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Author Topic: NTDS - Navy Tactical Data Systems  (Read 6627 times)

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Offline rhclinton

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Re: NTDS - Navy Tactical Data Systems
« Reply #2 on: April 01, 2016, 14:12:32 PM »
When I reported aboard the King in July 1963 there were already several DS's aboard - Martin Haley, Gerry Lolwing, Danny Garske are names I remember.  NTDS was still a novelty in the fleet:  King, Mahan and Oriskany were the only three ships that had it.  A few years ago I wrote up some recollections and posted them on the Data Systems Technician web site.  Here they are again:

The Politics of IDAC
 by rhclinton on Sat Dec 02, 2006 6:56 am
IDAC was one of the ugly stepsisters of NTDS. The initials stood for Interconnecting Digital/Analog Converter ? I can, after a lapse of nearly 50 years, no longer recall the AN/ designation of the device.

IDAC was intended to provide an interface between NTDS and the Terrier missile system on a DLG. Since NTDS was digital and the missile system computers were analog, the need for both digital-to-analog and analog-to-digital conversion arose. The device was manufactured by Univac. The digital logic used the same cards as were found in the CP-642 computers and the other peripherals and the documentation for it was in the familiar bubble diagram format. The D/A and A/D converters, however, had been subcontracted to another manufacturer and the documentation for them was far less useful. All of this was housed in a familiar two-bay Univac cabinet, with cooling blowers located in the bottom of each bay.

Although IDAC had been mentioned when I went through the first Systems course at Mare Island I did not actually encounter the machine until I reported aboard the USS King (DLG-10) in July 1963. Since I was assigned to the computer/peripheral gang, responsibility for it devolved to me ? I think DSC Gerry Lolwing and DS1 Martin Hailey were glad to get rid of it.

The CP-642 computers and the other Univac peripherals lived in the air-conditioned luxury of the computer room, but IDAC had been exiled to the DS shack which was not air conditioned and which had a door opening onto the weather deck. Internal cooling was not a problem because IDAC was cooled by the same chill water system that served the rest of the NTDS installation, but during our 1965 deployment to the Tonkin Gulf, disaster struck. The hot, humid air of the Gulf came in through the door and was sucked into IDAC?s cooling system which did an effective job of condensing the air and depositing the moisture in the air deflectors in the bottom of the cabinets. Since the blowers were designed to deflect the air upwards they also sprayed the water ? still containing salt ? over the logic cards in the left-hand lower drawer and over the converters in the right-hand one. The resulting corrosion was inevitable. We seldom had reason to open the lower drawers so this problem went undetected until we ran routine maintenance and found that the loopback test had failed. Repairing the logic circuits was just a matter of changing a few cards. Getting the A/D and D/A converters back in operation was more challenging but we managed it, though there were always a few residual problems. To prevent recurrence of the problem we throttled the flow of chill water into the cabinet and allowed the internal temperature to rise to the maximum allowable level, thus reducing the condensation.

Why have I included the word ?politics? in the title? Usually whenever there was the slightest glitch in NTDS ? problems with the computers, Link 11, even a single display console ? everyone from the Skipper on down were hovering around the DS gang, expecting an instant solution. But the attitude toward IDAC problems was surprisingly casual. I found this puzzling but it was not until only a couple of years ago that I discovered the explanation. This revelation came when I acquired a copy of When Computers Went to Sea: The Digitization of the United States Navy by David L. Boslaugh. There appears to have been a high degree of resistance among some officers to the introduction of NTDS, characterized by the assertion ?No damned computer is going to tell me how to run my ship.? Nowhere was this attitude stronger than in BUWEPS where the responsibility for the Terrier missile system resided. Although it was not at the time apparent to those of us at the maintenance level of NTDS, I can now see that the missile people were simply uninterested in receiving any target designation data from NTDS and were totally unconcerned about the health of IDAC. Later installations of NTDS would incorporate the Mark 11 Weapons Direction System and IDAC would fade into obscurity, but this was after my time at sea.

When the King returned from its 1965 Tonkin Gulf deployment I received orders to instructor duty at Mare Island. In January 1966 I said farewell to ship, shipmates and IDAC and drove up the coast of California to report to my new duty station. There I was greeted by a smiling Gerry Lolwing who informed me that my first assignment would be to teach ? you guessed it ? IDAC, for which a C-school had been developed. As I recall, I taught the course only twice as the supply of candidates was by then limited. Teaching the digital circuitry was actually a lot of fun, but we didn?t spend much time on the D/A and A/D converters.

Programming under Fire
 by rhclinton on Mon Feb 19, 2007 5:01 pm
Programming under Fire. I wonder how many times I heard that expression during my 30+ years in commercial IT. And each time I had to smile because I had really done it ? or nearly so.

Most of the time during the King?s 1965 Tonkin Gulf deployment life was pretty routine ? port-and-starboard watches, tracking outbound and inboard sorties and plenty of boredom. But a few times we went to General Quarters in anticipation of action that never occurred. On one such occasion the tension was quite high; there had been intelligence warning of a possible MIG attack. Condition 1 was set throughout the ship and in the computer room we did a fresh load of the condition 1 operational program. So everything was in readiness, or so I thought. I?m sure you recall how the NTDS Op program worked. The principle was for it to always move the ?hook? to a point just behind the radar sweep so that the radarmen were working with freshly-painted video. What constituted ?just behind? was a function of a parameter somewhere in the Op program which , as I recall, defined a sector of about 30 degrees. The radarmen had used this to good effect for several years but at this moment of high tension, the Operations Officer came into the computer room and requested that this sector be narrowed, probably to around 15 degrees.

