Schedule August 2008
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Saturday August 02 - failed demo, Techniques for increasing electronic reliability
Wed August 06 - general,
Wed August 13 - general, planned visit by Jim Ingram
Wed August 20 - general, Thurs August 21 - tape team Sat August 23 - 4th Saturday
Wed August 27 - general, Thurs August 28 - tape team
Saturday August 02; Good News - CHM tours; Bad News - 1401 Tour ReadinessAn e-mail friend, Charles OHearn, and his wife came to town. He had worked Nike systems and then commercial computers for many years so of course I had to show him CHM Saturday August 2nd :-)) --------- Good News - CHM tours --------- At 12:00 we took the Short Visible Storage Tour, which was just fine :-)) Very well done - Museum can be proud :-)) At 1:00 we watched the Babbage Demo, nice crowd - Judith Haemmerle lectured, she is good!! and John turned, one jam - We were informed how lucky we were to see a jam, while John cleared it ;-)) The museum, Doron Swade and Tim Robinson can be proud. http://www.ed-thelen.org/BabInstCHM/index.html#Visit We then went to see the PDP-1 demo - again smoooth ;-)) fun :-)) Folks were impressed with first person comments by the docents - --------- Bad News - 1401 Tour Readiness --------- Then I took my guests to see the 1401 - I fired up the 50 Hz converter and the DE system. Then I key punched a date card and two name cards, and tried to run the BIGPRINT deck. First try it got a read check after about 8 cards, tried again - maybe 5 cards tried again - maybe 13 cards. So I gave my friends the name cards as souvenirs and we left to talk for an hour or so at a table in the Chess Exhibit. I watched Stan have a seemingly similar situation several weeks ago. - with about 20 guests - The DE 1401 system still has "morning sickness", not much better than http://www.ed-thelen.org/1401Project/Sched2007February.html#26 The machine has to be energized for several hours before probably working properly - --------- Tirade --------- (stuff deleted) And in civilian life, morning sickness is an indication of unacceptable reliability - no face if nothing else. Your very automobile - if it backfires and smokes for the first 15 minutes - guess what - you get the mechanic to fix it. Maintenance to get reliable cold starts is not rocket science. Whole generations of military and civilian folks have figured how to do it. --Ed Thelen
Techniques for increasing electronic reliability - Added August 9, 2008
The following 5 pages (about 1.1 megabyte) is from IBM Field Engineering Maintenance Manual 1401 Data Processing System 225-6487-3 (re-sized from Paul Pierce's web site, Thank You - about 7 megabytes) that deal specifically with increasing the reliability of the IBM 1401 - the procedures are listed as Scheduled Maintenance. These procedures have yet been used on our 1401s.
PPierce-IBM-225-6487-3-MarginalChecking.pdf, Marginal Checking (MC) (1.1 megabyte file)
These techniques were also used by General Electric Computer Department field people (and folks in other companies and services) to minimize electronic logic failures. I claim we made (or could make) electronic logic failures about as low as IBM. (But non-IBM companies generally did not provide such easy to use tools.) If we had had good peripherals available, we would have given IBM a much better run for the money :-))
Wed August 6 - General
- Attendees: Ron Williams, Bob Erickson, Bill Flora, Stan Paddock, Allen Palmer, Joe Preston, Judith Haemmerle, Robert Garner
Report by Robert Garner - most of core memory repair section by Judith Haemmerle
- Ron Williams, Bill Flora and Stan Paddock got BigPrint running again on DE 1401. Bill Flora cleaned brushes and ran ripple test with no errors. Stan re-punched a new BigPrint and ran fine.
Stan Paddock and Joe Preston worked on the first CT 729. They found a tape data cable, cleaned it and installed it between the 729 and the CT 1401. The tape drive seems to have several corroded contacts causing problems.
They found a "slow" vacuum motor and swapped it from a spare drive
Stan the Mountanieer
Other current photos
Rosie Wacha, a UCSC PhD student and a summer intern at IBM Almaden Research, at Robert's invitation, visited this morning: punched cards for BigPrint, marveled at Ron's "powers of n" program printing on 1403 (asked for a card copy of program) and overall seemed to enjoy her visit.
