At 5:44 PM -0400 10/24/12, Sridhar Ayengar wrote: LOL! Well I guess it has the advantage of being 'bug free'. :-) I find myself tempted to turn on my Commodore 64 and try it. BTW, I'm quite happy to report that as part of the project to redo my darkroom, I've set my Commodore 64 back up (yes, in the darkroom area). In fact part of the time I was supposed to be working on the Darkroom last Saturday I was actually playing a game on the C64. :-) Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com | OpenVMS Enthusiast | | | Photographer | +----------------------------------+----------------------------+ | My flickr Photostream | | http://www.flickr.com/photos/33848088 at N03/ | | My Photography Website | | http://www.zanesphotography.com |

My first program was: 10 GOSUB 10 20 END This was on an HP 2000C Timeshared Basic System sometime in 1975-ish. The END was there because a program wouldn't run on this system if there wasn't an END statement. After a little while, the program halted with an error, something about GOSUB with no RETURN, IIRC. It's interesting to try this on various different BASICs as it does create a situation where, if the bounds checking on the stack containing the return statement numbers/pointers isn't good, you can cause "interesting" things to happen. There are a few BASICs I've tried this on where the program will actually crash BASIC. Rick

WHAT "return" statement??!? Anything otyher than JMP $ is BROKEN! On Thu, 25 Oct 2012, Ethan Dicks wrote: So, you can't even do: 10 PRINT "Welcome to DOS!" 20 PRINT "C:\DERP> "; 30 INPUT A$ 40 PRINT "Bad command od filename" 50 GOTO 20 60 END Is THAT why operating systems aren't written in BASIC? :-)

On Thu, 25 Oct 2012, Mouse wrote: They had to clean up the typos and spelling for the IBM release.

Not so. Both of the above programs produced an error message on one of the machines here. A machien that has a BAISC interpretter in ROM. The problem is that the HP9830 BASIC (and others I guess) _require_ an END as the last statement of the program. Are you planning on using the C64 as an enlarger timer or soemthing? IIRC 'Cotnrol the World with HPIL' has an enlarger meter/timer based on one of the hP handhelds (HP41?) One of Thomas Tomosy's books on camera repair has a chutter testing timer based on a C64 with a photosensoe conencted ot the joystick port. -tony

My DeVere 504 has the original electronic timer which looks a lot more fanct than it is. You set the tiem with a couple of rotary swithces on top. But it's not a digital circuit, dividing down a master clock. It's just a 555 monotstable, the switches vary the number of resisotrs in-circuit. Fortunately the DeVere system is quite modular, the timer plugs into the votlage stabiiser, and one of the first things I did when I got the enlarger was to trace out schematics. So I can make a digital timer to plug into the smae socket if I want to. THere are at lest 6 books. Two of them are brand-specifc -- Leica and Nikon (note the latterc covers the S series ragefinder camers, the reflex cameras and the Nikonos). The otehr 4 books are more general. Camera Maintenance and Repair VOlumes 1 and 2 have gneral repair tips, methods and how to make test instruments in the first half of the book and then some details on taking apart 'representative' models. Restoring Classic and Collectable coamers covers pre-war camers, how to mke bellows, tc. Repairing the Great Collectable Camers is post-war models and covers some very interesting designs. None of them, IMHO, are a substitue for the manufacturer's service manual -- if you cna get it. And there are plenty of thigns I would do differently. But the books are worth reading. Make one! Although there is a trap for the unwary that most comemrical testers get erogn too. The point is that no shutter opens and closes instaneously. Not even folca plane shuytters -- due to the spacing between the curtains and the flim, you get a slight penumbra round the slit image. So while you would like the light .vs. time curve to be a rectangle with vertical sides (along the 'light' axis), in fact it has sloping sides (which may, or may not, be linear). Now, what actually matters, to a very good apporxiamtion, is the integral of that curcve, the area under it. So what you should do is integrate the light coming throug hthe shutter and compute the equivanet 'open time for a perfect shutter'. What most, if not all, testers do is simply set a light threshold and measure the time for light to be above that threshold. This is fine for slow speeds, it can give wildly wrong resutls for high speeds (and can cause people to complain that the shutter is not accurate, when in fact the totla ligth transmitted is correct for the marked time). However, such a simple tester will pick up gross probles, like a sticking escapemet. Just don't expect the higher speeds on the shutter dial to agree with the timer. If in doubt, take a series of photographs of the same illuminated grey card with different speeds, adjustign the aperture to give the same exposure each time, and compare the densities of the negatives. That will pick up any major erors in one of the speeds. -tony

