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Linux 5.19


Linux 5.19 is released, largely with more hardware support and new architectures (including an unusual super-modern virtual Motorola 68000 platform to emulate Google Goldfish devices — my real Q800, clockchipped running A/UX, is flabbergasted). Here's a full list of changes.

This release doesn't have a great deal of Power ISA-specific improvements, but one generally positive note can be implied from Linus Torvalds' announcement message: he's now on an Apple silicon laptop, running Asahi Linux. Recall that Asahi Linux uses 16K pages as opposed to 4K pages, and this is still the case; many Power ISA workstation users are on systems that use 64K pages, including this Raptor Talos II running Fedora 36. If software bustage is happening for Linus himself, then it's a good sign that more software will start becoming more flexible about allowing larger memory pages and that's good news for us niche configurations too.

Arctic Tern available for purchase


Raptor now has Arctic Terns available for purchase, along with the user's guide. The US$1600 bundle comes with the PCIe carrier card, one ECP5 FPGA module (using Microwatt, the FPGA OpenPOWER core), FSI and JTAG adaptors and all the necessary cabling to connect to a Talos II system (we presume this means the entire T2 family including the T2 Lite and Blackbird, but it doesn't say — more about that in a moment UPDATE: it does now). As it is designed to completely replace the onboard ASPEED BMC, there are fan, Ethernet and two (!) HDMI connectors on board. There is a second module slot as we surmised, but it appears most board functions will be available with just one FPGA module installed, as provided in this bundle (fortunate since an extra module is US$900).

Unfortunately it looks like it does need its own PCIe slot and people like me with a nearly full loadout will be a bit disappointed if that's truly the case. We don't yet know, because the user's guide doesn't look like it has installation instructions for any T2 family system either even though it does have Raptor's usual studious pinouts and schematics. Being primarily a peripheral, I look forward to seeing additional documentation posted since no one wants to buy a $1600 card, get it home and accidentally brick it and their expensive OpenPOWER computer. Once I get my hands on one, we'll talk more about it.

Tonight's game on OpenPOWER: Duke Nukem II


No, not that Duke Nukem game — I mean the platformer. Before the Build engine wrought PG-13 destruction upon the City of the Angels, which also builds and runs on OpenPOWER, Apogee introduced the world's most egotistical alien exterminator in two episodes of heavily armed hopping around. The first installment in 1991 was poor even among PC games of the time, especially considering the far superior (and also Apogee-published) Commander Keen that came out the year before. But the second episode in 1993 had better graphics, better animation, better music, even a rip-roaring VGA cinematic if you had the hardware:
(Always wear your eyes and ears during target practice, kids!) It generally plays fine in DOSBox, but where's the fun in that? RigelEngine is a re-creation of DN2 that plays like the original DOS game mostly faithfully — pedantic quibbles shortly — along with various enhancements such as widescreen support, shown here in the screenshot.

RigelEngine builds out of the box on Fedora 35 and 36, though it has a rather surprising amount of vendored 3rd-party libraries and additionally requires OpenGL, SDL and SDL_mixer. Make sure to clone it with submodules enabled (e.g., git clone --recursive), then mkdir build ; cd build ; cmake .. ; make.

You'll also need a copy of the game, either the shareware first episode (1MB ZIP) or the full game (which I have, as an early DN3D purchaser). Apogee-3D Realms titles have moved from GOG, our usual drug dealer, to ZOOM Platform. Put the NUKEM2.* files into a directory and point the RigelEngine binary at it, or it will present a basic file picker when you start and then remember those settings.

As a clean room re-creation of the game, the additional features are simply incorporated into the game's regular settings menu (i.e., no specific command line options are used to enable them). Widescreen works just dandy with the exception of the radar and inventory frames which can sometimes blend in with the display a little too well; otherwise, I highly recommend it. On the other hand, the smooth scrolling feature — while being as smooth as advertised — makes playing the game feel a little like I've been stoned, uh, not that I would know anything about that, offisher (too used to those rapid 8-pixel and 4-pixel parallax moves). Also, while I'm being an ungrateful whiner, the introductory VGA cinematic is also not quite right compared to DN2 on my real Am5x86/133 DOS tower: there's an extra pause in the transition between "NEO LA: THE FUTURE" and Duke in the shooting range, and his firing rate in the first scene is too quick (it's fine when you're looking at the target). I know, I know, right? Uncanny valley!

Note that RigelEngine doesn't play the original Duke Nukem (this does), nor Cosmo's Adventure, which uses code descended but different from DN2 (this does).

This is too easy!

