This is what I remember.
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That and Mystery Mansion.
Posted on 08/17/2016 10:29:43 AM PDT by zeugma
I was poking around some old data today from some old backups, and I ran across something the old time computer folks will recognize and thought I'd share.
Many, many moons ago, before the internet was much more than a few government systems set up to 'talk' to each other, we still had PCs and stuff, believe it or not. Granted, compared to the system you can buy for a few hundred dollars today from just about anywhere on the internet, they weren't much, but they were what we had.
There were also things called "magazines" printed on thinly sliced dead trees. These covered just about any topic you could imagine, so of course, there were some dedicated to computers.
In some of these periodicals, you'd sometimes have little programs printed that you could, if you were careful and didn't make any mistakes, enter into an editor on your computer, save, compile and execute. Some were so tiny that if you were using a computer that used the DOS operating system, you could enter into a program called "debug", and almost immediately execute them. Debug was a really powerful and dangerous program, because it would give those who invoked it direct access to just about any scrap of memory or disk on your computer. Used injudiciously, you could easily trash your hard disk, or worse.
Because DOS didn't really have much intelligence to it, it was difficult to write interactive scripts. So, over time I put together a collection of tiny utilities to make my batch files smarter. One such program would read what key you entered, and output the scan code of the key as an error code. So, you could have your batch file prompt for input, then take different actions depending upon what the user entered.
here's the code for "key.com".
N KEY.COM E 0100 B4 00 CD 16 EB 0E 77 06 3C 60 76 02 E 010C 24 DF 3C 00 75 02 88 E0 B4 4C CD 21 RCX 0018 W Q
If you entered the above into a plain text file, and saved it as KEY.SCR, then enter the following from a DOS prompt:
DEBUG < KEY.SCR
you would end up with a program called KEY.COM that would interpret and echo keystrokes to help your batch files a little smarter than they otherwise would be.
The program, KEY.COM is tiny, weighing in at a whopping 24 bytes. However, it's diminutive size did not adversely affect it's utility. An even smaller pair of programs were something I called "WARM.COM" and "COLD.COM". They would reboot your PC immediately. 'Warm.com' was the equivalent of pressing the [ctrl]-[alt]-[delete] key, which would reboot without performing a full POST (Power On Self-Test). 'Cold.com', on the other hand, was like powering your computer off and back on.
If you were to run the following through DEBUG as shown above, you'd create both programs.
N WARM.COM E 0100 B8 40 00 8E C0 26 C7 06 E 0108 72 00 34 12 EA 00 00 FF E 0110 FF RCX 0011 W N COLD.COM E 0100 B8 40 00 8E C0 26 C7 06 E 0108 72 00 00 00 EA 00 00 FF E 0110 FF RCX 0011 W Q
It is easy to spot the difference between the two programs. The bottom line, was that the program told your computer to jump to a certain memory location. The different locations controlled the different boot types.
One final debug script I'd like to mention is 'BEEP.COM'. It wasn't the most powerful program in the world, as it had one simple job to do. It would make your computer speaker beep once. That's it. What is cool about it (to me any way) was that the entire executable was a whopping 6 bytes! To this day, I've never seen a smaller functional program. Here it is, in all it's awesome and tiny glory:
N BEEP.COM E 0100 B8 07 0E CD 10 C3 RCX 0006 W Q
The dates associated with the files indicates how long ago I was talking about...
-rw-r--r-- 1 zeugma zeugma 6 Jan 28 1994 BEEP.COM -rw-r--r-- 1 zeugma zeugma 56 Mar 11 1995 BEEP.SCR -rw-r--r-- 1 zeugma zeugma 17 Dec 22 1991 COLD.COM -rw-r--r-- 1 zeugma zeugma 94 Feb 13 1996 COLD.SCR -rw-r--r-- 1 zeugma zeugma 24 Dec 6 1992 KEY.COM -rw-r--r-- 1 zeugma zeugma 17 Dec 22 1991 WARM.COM -rw-r--r-- 1 zeugma zeugma 94 Feb 13 1996 WARM.SCR
If it works, why change it?............B^)
No, not exactly. What it means is essentially no intermodulation product produced.
In cell and PCS worlds the key to keeping interference from degrading individual channels from causing problems on others via intermodulation products, the capacity for the entire ‘circuit’ to produce intermods is measured. Thus the -153 dBc....decibels below carrier...start with at least two 10 watt in-band tones and measure all INBAND (3rd order) intermod products that fall within the desired band. Too high products and you get interference. A very important measure of performance especially with equipment and tiers on a cell tower.
