Bendix G-15 Restoration

[stephenbuck]

Currently, I'm hitting some issues with the divide logic. The PPR is loading, but I need to code up a Flexowriter emulation to get the user interface up and running.

I would certainly be interested in a copy of the PPR spreadsheet! Can you post it to this thread?
Thanks,
Steve

 

[rbep]

Here's the "work-in-progress" Excel version of the PPR. The three buttons are to generate the binary, punch a block, or do a combined punch of all the contiguous sheets prefixed by a number track. It follows standard G15 practice of uvwxyz instead of abcedf hexidecimal. The arcane L numbers are filled in for the line31 opcodes if left blank. Jumps to vacant locations and code with no antecedent are flagged. I'm using it a lot to write test routines to debug my gate level simulation. The punched tapes load into the Kimpel emulator just fine. Let me know if there are any bugs to fix.

 

[rbep]

I would certainly be interested in a copy of the PPR spreadsheet! Can you post it to this thread?
Thanks,
Steve

I posted the spreadsheet. Seems to be awaiting moderator approval.

 

[stephenbuck]

An excellent new video in this series on a Bendix G-15 restoration!

Rotating Drum Memory with the Bendix G15

 

[stephenbuck]

And another one!

Removing the Rotating Drum Memory from the Bendix G15

 

[Thatguyagain]

Was there ever any luck in getting this G-15 into a museum or someone.

 

[djg]

Was there ever any luck in getting this G-15 into a museum or someone.

Its being restored for https://museum.syssrc.com/

 

[VERAULT]

I love His videos on the Centurion series, but I am completely facinated by these Bendix videos. They are great. There really isnt much out there on these old machines done in such an enjoyable format to watch.

 

[stephenbuck]

Its being restored for https://museum.syssrc.com/

The G-15 in the videos is being restored for https://museum.syssrc.com, as djg mentioned.

The G-15 in this thread is being restored for a local computer museum in Boulder, Colorado. Progress has been slow due to health problems, etc. Hope to pick it up again in the spring.

 

[stephenbuck]

Was there ever any luck in getting this G-15 into a museum or someone.

The G-15 in the videos is being restored for https://museum.syssrc.com, as djg mentioned.

The G-15 in this thread is being restored for a local computer museum in Boulder, Colorado. Progress has been slow due to health problems, etc. Hope to pick it up again in the spring.

 

[eightycc]

I've brought back to life an old project of mine, a SystemVerilog implementation of the Bendix G-15. The core G-15, that is the circuitry housed in the main cabinet including the CPU and I/O processor, are complete except for debugging. This portion of the project can be synthesized or simulated. It's relatively small, when synthesized occupying <25% of an Artix A15. Individual drum tracks are implemented as large (3132 bits for long tracks) shift registers.

For simulation purposes, I've implemented a SystemVerilog paper tape reader including relay control logic. Likewise, I've implemented a power-on sequencer that steps the core through start-up. So far I can read the first block of Paul Pierce's 'bxtst.pt' into M19, but find that the sign bit of every word in the track is set. I chased that for a day until I found that flip-flop OS never gets reset after the first 'minus' character on the tape. It turns out that G15 tapes must have a 'tab' or 'cr' character paired with each 'minus' character to reset flip=flop OS, but the 'bxtst.pt' tape contains no 'tab' or 'cr' characters.

So, I'm thinking that 'bxtst.pt' lost those characters somewhere along the line, possibly in the conversion process from physical paper tape. Today's project is to re-insert those characters as required producing a "fixed" 'bxtst.pt'.

 

[Kelly Gray]

You might want to check out Usagi Electric on Youtube. He's restoring a Bendix G15 to operational condition. He's almost ready to apply power to the system.

https://www.youtube.com/playlist?list=PLnw98JPyObn3QSIwUz5Iv6NA1x-uGFqAa