On 9/4/07, woodelf <bfranchuk at jetnet.ab.ca> wrote: But aren't they simply front-end units to a central processor? I didn't think the 300 could do anything on it's own..

On 9/4/07, woodelf <bfranchuk at jetnet.ab.ca> wrote: Ah, but it's still a cool-looking, 40+ year old box with a keypad and a bunch of Nixie tubes :) So maybe I'll go for it anyway.

Jason T wrote: there is a tabletop box with nixies and keys and switches. There is a box, not a mainframe that was about the size of a desktop in the case of the ones at UMR that several heads were connected to. I believe that they had payed in the tens of thousands for a unit with 5 or so heads and a card reader for entering programs, in 1970 dollars. I have seen both the head and the processor and a working unit on ebay, but not very often. I have one of the card reader units, but nothing else. Jim

On Tuesday 04 September 2007 22:04, Fred Cisin wrote: Hollerith or those smaller ones that came along a bit later? :-) Been a long time since I've seen one of any variety, now that you mention it, though. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

On Wednesday 05 September 2007 00:23, Fred Cisin wrote: Aw, now see if you'd stuck "peecee" in there someplace I would've interpreted it that way... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

On 4 Sep 2007 at 22:23, jim wrote: There was a paper/mylar-based capacitive ROM used for high-speed applications on some 60's computers. Basically, you did the same thing--punched holes where you wanted 1's. Cheers, Chuck

On 5 Sep 2007 at 7:39, Lawrence Wilkinson wrote: There was a book in the 60's about user microprogramming various S/360 mainframes and their cousins. IIRC, the 360/30 was a great candidate because of the easily-created ROS. The Model 40 wasn't as good a candidate because it used magnetic technology (core of some kind?) ROS. The Spectra 70 was another great candidate for user microprogramming, but I don't recall the technology used for the microprogram memeory. The CDC Star-1B used "paper' ROS for its microcode. IIRC, crashes because of errors were very common. Cheers, Chuck

Jason T wrote: Rick Bensene wrote: ... I received two orphan 320K keyboard/display units a few years ago (no logic unit). Hobbled up a little level-shifting hardware and wrote some calculator code to drive them from a SWTPC 6800 - in other words the 6800 was replacing the missing logic unit. Worked fine but the next (intended) step was to redo it all in a microcontroller and stuff it inside the 320K case so it would be a stand-alone 'modern' nixie desktop calculator. Would be kinda nice because the 320K KDUs have a small footprint compared to other nixie desktop calcs. There is very little spare room in the case however. I think I anticipated it would be feasible if one used an external wal-wart (ugly) for the power transformer. The KDUs are very well built: cast aluminum case, micro-switches for the keys...

The keyboard/display units were simple -- WAY more simple than serial RS-232. Logic levels were not TTL (remember, these machines were made with all-transistor...no IC's anywhere either the keyboard/display units, nor the electronics package). RS-232 serial did exist back then, but IC UARTs didn't exist, and everything had to be implemented using transistor logic, which could fill a small drawer full of circuit boards alone. If you wanted to interface with one of the 300-Series keyboard/display units, you'd have to design some level shifters to make standard TTL (or whatever) levels. The interface to the display was a 4 bit digit select (selects which nixie tube is to light up), and a 4-bit BCD code for the number to light up in that nixie tube. Since the display was multiplexed, you just incremented the digit select, and sequentially presented the digits to be displayed on each tube. The timing was somewhat important, as Nixie tubes have some on/off duty-cycle timing issues, and the cycle rate has to be fast enough that the display looks continuous, but not too fast, or the digits won't be at full brightness. The keyboard was encoded by a diode array to a 6-bit code, and a signal indicating when a key has been pressed. There were also a few toggle switches on the keyboard that selected various operational modes which were just unconditioned switch closures. The keyboard switches were microswitches, which switch pretty cleanly, but still a little conditioning is needed to get reliable key entry (e.g., a bit of delay after the "key pressed" signal goes active before sampling the keycode). The keyboard/display unit has a cable that comes out of it that terminates in a telco-style (similar to old Centronics printer connectors, but with a different number of pins). Power for logic and Nixie drive (about +250V) was provided through the cable, as well as all of the other signals. I believe Brent Hilpert has derived schematics of the display, the keyboard, and pinout of the connector of one of the Model 320K keyboard/display units, which is has online on his website. Check out: http://www.cs.ubc.ca/~hilpert/eec/calctd/Wang320K/index.html By the way, early design 300-series calculator keyboard/display units had cast metal cabinets. Later, the design was changed to a heavy cast-plastic cabinet for cost savings. Rick Bensene The Old Calculator Museum http://oldcalculatormuseum.com

Me, for example. First, calculators are a lot more physically portable than "the spreadsheet app kept idling in the background" (which in my case is rather different, but I'm using it to refer to any kind of calculator facility on a computer). I have calculators in parts of the house where there is no computer handy. Second, the user interface is, at least in my experience of calculators and programs that can serve for similar purposes, substantially better-designed for the task. Part of this is the physical portability, but not all; a general-purpose keyboard is not the best input device for calculator functionality. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

On Sep 7, 2007, at 3:23 AM, Brent Hilpert wrote: I do. I use an HP-28S (for programming-related tasks) and an HP-41CV (for everything else) pretty much daily. -Dave -- Dave McGuire Port Charlotte, FL Farewell Ophelia, 9/22/1991 - 7/25/2007