Bob Erickson began to investigate why there's a problem in the CT 1406 extended memory. Thinks there may be a broken wire on bottom plane (nearly exactly the same problem we had on DE 1406, but X wire vs. Y wire.) Bob -- Say more??
Bob's not waving his hands in a magical incantation; he's positioning the .0071 wire, holding it in both hands and working it back and forth. Teasing up the broken wire Tinning one end of the broken wire. You can see smoke rising from the soldering iron. The new wire threaded through the frame - you can see it lying across the cores. It's a different color because of the insulation on the new wire.
- Robert Garner met with Karen Kroslowitz (Collection Move Coordinator) to go over the procedure for retaining 1401 units in the Allison-Akbay "Temporary Storage Holding" in Mountain View building as a buffer zone for the project vs. what can be moved to Milpitas warehouse. Discussed with the team over lunch what their preferences were. Decided to keep following units in temp buffer area:
With Judith Haemmerle, went thru remaining CT boxes and dispersed items to 1401 room or to warehouse. Most boxes have been emptied. (Thanks to Judith for managing our little depo of CT boxes over the past several months and organizing copying of ALDs and manuals! See helps to keeps us honest and moving forward.)
- 2 motor/clutch- restored DE 729's,
- 1 good/1 spare CT 729's,
- CT 088 spare collator,
- CT 1403 spare printer,
- CT 1406 spare memory, and large card rack.
Wed August 13 - general
- Present for the regular work session were: Ron Williams, Bob Erickson, Bill Flora, Frank King, Stan Paddock, Glenn Lea, Joe Preston, Judith Haemmerle, Ed Thelen, Robert Garner
Glenn Lea (left) is back from a trip to Alaska. He claims he hooked this fish, but you know fishermen ;-)) I have been trying to see if this image was "enhanced" with PhotoShop ;-)) In any case, it took these three guys (Glenn says) to bring this one that didn't get away up from 450 ft. Am I being too cynical? I grew up in Minnesota, and lying about fishing was regarded as a Constitutional Privilege !! Just like for politicians and used car salespeople.
Ron Williams (left) and Bob Erickson bug shooting the CT 1406. They suspect that a slipping probe induced this problem - like it slipped, and a power supply tripped.
Folks were arriving for the Jim Ingram discussion with Fran Underwood. Here is (left to right) Bill Worthington, Dick Weaver and Shel Jacobs. Shel used to fish for customers - I think he looks like a great fisherman too. Jim Ingram (left, manager of the 1401 project) arrived from San Francisco with Robert Garner.
Jim Ingram (left, manager of the 1401 project) talking with Ron Mak near the DE printer - which just ran a greeting BIGPRINT :-)) Totally unperturbed by the hubbub, Glenn Lea worked on a 729 tape drive problem. Here, the bellows switch that senses vacuum is available from the vacuum pump, seems non-functional. Maybe fishermen, with single minded purpose, are useful after all !!
This is the assembling group for Jim Ingram's interview, primarily by Robert Garner, with further questions and comments by Shel Jacobs, and by speaker phone by Fran Underwood (Texas) and Van Gardner (Georga). This is the view from the video recorder. About six more people came in just before and during the interview.
Wed August 20 - General
- Present were Ron Williams, Bob Erickson, Bill Flora, Frank King, Stan Paddock, Glenn Lea, Judith Haemmerle, Ed Thelen, Robert Garner. Bob Feretich and Stutzman, Jeff were there briefly in preparation for their planned Thursday activities.
- Frank King reported that Joe Preston was in the hospital - some sort of staph or strep infection in his blood!! Joe had updated Frank what was going on with the 729 tape drive Joe was working on (the bellows switch above). Joe reported that the infection had settled in his right shoulder.
- In response to voltage margin checking questions, we found the voltage margin controls in the CT 1401. (The DE 1401 uses a separate control box, and the margin power supply had been removed before we received the machine.)
