Labor savin' devices

I've found that the easiest way to carry the Cosco (4.5' tall collapsed) is to bend down, reach my arm completely into the space between the rungs, and grab a rung with my hand. With a thick jacket on, I can rest it on my shoulder. Otherwise, I carry it with my bicep. Carrying it open is OK, too. I put a stabilizer on the top end of mine which keeps the end off the wall, making it easier to paint under it. Ditto needing hard-soled boots, but half the rungs on the Cosco have flat tops, so I try to stay on them. TIP: Don't stand on a ladder in suede moccasins to paint.
Reply to
Larry Jaques
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O.K. Depending on the model, it may have been one I worked on. For a while I was in the test equipment repair division. IIRC, that was about the time that Tek was moving from listing input capacitance in uuF to pF on the front of vertical plugins.
All kinds of custom test plugins from Tek, including one which had a mercury wetted reed relay driven by the 60 Hz input power (likely filament voltage) to provide very high risetime signals to test the mainframe's capability.
O.K. My programming languages (exclusive of the HP 9800 desktop calculator) were:
MC 6800 assembly/machine language Microsoft 8K Basic for the Altair 680b Various basics from SSB for the SWTP 6800 and 6809. MC 6808 assembly language Basic-09 (for OS-9 on the MC-6809) (Has separatedly compiled modules which can be shared by other programs -- Position independent and re-entrant.) And somewhat similar to Pascal. ISO Pascal for OS-9 C (for OS-9, then a number of flavors of Sun unix) HP's "Rocky Mountain Basic", which had a lot of FORTRAN-like features.) When you typed in a keyword, it automatically switched to "Function" type capitalization -- if you insisted on using a keyword as a variable you could force it to a different mix of upper and lower case -- as I discovered when porting a program to a newer version with more keywords. :-)

