Finishing up restoration of museum 1130, can install the virtual cartridge facility later at its home

FRUSTRATION THAT THE RESTORATION WAS SO DELAYED BY TOOLCHAIN ISSUES

The 1130 has been sitting idle for months now while I fought with toolchains to try to get my design to testing. I am confident that my logic for the design will be relatively easy to debug and get working,  as I have done this for Xerox Alto and Altair/Pertec disk drives quite successfully. 

The problems were with uusable Xilinx toolchain program under Windows 11 and then after a switch to Intel/Altera, with a maddening inability to create a working bootloader to get Linux to run on the board where my FPGA logic is already partly debugged. These were the issues that chewed up weeks and weeks. 

Originally I believed that the value to the owner of having the working Virtual 2315 Cartridge Facility was so high, making their machine far more useful to exhibit. Enough so that I focused solely on the new facility and left the machine sitting patiently in my workshop. 

However, I feel unhappy that it is not back in the hands of the owner already and increasingly frustrated that my problems with the bootloader and having such an impact on the restoration. Therefore, I resolved to instead get the 1130 ready to go back in full working order but prior to having the new facility.

WILL DEBUG THE VIRTUAL 2315 CARTRIDGE FACILITY ON MY OWN 1130

Since I have a working IBM 1130 of my own, I will also modify it to use the virtual cartridge facility, then do all the debugging on my own system until it is ready to install elsewhere. I will build more than one copy of the facility, so that it can be made available to other machines once it works here. 

INTENT IS, IF OWNERS WANT IT, TO FLY OUT AND FIELD INSTALL THE FACILITY

I have already installed the modification that allows the heads to remain safely above the disk surface while the drive believes it is working, so that installation of a fully debugged Virtual 2315 Cartridge Facility involves mounting a box, battery for data protection, interface logic board and installing some wire wrap to the drive electronics. 

I am happier doing this on site at its home rather than holding up the machine during the debugging. I can fly up with the parts and do the install and checkout locally. That assumes the owners want to pay for the boards, box, battery and other parts involved in the facility, since I am not charging any labor or markup. 

PARALLEL WORK, NOT GIVING UP BUT PRIORITIZING 1130 REMAINING TASK

The tasks remaining before the IBM 1130 system can be returned to its owner are:

1. Finish and install the new cover for the rear of the pedestal display panel
2. Finish testing console typewriter device controller logic
3. Finish repairing the 1053 console printer
4. Do partial testing of the built in disk drive controller logic

I have a design for a painted plexiglass cover for the rear of the display panel - I just need to bring my supplies to the local Makerspace and use their laser cutter, then finish up in the shop.

I had designed and built a substitute for the 1053 console printer which plugs into the IBM 1130 and will let me fully debug the controller electronics. It captures the solenoid activations and converts them to the proper typeball character, with accurate timing of the feedback signals to the 1130 electronics. This supports tabs, carrier returns, back and forward space, dual color ribbon selection and the front panel buttons that sit on the physical 1053 including tab set and clear. 

I should be able to run the full 1053 diagnostics and verify that the printout is what will be seen later when the physical typewriter is back in the machine.

The typewriter is still gummed up and the main shaft that the carrier slides left and right along is corroded and binding. If I can repair the existing shaft I will otherwise I will find a donor from another Selectric I typewriter of the same width. Then it is a matter of adjustments and testing to get this working as it should before remounting it atop the 1130. 

The disk drive has very precious heads, which I am worried about damaging by attempting to fly them on a disk pack. Even with the most careful cleaning and assessment of both heads and cartridge platters, there is the risk of a crash. 

Instead I intend to test as much as I can without the heads actually loading down on the disk surface. I will use the wiring and mechanical change I made for the Virtual 2315 Cartridge Facility. This will let the drive go to Ready status if there are no bad circuits inside the drive itself. With the drive Ready but safely leaving the heads well above the surface, I can check the Sector and Index marks, seek operation and other aspects of the drive electronics but of course won't be able to read any data. 

This means that I can check out a significant portion of the driver controller logic but not everything. The real solution for the drive is the facility that I will get working once I blast through the concrete wall obstacle of the bootloader generation. 

I may be able to view the waveforms being generated for a write to the disk, further vetting the state of the machine, but to successfully do a read I need to inject the bitstream from my FPGA. Unless I can think of some super clever solution that does not require the facility, which would let me test the remaining circuitry related to reading. There might be a tiny FPGA project that makes a fixed stream after seeing a sector mark, suitable to verify that the fixed stream is read properly by the 1130, for example.