- Speaking of voltage margin testing,
Bill Flora found this swollen capacitor in the Voltage Margin Power Supply, located under the card punch section of the 1402 The capacitor is used by the ferroresonant transformer.
- Ron Williams showed "the rest of us" the 1401 running its first program in many years - admitedly it was not very complicated -
- Mov characters in storage until word mark
- Unconditional Jump back to the Mov instruction,
But the above loop seems to be working correctly :-))
Matthais Goerner, on break from mathematics studies at Berkeley, is visiting at Stanford and came to help us. He e-mailed asking what he could help with in say 6 hours - and maybe prepare for in advance. CT spare card sort/merging seemed a good idea -
Sound simple enough for a math major? - right - except -
"We" took note of this - but what 'cha goin ta do???
Different "CR" type card had very different numbers of components - and seemed very different. Leave it to a math major to notice different component counts :-((
- Picky picky picky ;-))
Frank King (left) Matthais Goerner and Bill Flora examining "CR" cards.
I suppose when "we" find a defective "CR" card we will have to search for a replacement that at least has the same component count and looks the same - . Maybe best we didn't shoot the messenger ;-))
It appears that another wire in the CT1406 core stack has broken !! What is going on?? Here is a look at Bob Erickson's secret weapons for core stack soldering, micro (or is it nano ;-)) soldering tips.
- One of the things we had proposed for Matthais Goerner to consider was SMS card testing. Card testing is a non-trivial problem. (In a previous life I had received a job offer from General Radio to help develop a "bed of nails" card tester, and turned it down as being a tougher problem than I wanted to deal with - system software was "interesting" enough for me - and likely had a longer career path :-))
Our problem is now worse as Tim Coslet is now in Montana, along with his three point in-circuit testor. We currently have no effective way of fixing suspect/defective cards.
Here are three card test aids that have been constructed during the past years - their usage is *very* knowledge and labor intensive. The human must be very transistor and circuit savvy!!
The unit on the right can hold/test double wide cards, such as the STAR (STorage Address Register) cards.
Matthais suggested that maybe we design something which just looks for gross defects - open, short -
Ron Williams said that those problems are relatively easy to trouble shoot - the difficult trouble comes when say a transistor is leaking too much and causes a "base line drift". or a weak transistor barely able to drive the required load, or a slow transistor - border-line stuff -
(The various IBM specified margin tests (1.1 metabyte file) help turn border-line cases into solid error cases during the margins, making much easier trouble shooting - and help get borderline cards out of the system.)
To make reliable hardware capable of testing for the many variables is daunting -
To make a bad problem even worse, there seemed very little restraint on issueing new SMS card types. I did an analysis of card usage in the DE 1401 and 1406 which showed "The 1401 processor has about 2912 SMS cards of about 223 SMS card types, ... " To make a data base to effectively test the various circuits (including storage elements - flip-flops) for this number of unique cards seems doubly daunting. :-((
Not included are cards unique to 729 tape drives.
Frank King and Ron Williams publicly state that when a "repaired" card - or "no fault found" card came back from the repair center, and didn't work, that card usually had a fatal "accident" - like getting broken -. Others just nodded knowingly.
Thurs August 21 - tape teamFrom Bob Feretich
Jeff and I made plans to start working at the CHM on Thursdays again. We have two projects in mind.
- Demonstrate a Fortran-II Compile on the German system.
- Bring-up of the TAU on the Connecticut System.
The German System:
We would like to set up the Tape Drive Emulator for docent and class use. We thought it appropriate to accomplish this by enabling the system to perform some classic 1401 program that required the use of multiple tape drives. Once we get the Fortran compiler up, it should be easy for other multi-tape programs like Autocoder or Sort/Merge to run.
We would like to set up the emulator to communicate via Wi-Fi to the user's notebook computer. Do we need to get any CHM IT people involved to do this? Usually IT managers get upset when they are surprised by unauthorized networks operating in their buildings.
This project requires the assignment of an IP address to the emulator. Will the CHM IT department provide us with one, or should we get one on our own?