Now, at this time in the history of NTDS, the philosophy was that all programming was done at the Fleet Computer Programming Centers (the one on the West Coast was at Point Loma). The only times we saw programmers ? officers and civilians ? was when the ship was about to call at a desirable liberty port such as Hong Kong. All the rest of the time the Op Program was expected to run without modification and there were no official programmers aboard. We enlisted DSs were trusted to maintain the hardware but the subtleties of programming were thought to be beyond our intellectual grasp, though there was about a week?s exposure to the Op Program in the Systems course at Mare Island. And the reality was that aboard ship we did a lot of digging into how it worked, using the listings stowed on board for the itinerant programmers.

I had never looked at the relevant area of the program before but after a few minutes with the listings I managed to locate the parameter. And after a few more minutes of octal arithmetic I had worked out the revised parameter. But how to put it into operation? Stopping the Op Program was out of the question under the Condition 1 circumstances. However the designers of NTDS had thoughtfully provided a device called the Systems Maintenance Panel or SMP. Among other functions it provided the ability to do an inspect-and-change of a running operational program. You could look at and change a half-word at a time. And where was this useful device located? In CIC of course, which was darkened and crowded just at the moment. Undeterred by these obstacles I went up to CIC with my modified parameter and a gray Navy flashlight. With great trepidation I started entering the change. It was only one word of data but I was unsure what would happen if I changed the first half-word before the second one. Would the system crash? I held my breath ? and it worked!. The hook started hugging the radar sweep more closely and I had my 15 minutes of fame.

The MIGs never came and we soon went back to our normal steaming condition. And I took away one of my life?s most valuable experiences. No matter how tense things got in the civilian pursuits of banking, retail, government, etc. nothing could match the tension of ? almost ? programming under fire.

A B-Link Mystery
 by rhclinton on Tue Dec 05, 2006 12:09 am
The original design for NTDS included three radio data links. The predominant one was the A-Link (a.k.a. Link 11). This was the long-range data link that used HF radio to exchange track information among NTDS ships, and even today I marvel at how well it worked. The other inter-NTDS link was the C-Link (Link 12), which was designed for shorter range communication using UHF radio. It didn?t work. In the 2 ? years I was on the King I am certain the C-Link terminal equipment was never even powered up. The third link was B-Link (Link 14) which was included because the system designers knew that initially there would be few NTDS ships and it would be necessary to send track information to ships that hadn?t received the blessing of digital computers. B-Link was just a stream of human-readable information that was fed to an adapter that turned it into 5-bit Baudot teletype code for transmission by HF radio. The adapter was connected to a Model 28 teletype console which was not essential to the transmission of the stream but which could monitor it.

The B-Link data stream was copied by teletype printers on the non-NTDS ships and converted to a traditional plot by radarmen using grease pencils on Plexiglas plotting boards. But because there was never complete confidence in the reliability of NTDS on the ships equipped with it, the B-Link stream was also copied by a local teleprinter in CSC and the track data was put onto plotting boards as a backup.

B-Link got constant use during the King?s 1965 deployment to the Tonkin Gulf because the system ran around the clock, there were always aircraft being tracked and we were mostly operating with ships that didn?t have NTDS. This operation was largely routine but there was one occasion when something quite extraordinary happened. In the midst of the stream of track information there suddenly appeared a message addressed to one of our DSs, inviting him to perform an anatomically improbable act.

Now this suggestion was nothing that would not have been heard several times a day on the mess deck but unfortunately in this instance the medium became the message. The Squadron Commodore happened to be in his flag plot and saw the message emblazoned on the yellow paper of the teletype printer, so the incident quickly escalated to an intensity almost as great as Operation Rolling Thunder itself.

Naturally the Skipper demanded an immediate investigation. It was obvious that the message could have been inserted at several different points. One was the Model 28 attached to the teletype adapter. But this was in a corner of the computer room to which access was difficult because my accustomed post was in a chair which blocked the way. At the time of the transmission I was sitting there, and though I was probably asleep I was sure that no one had gotten around me. It could have come from another teletype on the local loop or even from one of the other NTDS ships ? we were operating with the Mahan and Oriskany at the time. There was even the suggestion that it might have originated in the operational program itself, in which case it would have been the world?s first computer virus. However, as I later testified at the board of inquiry that was convened to find the culprit, this was unlikely. Or at least I thought so at the time.

Despite the board of inquiry, a lot of theorising and intense questioning of potential miscreants, no conclusion was ever reached. In the best Navy tradition of never letting the innocent go unpunished in the search for the guilty, warning letters were placed in the service records of two of the DS watch leaders ? a total illogicality since the insertion could not have been done on both their watches. But at least at least the cause of justice ? USN variety ? was served.

I wonder ? perhaps someone reading this after 51 years will have a pang of conscience and confess to the crime. I?m sure the statute of limitations has run its course.




Offline Chuck White

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NTDS - Navy Tactical Data Systems
« Reply #1 on: November 25, 2006, 00:03:48 AM »
On this day November 24, 2006, I found the USS King in Jim Sievers back yard.  The Computer History Museum in Mountain View, California has a display on NTDS.  click here http://www.uss-king.com/ntds.shtml
Chuck White 1963-1967
BT3, EB Division, USS King DLG-10
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