally to pull the rom images from a pc. No >> > >> bootstrapper/loader procedure. >> > >> >> > >> The other option roms give you mostly a few different office >> > software >> > >> kits, ie spreadsheets and word processors, and a few other >> > things like >> > >> there is a FORTH rom and an assembler/debugger/renumberer. >> > >> >> > >> The ram image backups give you essentially more copies of 32k >> > ram. It >> > >> helps a few different ways: >> > >> - you can physically hold more than 32k of apps or data. >> > >> - you can recover from a dead battery or reset or corrupted ram >> > from >> > >> crashed software by restoring a ram image. >> > >> >> > >> There are something like 30 or so available slots, and each slot >> > can >> > >> be either an option rom or a ram image. That's a lot. >> > >> >> > >> All without a computer. In the coffee shop, on the train etc, >> just >> > >> recover from dead zero in a few seconds. Just "Call 63012" and >> away >> > >> you go, all interactive app and menu driven after that. >> > >> >> > >> So that is why you want a REX of any stripe, REX Classic, REX#, >> or >> > >> REXCPM. >> > >> >> > >> Now for REXCPM in particular.... >> > >> >> > >> Those particular advantages are something the REXCPM is less >> > good for. >> > >> >> > >> REXCPM does give you all of that, but only as long as the M100 >> > >> internal battery is not dead and the REXCPM and bus adapter >> board >> > >> remain installed in both sockets. >> > >> >> > >> You can recover from software crashes that scramble the ram, and >> > from >> > >> intentional hard resets that wipe all ram (ctrl-break-reset), >> > but not >> > >> from dead batteries or switching off the memory power switch on >> the >> > >> bottom for more than a few minutes, or removing the device from >> the >> > >> m100 for more than a few minutes. >> > >> >> > >> If the M100 internal battery runs out, or you uninstall it for >> more >> > >> than a few minutes (you do get a pretty good grace period of >> > several >> > >> minutes, maybe even over 10 minutes) then you have to reload the >> > >> REXCPM from scratch as you just experienced. If you had a REX >> > Classic >> > >> or REX# instead of REXCPM, all you would have done is type "call >> > >> 63012" and you'd be all back up & running. No pc, no "37 easy >> > steps". >> > >> Done. And to remember "call 63012" just write it on a sticker or >> > >> label-maker on the bottom. Put it on the underside of the option >> > rom >> > >> or battery cover if you want to hide it but then you have to at >> > least >> > >> remember that it's there. >> > >> >> > >> I did make a "UPS" for REXCPM that should keep it alive for a >> few >> > >> years, but it's pretty involved to build and ultimately hard to >> > justify. >> > >> I don't pretend it's practical for most people, but it does work >> > and >> > >> exists. >> > >> https://github.com/bkw777/REXCPM_UPS >> > <https://github.com/bkw777/REXCPM_UPS> >> > >> >> > >> You have to buy the parts from digikey or mouser etc, order pcbs >> > from >> > >> elecrow or oshpark etc, and then it's a pretty fiddly soldering >> > job, >> > >> and it ends up costing as much or more than the rexcpm itself >> > just to >> > >> give it a battery. And for all that, I think I only estimated 6 >> > months >> > >> per cell x 4 cells = 2 years, but that's after the M100's own >> > >> batteries run out, and if you have fresh alkaline AA's and a >> > charged >> > >> internal battery, the M100 itself can last anywhere from a few >> > months >> > >> to a year. So maybe up to 3 years? >> > >> >> > >> A better long-term solution would be a keeper. You remove the >> > rexcpm >> > >> and plug it in to something with socket and a big battery. But >> that >> > >> doesn't help with one that's installed in a machine. You'd need >> to >> > >> remove it from the machine to put it in the keeper. Plus the >> molex >> > >> sockets are no longer made. There are a few around available >> > still but >> > >> this would be a wasteful way to use one up instead of keeping >> > them to >> > >> repair machines. Really, for the long term like over 5 years, >> it's >> > >> probably more practical to just let it die and reload it. With a >> > >> convenient bootstrapper and tpdd server on a pc, it only takes a >> > few >> > >> minutes to reload a rexcpm from scratch. It's several steps that >> > >> requires a cheat sheet to follow, but none are very difficult or >> > long. >> > >> The hard part is just deciphering the original directions to >> figure >> > >> out what actually are the steps you need to do. >> > >> >> > >> So all in all, I'm not sure how necessary the ups is. It's >> probably >> > >> more practical to just do 2 things to live a happy life with a >> > REXCPM: >> > >> >> > >> 1 - Keep it installed in a machine. And keep that machine >> charged. >> > >> (Unfortunately, you can't just lave the machine plugged in to >> > the wall >> > >> 24/7 for months, that will cook the internal battery.) >> > >> >> > >> 2 - Get good at reinstalling it. It's several steps, but it's >> > possible >> > >> to write a little cheat sheet that is easier to follow than the >> > full >> > >> original documentation. And none of the steps are very >> difficult or >> > >> long. You don't even need the cheat sheet after a few runs >> through. >> > >> >> > >> If you aren't specifically wanting to run CP/M then I always >> say a >> > >> REX# is far more practical. REX# is an nvram device that acts >> > like a rom. >> > >> >> > >> Instead of ever needing to recover the REX, the REX is what >> > recovers >> > >> your M100. >> > >> >> > > >> > >> > -- >> > bkw >> > >> >> -- >> bkw >> >>
