Tuesday, July 14, 2015

Checking out Pertec startup functionality plus achieved DOS/VS generation (but using Hercules)


I took my download distribution tape files over to a home PC where I had installed Hercules, and prepared to do my sysgen here instead of on the P390 (as the P390 won't support 2K pages which rules out ever running DOS/VS 34 on that machine).

Brought it up, IPLed the distribution tape and wrestled with Hetrcules for a while, until I could get it to IPL the tape and then read the virtual card file with my JCL. The distribution tape initialized the SYSRES disk volume and then restored the contents of the 'tape', using the default allocation for the four libraries (core image, relocatable, source and procedure).

It then was time to boot the new DOS pack and continue the sysgen. This was where I had hit the brick wall with the P390, but it all went swimmingly at this point. I used a default supervisor, modified the device configuration with ADD and DEL commands, then brought the system up. I formatted various first-time files and brought it all the way up to a normal running condition with Power doing the spooling.

The system is annoyingly fast - far far faster than on a real mainframe or on the P390. Restoring an entire tape to a 3350 volume took a couple of seconds, for example, and formatting all the power queues took mere seconds.

At this point, I have to work through the Sysgen manual and distribution tape cover letter to decide what supervisor and what other options I want on my system. This will involve running various jobs, assembling the new supervisor, and some other tailoring; for example, I will update the standard labels to match the way I expect my system to work. It won't be much work to prepare and then the actual execution will be almost faster than I can click the submission buttons, given the speed at which the simulated mainframe operates.


Power on testing with the two crowbar SCRs installed went fine. I then put the raw power supply back in the disk drive chassis, put the servo board back as well, and cabled everything up. I was quite careful to make sure everything was wired and buttoned up properly.

I took a bit of time to install cable ties to neaten up the wiring and keep things safely out of the way of both moving parts and swing-out sections for servicing. When I was certain that it was put together properly, it was time to apply power.

It came on, with the regulated power holding steady at appropriate voltages. When I pushed the disk start button, I heard the motor start to spin up. I cancelled that fast, since I am nowhere near ready to have the heads load.

The positioner is still sitting with the emergency unload relay inactive, and the solenoid isn't released to let me remove or insert a disk pack. The arm position detecting lamps were lit and plenty seemed good, but not with an unlocked solenoid. I may have a few more op amps or other parts that are bad, but it will be much easier to debug this now that it can hold power and let me monitor various logical states.

The 'safe' lamp is not illuminated when I power up, which is a necessary condition in order to release the lock solenoid. I need to fine the reason that the safe status is not achieved. I am surprised that the logic will spin up the drive if the safe lamp isn't lit, but it is doing so at this time. The lack of a 'safe' status is the first issue I will shoot.

Also, I see the emergency unload relay is not energized- whether that should happen at power on or only after the drive gets up to speed, that is the uncertainty. Still, I will check things around this to see if I spot any defective parts.


I still don't see any way that the connector pins I hooked to my SAC Box are related in any way to the fpga configuration signals. I am a bit wary of just hooking up the known good board, lest it too break due to some unforeseen interaction with my interface boards. However, I have to move forward at some point. The risk is destroying another $100 board if this problem stems from an own-goal, but I am about at the limit of what study can be done prior to live fire testing.

I am going to order the replacement board from ztex but with the stipulation that they have programmed the board with their 'light show" demo so that the board comes up running that code when powered on. That assures the power-on self configuration was working when they ship it out, and will be the first test I perform when I receive the unit. 

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