We also want to create a virtual tape library. The tape library would be accessible to any Emulator user. It would initially contain utility programs like:
Of course, we also would put the Fortran compiler into this library .
- Tape-to-printer -- to print data from PC files to the 1403 printer. Docents could print classic character graphic art from images in the tape library. The museum could even start a character graphic art collection.
- Tape-to-punch -- to punch data from PC files to the 1402 card punch. A good way to create card decks, but be aware that the 1402 does not print the contents of the card at the top like the keypunch does. To make this useful, someone will need to restore an Interpreter (like an IBM 557 or 548).
- Card-to-tape -- to read cards from the 1402 card reader and transfer the card contents into a PC file.
- Tape copy -- to transfer data between the user's PC and a real tape drive.
Is there anyone at the museum who is interested in expanding this library concept to include the demonstration programs, like BigPrint? We can show them how to add programs to and manage the library. Writing demo programs would be much easier. Executable files are created directly from the Rope cross-development tools. ASCII to/from BCD conversions for data files is already built into the Emulator.
The Connecticut System:
Once Ron and Bob put the 1406 back together, Jeff and I could start bringing up the TAU unit.
Which of the two projects should receive priority?
Robert Garner responded
I like your tape emulator proposals - thanks for taking this on! Being able to emulate up to 6 tape drives (while including our operational 729) will enable us to run the full complement of 1401 binaries we now have (before more of the 729's are running.)
Re: Which task is higher priority: Getting the CT 1401 TAU up and running with your Tape Emulator is highest priority.
Re: Your proposal for making available Fortran, Sort/merge, Autocoder, BigPrint, and a utility library via the Tape Emulator is fantastic! Of course, once the CT 1401 is up, your Tape Emulator can be used there too.
For the wireless network and IP address, contact Khanh Tran or Vinh Quach. (I've cc'd Vinh on this msg.)
p.s. Our recently acquired Fortran, Cobol, Autocoder, etc binaries that Paul Pierce read for us are located here: http://www.piercefuller.com/library/ibm1401.html
I can resend Paul's emails describing the formats, etc, if you don't still have them in your inbox.
Ed ---> Have we copied these images to our web site? Thx!
Sat August 23 - 4th Saturday
- Present were Ron Williams, Bob Erickson, Judith Haemmerle,
- All 16,000 characters of storage now work :-)) Accomplished today were:
- A broken wire near the previously soldered wire fixed (soldered). This may have been "collateral damage"?
- Two cold soldered joints fixed
- Two, maybe four? SMS cards in 1406 were bad -
- Bob and Judith were checking timing pulses in the 1406, Ron says that he was leaning back in the big easy chair, leading the good life.
- Team members now (3 PM) entertaining CHM guests :-))
Wed August 27 - generalThere was activity - I took vacation from web site
Thurs August 28 - tape teamFrom Bob Feretich
TAU Debug Status - Thursday, August 28th (Jeff & me)
We started working on the new 1401's TAU last Thursday. Our first objective was to fix the bugs that were preventing the TAU from reseting. (When reset, all indicator lights on the TAU control panel should be off. Two were on.)
The first thing that we noticed was that there were a lot of yellow wires on the TAU backplanes. This indicates that many engineering changes were applied to this machine while it was in the field. The second thing that we noticed is that _*the TAU logic in the vicinity of the first bug did not match the ALD documentation!!!*_
When we copied the TAU ALDs we found changes to about 6 pages. From the number of yellow wires, the changes are much greater than that. _*The TAU is at an engineering change level somewhere between its documentation and the German system.*_
We were able to use the German ALDs to trouble shoot the first bug. The Conn. systems ALDs were able to be used for the rest of the work Thursday. However, the documentation gap may could become a show-stopper down the road.
- The TAU now resets correctly. (We replaced two bad cards.)
- We verified that the TAU's control counters (Read. Write, & Delay) count correctly.
- We can't go much further without attaching something to the tape interface. We plan to attach the 729 Emulator to it next week.
- Then we will try to run some of the TAU I/O functions. (Rewind, read, write,...)
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