They are rather more ocmmon over here, as you said, it's an English company,. I think they have been taken over now, but anyway. I have an old 504. IT's built like a tank, a rigic cast frame, with adjustable gib strips on the head slide, so you can take up wear. About the only thing to go wrong with it are the bellows. Ihave the Dichromat colour head. Again, it's nice and simple. The votlage stabviliser and timer are all standard parts, I can fix them. Oh, the 504 goes up to 5*4" negatives, and down, of course to subminiature if you want to. It uses standed 'Leica Thread' lenses of course. It's certainly in 'Camera Maintenance and Repair Volume 1', I have just looked. I haev no idea if it's in any older single-volume version I haev all 6 books. Thew one I find most useful is 'Repairng the Great Collectable Cameras'. Amaszingly, about the time I got it, a local camera shop started to get in for sale second-hand examples of perhaps 50% of the cameras in that book. I bought a fair number of them. The Leica and Nikon books are interesting, but I regard those cameras as being worth buing the service manuals for. You might find the Nikon book interesting, just to see what is involved. Thanks, I will take a look, even if it means a trip to an internet cafe. There is a UK-based company Oldtimercmaeras, who sell copies of such things. THey are not cheap, but then messing up a camera is not cheap either. I can't afford them for the simpler cameras I own, ones I guess I can fix anyway, but I am sure glad I bought the manuals for my Nikon F and F2 stuff. And the manual for the MD2 motordrive is useful. Although Nikon only suppllied the ocmplete control PCB as a spare part, the manual includes the scheamtisc and component details. It's hjandy if you wnt to work out your own devices to link to the motordrive connectors too. [Shutter speed tersters] I wil ltake a look. In general I prefer a standalone instrument, rather than one that involves asettign u pa computer and monuitor, but anyway. I plan to make a more genral speed tester to check things like curtain travel time in a focal plane sutters, whether such shuttersare 'capping' (closing inside the frame area), checking sync swtich timing, and so on. A lot of old leaf shutters are. The one thing not to do is try to 'improve' things by filing or punchiong the edge of the speed cam. It was right one, it will not wear. Most of the time it's gummy lubricants. I take the darn thing apart and clean the bits in solvent, wiming them clean, and repeating. Then relubricate with watch oile or similar, but only in the right places. Tomosy's books givea good tip IMHO. Buy a cheap leaf-shuttered 35mm camera. Nobody wants those much now, so they are cheap unless it's a rare model. Take that suhutter apart, put it together, tinker with it. When you can handle that one easily, do the one on your large-format lens. The design will be very similar. -tony

Mine says 'Copyright 1999' in it. As I siad, I can;'t afford the manufacturer manuals for all the cameras I own or are interested in. So I have bought them for cameras I really care about, and will foolw my insticts on the rest. The 2 volumes of 'Cmaera Maintenance and Repair' have some designs for homebrew test isntrumewrns -- autocolimator, various exposure testers, etc. They can be infuriating for me, becuase I keep thinking 'I could do a better version of that' and never get round to it. Nor do I build the simple one form the book, which to be fair is probably good enough. Oh well... I know the feeling... One other thing that Tomosey says and which I entirely agree with is that uou must always do the best work you can, even on 'junk'. Do not get into the habit of saying 'Oh, this is worthless, I don't nbeed ot do the job properly'. You must not learn bad habits! I have never realyl botheresd with the Series-E lenses. Partly because I tend to avoid stuff build down to a price and partly becasue the lack the coupling form for non-AI meters. Yes, I know it can often be added, bnt.. -tony

It will be. There's almost nothing to builed, just an NPN phototrasistoe wired to 2 pins of the joyseick port (I think it's port B, but it's in the book). Then type in the program (it has some lines of DATA that are POKEd into memory, I assume a machien code program) , save it (!) and run it. THat's what I did. I read the first 4 Tomosey books (the non-brand-specific ones) and started workign o n'junk' cameras. I then read the 2 brand-specific books. But when I have an expensive, complex, cmera to work on, I try to get the mnufacturer's manual as well. Coincidence! I have a non-AI 135mm that I must have a go at converting. I have an AI one too, but when I saw the non-AI one for a really good price, I bought it to have a go at converting. Of course you can no logner get the conversion kit, so it's a matter ot attacking the aperture ring with an end mill...

On Thu, Oct 25, 2012 at 4:26 PM, <barythrin at gmail.com> wrote: It has 8 cores. 1 core runs basic (a tokenized basic). 1 core is assigned to emulating the SID chip. It even has filters. It was worth it just for that for me. Another core is emulating the video subsystem etc. The vga supports 64 colors, and that is done by resistor ladders. The propeller has a ton of pins, so that's not too hard. As Jeff put it: "Buying a PMC is a little like buying a snap together car model then discovering later it's actually an RC car. It's kind of our secret project that we know you'll discover it later and likely get hooked like us." I'll be adding another 32KB and the micro SD card reader this weekend. Fran?ois -- solarisdesktop.blogspot.com - raspberry-python.blogspot.com