Thursday, November 9, 2017

Built PC side of the HPdrive disk emulator, watched Ken get the ethernet tool working well


HPdriver disk emulation facility setup

I picked up a Windows 10 based desktop system, this time with room to install my NI HPIB card. I did have to invest several hours activating and processing updates, plus managing a huge list of downloads automatically triggered by Microsoft. 

Once the system was up to date and ready, it was time to authorize use of test drivers, since the custom driver for the HPIB card does not have a Microsoft certificate ($$). I inserted the card and selected the custom driver, then did some testing. 

As far as I can tell without having it cabled up to the 12821A card in my HP 1000 system, it is working properly. It was listening through the PC card for requests from the minicomputer. 

repairing tape drives in 2645A terminal

I received my Plasti-dip shipment and packed it up to take over to Marc's home tomorrow where we can work on our tape drives (and other things). The concept is that I build up layers of this rubbery material on the capstan, then we turn it down to desired size.


Ken found a few timing vulnerabilities in his logic, plus a bug in the LCM's IFS software. The IFS software, when it encountered an error in a TCP transmission, waited expecting the Alto to resend the proper packet but it required a kind of ACK to be sent back to cause the Alto to restart. The timing issues he could address by a few changes to his code.

I watched as he tested it for a couple of hours, ensuring that the race conditions did not cause problems - basically the issues arose when Breath of Life packets were being transmitted from tool to Alto very close to when the Alto was sending a TCP packet. It was quite solid and just about ready to share with others who have Alto systems.

The benefit of this tool is that it hooks to an Alto without requiring an external ethernet adapter, any 3Mbit cabling or any other Alto system. It allows network booting for those whose disk drive is not working properly, as well as file sharing and other functions for regular disk-booted operation.

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