O.K. I liked C because of the ability to access things at almost machine-language level.
O.K. I would have called it "header includes" (after all, in C, the are ".h" files for headers).
O.K. Not on linux, but on Sun's Solaris 10, and OpenBSD, there is (for SPARC based systems)
====================================================================== NAME bpp - bi-directional parallel port driver
SYNOPSIS SUNW,bpp@slot,offset:bppn
DESCRIPTION The bpp driver provides a general-purpose bi-directional interface to parallel devices. It supports a variety of out- put (printer) and input (scanner) devices, using programm- able timing relationships between the various handshake sig- nals. ======================================================================
Beyond that -- you would need to write your own C library routines to take place of the built (or loaded) into the kernel drivers.
For the first unix box I had -- a "Cosmos CMS-16/UNX" (MC-68000 on Intel Multibus) I wound up writing a program to access an I/O device from a hamfest -- Nicad cells along the top edge, and a crystal oscillator and a bunch of counters which served as a clock/calendar, and I could use it to automatically set the clock when I booted the system. Before that I had to key the time in every time I booted.
To access it -- I needed to use a root only system call to map the memory of the board's registers into the program space, so I could access the registers. I also wrote a similar program which would copy the current date/time into the card, to set it *once* -- or after a DST change. (Oh yes, speaking of DST -- this was just after a change of the offsets of DST -- and a open-source library and database for those, so they can be changed at need. (It is still in unix/linux flavors.) I compiled that on the system, and used it in my own programs which needed to deal with the date and time. But many other programs used the original library -- and I did not have source to change them. Also, the OS had compiled in a PST/PDT constant. Since I did not have the source for the kernel, I had to learn how to find and change the constant to move it to the east coast. I named the machine "Owlsley", figuring that someone who made and used his own LSD would have a weaker linkage to his current location than most people. :-)
O.K. So -- the clock update would override the access to the parallel port registers?
Makes me think of GWBASIC (or the BASIC which came with early MS-DOS system) which was derived from the BASIC for the Altair disk 8800. (8" disk, hard sectored, IIRC). On the Altair, the system booted BASIC off the floppy, and then BASIC controlled read/write to the disk, for saving programs and data files.
It happened to bypass the drivers in MS-DOS, so a program written in it could create files with spaces in the file names. No way to rename or delete the files from the OS command line. The only way was to do it from within BASIC (not documented anywhere that I could find -- but I had to figure it out to get rid of a file left behind by someone running the typing tutor program.
Sort of like a unix system providing networked file systems to a lot of (mostly unix) systems, and one or two Macintoshes. The Mac user could name a file something like "data-04/23/80", where unix systems will not allow a '/' or a null in a filename. The only way to clean up the filesystem (so backups would not fail) was to unmount the file system, and then use emacs (super-editor) to edit the directory in the raw. Change the '/'s into '-'s and then I could delete them from the mounted filesystem. (Of course, now not a problem, because Mac's OS-X has a unix under the GUI, so the '/' in a filename is no longer allowed. :-)
:-)
Sigh!
Enjoy, DoN.
Reply to
DoN. Nichols
O.K. Depending on the model, it may have been one I worked on. For a while I was in the test equipment repair division. IIRC, that was about the time that Tek was moving from listing input capacitance in uuF to pF on the front of vertical plugins.
555555555555555555555555555 My 531A and 541 suffer high voltage arcing. What's an acceptable cleaning method and solvent? I realize they are good mainly for backup heat on chilly mornings, except that I have type W and 1L5 plugins. 555555555555555555555555555
555555555555555555555555555 The only job I did that needed the full speed of machine language was experimenting with an open-loop driver to step a drum printer head with critical damping, ie as fast as possible without overshoot. So I wrote it in 80286 Assembly. The non-contact position sensor was a small Radio Shack solar cell partly shaded by the head.
The printer port is hardware-limited to about 1 uS minimum pulse width, plenty fast for 100 KHz I2C data. 555555555555555555555555555
555555555555555555555555555 It's an interrupt that paused whatever my program was doing, such as counting a timing loop. I had to complete a time-critical task in less than 55mS and then poll the timer until it changed. I2C has a synchronous clock and isn't too fussy about timing, but the computers the program might run on could have CPU clocks anywhere between 50 MHz and ~1.5 GHz so I needed to measure the speed of timing loops and adjust them into a more reasonable range. 555555555555555555555555555
Sort of like a unix system providing networked file systems to a lot of (mostly unix) systems, and one or two Macintoshes. The Mac user could name a file something like "data-04/23/80", where unix systems will not allow a '/' or a null in a filename. The only way to clean up the filesystem (so backups would not fail) was to unmount the file system, and then use emacs (super-editor) to edit the directory in the raw. Change the '/'s into '-'s and then I could delete them from the mounted filesystem. (Of course, now not a problem, because Mac's OS-X has a unix under the GUI, so the '/' in a filename is no longer allowed. :-)
555555555555555555555555555 I've modified file structures without OS interference by passing the raw data through an HP1000 minicomputer running my assembly program. That's not the easy way but the boss liked to challenge me.
Mitre avoided PCs after the Cuckoo's Nest incident. We had Macs and SPARCs which were less well supported than PCs as CAD and lab machines. I had to design and build a 16-bit A/D data acquisition board for a Mac and write its LabVIEW driver. The Mac was a fine computer as long as you did what Apple knew you should, but our research needs went much further. I don't avoid them now out of ignorance. The $5 - $20 laptops I find at flea markets are retired business-class PCs like this D630, and I know how to upgrade and use them for what I want; HDTV recorders, data acquisition, SDR radio, etc.
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"SpeakEasy, the military software radio was formulated by Wayne Bonser, then of Rome Air Development Center (RADC), now Rome Labs; by Alan Margulies of MITRE Rome, NY;"
Rome Labs didn't have technicians who could build it (I was told) so SDR landed in my lab at MITRE Bedford, MA, as unlike the radio/radar techs I had considerable experience in A/D converters and computer hardware and circuit board design, and can solder tiny surface mount parts.
The concept of SDR receivers is old, the enabler was an A/D converter fast enough to digitize the IF frequency, not just the baseband. The fastest available went into digital oscilloscopes so they were what we used. A few years earlier it had been a struggle to obtain an A/D fast enough for an optical document scanner. The scanner processor was that same TMS320, for which I designed the DRAM controller, another see-if-he-can-do-it challenge.
The enabler for SDR transmitters is the Direct Digital Synthesizer. I was using Molybdenum-cased hybrid modules with hand-written single digit serial numbers. I milled an aluminum model of the DDS at home to avoid handling the static sensitive parts while figuring out how to fit them and an adequate heatsink into the narrow space of a VME slot.
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Jim Wilkins

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