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Wednesday, November 20, 2013

Emulator Version 0.16 Released

Nigel and I are pleased to announce that version 0.16 of the retro-B5500 emulator has been released. All changes have been posted to the Subversion repository for our Google Code project GitHub project. The hosting site has also been updated with this release, and for those of you running your own web server, a zip file of the release can be downloaded from Google Drive.

This is a bug-fix release. Our community of enthusiasts found some rather serious problems in the new datacom interface, and some minor ones in the new magnetic tape drive interface. The most serious problem was that entering a zero-length message on the datacom terminal when would result in a "DCA ERROR ... READ BOUNCED BACK" error on the SPO, followed by a complete hang of datacom.

These problems have been fixed, and both new interfaces now appear to be working well. We have also made a few corrections and enhancements to the wiki pages.

We have also seen and had other reports of major instability when running the Timesharing MCP (TSMCP) and CANDE -- Invalid Address and Flag Bit faults, which typically result in either a program being DS-ed (aborted) by the MCP, or a complete system hang. Another report earlier today suggests that doing a fresh cold-start may resolve the problem, but this has not yet been confirmed. Obviously, we are concerned about this, and have not ruled out that it may be a problem in the emulator. Investigation is underway, but you may want to wait a bit before getting too excited about running TSMCP and CANDE.

In other news, Paul Cumberworth and Tim Sirianni are currently working on the set of card-load-select decks necessary to cold- and cool-start a B5500. Up to the present, we have had to rely on the ColdLoader script, a custom web page built for the emulator that initializes the IndexedDB disk subsystem, creates initial disk directory structures, and optionally loads files from Sid McHarg's B5500 Mark XIII tape image files. The card-load programs are the official way to do this type of system initialization, but could not be used until the card-load-select mechanism and support for tape drives became available. Once Paul and Tim have these decks working, we will make them available to everyone.

Finally, communication among the members of the retro-B5500 emulator community to date has been accomplished largely through email. As the number of interested parties has grown, this has become burdensome, so this week we created a web/email forum on Google Groups and linked it to this project. Membership is open to everyone. To join the group, go to
 The primary purpose of this group is to provide a vehicle for discussion, questions, answers, and support for those using the emulator, and for discussion on the Burroughs B5500 system and software in general. We hope you will join us.

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