Raptor says the Blackbird crunch ends in August (and maybe Arctic Terns too)


Good news for everyone with a Blackbird backorder: Raptor is announcing order fulfillment and restocking by August 31, 2022. This may not mean the order you submit now will get fulfilled by then, but if you have your order already in, the wait will be over soon and new orders should be processed much more quickly. (This date does not apply yet to the Talos II Lite, but I'm sure Raptor is working on it.) In the meantime, if you can't wait, may we suggest a regular T2? Those are in stock and ready for purchase.

Raptor is also stating Arctic Tern will launch in the "next few weeks" for purchase, with the Kestrel soft-BMC onboard and compatible with the entire Raptor family including the full T2 and the 'Bird. We're looking forward to it and expect a review as soon as I can get my hands on a couple. Faster BMC booting is always welcome around here!

Rocky Linux 9.0


With new version 9.0 Rocky Linux joins the list of ppc64le-compatible CentOS clones, along with the already extant AlmaLinux 9 and Circle Linux based on Red Hat Enterprise Linux 9 (itself based on Fedora 34). Rocky Linux explicitly requires a POWER9 CPU. Other than that, the big difference is the branding and the governance, but more choice is always good. Download ISOs are available.

CXL is going to eat OMI's lunch


The question is whether that's a bad thing. And as it stands right now, maybe it's not.

High I/O throughput has historically been the shiny IBM dangled to keep people in the Power fold, and was a featured part of the POWER9 roadmap even though those parts never emerged. IBM's solution to the memory throughput problem was the Centaur buffer used in POWER8 and scale-up Cumulus POWER9 systems (as opposed to our scale-out Nimbus POWER9s, which use conventional DDR4 RAM and an on-chip controller), and then for Power10 the Open Memory Interface, or OMI, a subset of OpenCAPI. In these systems, the memory controller-buffer accepts high-level commands from the CPU(s), abstracting away the details of where the underlying physical memory actually is and reordering, fusing or splitting those requests as required. Notoriously, OMI has an on-board controller, and its firmware isn't open-source.

But why should the interconnect be special-purpose? Compute Express Link (CXL) defines three classes of protocol: CXL.io, an enhanced CPU-to-device interconnect based on PCIe 5.0 with enhancements; CXL.cache, allowing peripheral devices to coherently access CPU memory; and CXL.mem, an interface for low-latency access to both volatile and non-volatile memory. Both CXL.cache and CXL.mem are closely related and themselves transmit over a standard PCIe 5.0 PHY. Memory would be an instance of a CXL Type 3 device, implementing both the CXL.io and CXL.mem specifications (Type 1 devices implement CXL.io and CXL.cache, and rely on access to CPU memory; Type 2 devices implement all three protocols, such as GPUs or other types of accelerators). The memory topology is highly flexible. If this sounds familiar, you might be thinking of Gen-Z, which aimed for an open royalty-free "memory semantic" protocol; Gen-Z started the merge into the CXL Consortium, led by Intel, in January.

IBM was part of Gen-Z, but eventually let it dangle for OpenCAPI and OMI, and while it is a contributing member to CXL this seems to have been as a consequence of its earlier involvement with Gen-Z. But really, what's OMI's practical future anyway? So far we've seen exactly one chipset implementation from one vendor and that implementation has directly harmed Power10's wider adoption apart from IBM's own hardware. OMI promises 25Gbps per lane at a 5ns latency, but Samsung's new CXL memory module puts 512GB of DDR5 RAM on the bus at nearly 32Gbps. It's a cinch that Power11, whenever it gets on the roadmap, would support at least PCIe 5.0 or whatever it is by then and CXL would appear to be a better overlay on that baseline. Devices of all sorts could share a huge memory pool, even GPUs. Plus, a lot more companies are on board and that would mean a lot more choices and greater staying power, plus more likelihood of open driver support the more devices emerge.

There are still some aspects of CXL that aren't clear. Although it's advertised as an open industry standard, there's nothing saying it's royalty or patent-free (Gen-Z explicitly was, or at least the former), and the download for the specification has an access agreement. The open aspect may not be much better either: Samsung has an ASIC controller in their memory device but it still may need a blob to drive it, either internally or as part of CPU firmware (earlier prototypes used an FPGA), and nothing says that another manufacturer might not require it either.

Still, OMI has the growing stench of death around it, and it never got the ecosystem support IBM was hoping for; CXL currently looks like everything technologically OMI was to be and more, and at least so far not substantially worse from a policy perspective. Other than as a sop to their legacy customers, one may easily conclude there's no technological nor practical reason to keep OMI in future IBM processors. With nothing likely changing on the horizon for Power10's firmware, that may be cautiously good news for us for a future Power11 option.