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A water-cooled update

Earlier we reported on Vikings' planned watercooling system for OpenPOWER. Vikings is now reporting their second revision, an improved lower-pressure mount, should be available for purchase from their store in two to four weeks. Unlike the IBM HSFs this is a low-pressure mounting mechanism which made it both less expensive and easier to engineer, and also means a custom cooler for the higher pressures won't be necessary. (Vikings notes a short screw is used "so that it shouldn't be possible to tighten it too much.") No MSRP yet and no preorders currently, but it will be sold as a full kit (fluid also available, or use your choice of appropriate fluids depending on the tubing) compatible with all existing Raptor systems or as just the cooler/mount for those with an existing external radiator. For you crazy people trying to cram an 18-core into a Blackbird this might be your ticket, but I'm interested myself to get rid of the fan bank in my POWER9 HTPC spooling up and down — after all, the best advantage of liquid cooling is the peace and quiet. More to come when kits are available.

Ubuntu 21.10 and 20.04.3

Ubuntu 21.10 "Impish Indri" is also out, upgrading to kernel 5.13, GNOME 40 (but presumably past the teething pains in Fedora 34 which required later patching) and gcc 11. This is the last interim release before the next Ubuntu LTS, scheduled for April 2022; the current LTS is updated to 20.04.3. As usual, new installs on OpenPOWER require installing Ubuntu Server first, and then converting to Desktop.

Tonight's game on OpenPOWER: Space Cadet Pinball

I've always loved pinball even though in league play I was always pretty much bang-up average. My first experience was with a Williams Pin-Bot at the local roller rink (I can't rollerskate either) and I was hooked. In Floodgap Orbiting HQ we have a Williams Star Trek: The Next Generation which I'm doing a long-playing LED upgrade on and a Stern Sopranos.

Computer pinball, however, has been a mixed bag, largely because of the simulation fidelity necessary for good play. Nowadays you have Pinball Arcade on mobile devices and Visual Pinball on Windows, but for years the physics never really exceeded what you got in Bill Budge's 1982 Pinball Construction Set and table features were even more limited. The mid 1990s introduced probably the first generation of computer pinball games that actually played vaguely like real pinball and some real pinball tables were even ported (I played a credible if low-res version of Bally's Eight Ball Deluxe on my Mac).

Of these, one of the best known was Maxis' Full Tilt Pinball in one of its tables' incarnation as 3D Pinball for Windows - Space Cadet, included first with Windows Plus! for Windows 95 and then with every version of Windows afterwards (including NT 4 and Windows 2000) through Windows XP inclusive. This version was a port of the original Space Cadet table written in cross-platform C and had a slightly different ruleset. I enjoyed this version on my father's AT&T Pentium 75; later I got Full Tilt Pinball for Mac, which was a dual-version disc with Windows.

Apparently I'm not the only one that liked it because the 3D Pinball version was eventually decompiled and rewritten. This redux not only plays authentically with the assets from the Windows Plus! version, but can use the higher-res versions with Full Tilt, though the ruleset is still from the Plus! game. It uses SDL and can scale to larger screen sizes and faster frame rates.

Compilation on Fedora 34 on this Talos II was straightforward. With development headers installed for SDL2 and SDL_mixer, grab the tree (do this from tip, not version 1.1), mkdir build, cd build, cmake .. and make. Copy the resources from the game — for Full Tilt this is pretty much CADET.DAT and the SOUND folder, but for the Plus! version copy everything in the same folder as PINBALL.EXE — into the build directory (if you're using the Full Tilt version as I did, you may need to loop-mount the disc to get the Windows XA session to show up) and start with ./SpaceCadetPinball.

For best results, under Options make sure Music is checked (you'll need something that plays MIDI files), under Options, Table Resolution make sure Use Maximum Resolution is checked (if you use the Full Tilt assets, you get 1024x768, and you can enlarge the window for sizes even larger), and under Options, Graphics make sure Uncapped UPS is checked so you get all the frames.

Good luck, Cadet.

OpenBSD 7.0

OpenBSD 7.0 is available, compatible with Raptor workstations in big-endian mode as well as "expected to be" with IBM PowerNV hardware generally. New powerpc64-specific improvements include MSI-X support, a fix for page faults under recursive locking, a bump in the maximum data size to 32GB, and support for the dynamic tracer. This is on top of better GPU support, additional driver and device support, updates to OpenSMTPD, LibreSSL and OpenSSH, and lots of new port packages. You can boot OpenBSD directly from Petitboot and install over the network; download mirrors are worldwide.

Firefox 93 on POWER

Firefox 93 is out, though because of inopportune scheduling at my workplace I haven't had much time to do much of anything other than $DAYJOB for the past week or so. (Cue Bill Lumbergh.) Chief amongst its features is AVIF image support (from the AV1 codec), additional PDF forms support, blocking HTTP downloads from HTTPS sites, new DOM/CSS/HTML support (including datetime-local), and most controversially Firefox Suggest, which I personally disabled since it gets in the way. I appreciate Mozilla trying to diversify its income streams, but I'd rather we could just donate directly to the browser's development rather than generally to Mozilla.

At any rate, a slight tweak was required to the LTO-PGO patch but otherwise the browser runs and functions normally using the same .mozconfigs from Firefox 90. Once I get through the next couple weeks hopefully I'll have more free time for JIT work, but you can still help.

DAWR YOLO even with DD2.3

Way back in Linux 5.2 was a "YOLO" mode for the DAWR register required for debugging with hardware watchpoints. This register functions properly on POWER8 but has an erratum on pre-DD2.3 POWER9 steppings (what Raptor sells as "v1") where the CPU will checkstop — invariably bringing the operating system to a screeching halt — if a watchpoint is set on cache-inhibited memory like device I/O. This is rare but catastrophic enough that the option to enable DAWR anyway is hidden behind a debugfs switch.

Now that I'm stressing out gdb a lot more working on the Firefox JIT, it turns out that even if you do upgrade your CPUs to DD2.3 (as I did for my dual-8 Talos II system, or what Raptor sells as "v2"), you don't automatically get access to the DAWR even on a fixed POWER9 (Fedora 34). Although you'll no longer be YOLOing it on such a system, still remember to echo Y > /sys/kernel/debug/powerpc/dawr_enable_dangerous as root and restart your debugger to pick up hardware watchpoint support.

Incidentally, I'm about two-thirds of the way through the wasm test cases. The MVP is little-endian POWER9 Baseline Interpreter and Wasm support, so we're getting closer and closer. You can help.