It was. 95% of a modern computer's power is wasted on flashy graphics. (yeah, I picked that number out of the air) No matter how fast your computer is, it never really seems to get any faster because the GUIs eat every available cycle. I'd love to run fractint on modern bare hardware. Some day I'm going to build a spare PC just to run Fractint on freeDOS.
I remember playing it on PDP minis. On a teletype printer that would print the star-map before I could enter the next move, no display monitor. Used a lot of paper playing that game. I still have punched paper rolls from programs I wrote for those PDP machines. But yeah, Star Trek was awesome!
Understood, but they later came up with TACANs and GPS....
This is what I remember.
.
That and Mystery Mansion.
No, not exactly. What it means is essentially no intermodulation product produced.
In cell and PCS worlds the key to keeping interference from degrading individual channels from causing problems on others via intermodulation products, the capacity for the entire ‘circuit’ to produce intermods is measured. Thus the -153 dBc....decibels below carrier...start with at least two 10 watt in-band tones and measure all INBAND (3rd order) intermod products that fall within the desired band. Too high products and you get interference. A very important measure of performance especially with equipment and tiers on a cell tower.
I’m working TACAN right this minute.
A calibrator for TACAN/IFF and SLS for the USAF..........
I remember something like 900 Hz rotation...is that still correct?
Don’t work with cell freqs. My expertise is in receiving HF systems and antenna distribution networks.
To me a 3rd order intermod (OPIP)is great if it’s above 80!..........
Looks to me as if both jump to FFFF:0.
What am I missing?
ML/NJ
I understand, but you have to realize exactly how much dropped calls and interference means to the cell industry. We are talking near a trillion a year in call costs and revenue. These effers are serious about it.
I once got paid an assload to go to their number one cell site at about 3AM to help them take down and test some new antennas. It was in Reston, VA, BTW.
They had three crane crews there to catch each side of the triad tier and install the new antennas. Also had a host of mobile crews cruising the ‘cell’ to gauge performance. It was a screaming expensive operation. Finished by 4 AM and back on the air making a buttload of money.
900 Hz rotation? I don’t know what that is.
My TACAN system uses gaussian pulses of various rep rates and spacings on an RF carrier of between 960 and 1215 MHz.
IFF IS 1030/1090 MHz rectangular pulses of various widths and spacings.
SLS uses 1030/1090 MHz with rectangular pulses of varying amplitudes, spacings and widths relative to each other.
The TACANS of my day I seem to remember as linear antenna line radiators on a rotating cylinder. I’m probably wrong and I could very well be just full of sh!t... Navaids wasn’t my specialty. I’m just a dumb ass country boy my wife tells me. :0)
lol...yah I used xtree for a while too...this thread is really dredging up memories for me.
https://en.wikipedia.org/wiki/Tactical_air_navigation_system
http://www.rfwireless-world.com/Terminology/difference-between-DME-and-TACAN.html
Okay...just an old fart here. Pay me no nevermind.
The Ford EEC or Electronic Engine Control is a series of ECU (or Engine Control Unit) that was designed and built by Ford Motor Company. They were introduced in 1978 and went through several model iterations.
Contents
EEC I and II Edit
These two “modules” used a common processor and memory so they can be described together. The processor was a 12 bit unit manufactured by Toshiba. The Ford internal code name for it was “PM-11” or “Poor Man’s 11” implying it was a stripped down version of the, then popular, Digital Equipment Corporation PDP-11 computer. A PDP-11 was used in a vehicle in the first half of the 1970s for “proof of concept”. In reality there was very little in common between these two computer architectures. This chip was never commercially available.
A VOR ground station sends out an omnidirectional master signal, and a highly directional second signal is propagated by a phased antenna array and rotates clockwise in space 30 times a second. This signal is timed so that its phase (compared to the master) varies as the secondary signal rotates, and this phase difference is the same as the angular direction of the ‘spinning’ signal, (so that when the signal is being sent 90 degrees clockwise from north, the signal is 90 degrees out of phase with the master). By comparing the phase of the secondary signal with the master, the angle (bearing) to the aircraft from the station can be determined. This line of position is called the “radial” from the VOR. The intersection of radials from two different VOR stations can be used to fix the position of the aircraft, as in earlier radio direction finding (RDF) systems.
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