Monday, May 28, 2018

A weekend on the new computer (or, introducing "TenNineFox")

This Memorial Day weekend I pulled the Sonnet FireWire card from my Quad G5 and put it to sleep. I mean, I put it in sleep mode, and sat down with the Talos II to see if I could get Firefox building and running, and then QEMU (and to see if the G5 would stay asleep for more than a few hours, since I don't need a hot and noisy 230+ watt computer running next to my less hot but noisier 180W one). One glitch with this was switching the KVM away from the G5 caused it to wake up again, so I wrote a little Perl script to fork and log me out, and in the child process run a trivial AppleScript to tell application "Finder" to sleep. Then I could just run that from a remote login session from the T2, and the G5 would peacefully rest at about 20 watts or so.

First was to grab all the updates. This fixed amdgpu for X11 and now I'm running a fully accelerated GNOME desktop on the AMD Radeon Pro WX 7100. I got Sabrent Bluetooth and USB audio dongles, which "just worked" with Linux, and even got VLC to play some Blu-ray movies (as well as VLC can play them, given that BD+ is still not a solved problem). The T2 firmware update to 1.04 also diminished some of the fan hunting I was hearing and while it's still louder than the G5, it's definitely getting better and better. I'm thinking of getting one of the Supermicro "superquiet" PSUs next, since I notice its higher-pitch fan sound more than the case fans. The only hardware glitch still left over is that I can't figure out why Linux won't recognize the Sonnet FireWire/USB PCIe combo card. It should work, the chipsets should be supported. More on that later.

Next was to get working on builds. After most of Saturday spent hacking on it, I'm pleased to note that Firefox 60 will compile on the T2 with a minimal .mozconfig if you apply this patch, this patch and this patch, and chmod -x /usr/bin/ld.gold because the Firefox build system insists, nay, demands to use the (useless on PowerPC) gold linker; I don't even know why Fedora bothers installing it. You also need to turn jemalloc off because it barfs on the default PPC64 page size of 64K. The official Fedora 28 build of Firefox 60, which actually does work, apparently cheats a little by disabling tests and WebRTC, part of what those patches address, though I'm uncertain how they got around the jemalloc or WASM signal handlers issue. It runs fully multiprocess and I'm looking at enabling WebGL next. Even though JavaScript in Firefox 60 on the T2 is about twice as slow as the G5 in TenFourFox FPR7 (remember, no JIT), everything else is tremendously faster due to the 32 threads (8 cores, SMT-4 each), the monstrous cache and the 3+ GHz clock speed, so you really only notice it's not quite as fast as it ought to be on pages with a lot of scripts. So imagine what it will be like when I get the POWER9 JIT, I mean, nothing! I said nothing! Pay no attention to the man behind the curtain! If you build Firefox with -O3 -mcpu=power9, you get about a 3-5% speed boost over the -O2 mcpu=power8 Fedora build, which is worth it because it only takes the Talos 20 minutes to build Firefox at -j24 (compared to 3.5 hours with the Quad G5 in Highest performance mode roaring away at -j3). For posterity, here is the .mozconfig I'm currently using, which I intend to refine further:

mk_add_options MOZ_MAKE_FLAGS="-j24"
ac_add_options --enable-application=browser
ac_add_options --enable-optimize="-O3 -mcpu=power9"
ac_add_options --disable-jemalloc

You may call this the first build of "TenNineFox" if you like. :) Some mochitests fail which I'm investigating, but the test suite can run. By the way, Firefox Containers is awesome. I like to segregate my higher-security items like billpay and banking from the browser, which I use a TenFourFoxBox for on the G5, but with a Container it's integrated into the same browser instance and still keeps the cookies and data separate. Cool stuff.

On to QEMU. QEMU will build relatively uneventfully from source, or you can pre-install the Fedora package if you're lazy. Using the generic Power Mac profile mac99 both MacOS 9.1 and 10.4 start up largely happily under qemu-system-ppc, though there is an odd glitch with 9.1 where I have to quadruple-click on anything to get it detected as a double-click. However, while it was certainly useable, it didn't feel very fast. The System Profiler within the emulated Tiger instance said it was a "1GHz G4" with a "400MHz FSB." This seemed low, and the reason it is was ... drumroll please ... it was running with CPU emulation.

After some checking, I confirmed KVM was indeed installed on this system, so I tried running a 64-bit guest with qemu-system-ppc64 emulating an IBM pSeries machine with KVM-HV. That started up and ran at a nice clip, noticeably faster when I turned on KVM, so I tried to run the 32-bit guest with KVM-PR (which ought to emulate the proper CPU) and got an error message. Even the 64-bit guest that ran just dandy with KVM-HV wouldn't run with KVM-PR. Some digging determined that the KVM-PR kernel module existed, but did not load. Some more digging turned up that KVM-PR wouldn't load with modprobe. Even more digging turned up that ... KVM-PR doesn't run on bare-metal POWER9 yet, and unfortunately all PowerNV machines like the T2 are bare-metal.

This is a bummer, but it sounds like an eventually solveable problem. In the meantime, QEMU's performance as a Power Mac emulator is currently acceptable on the T2, just unspectacular. I'll be setting up an install of OS 9 to start with and getting some of my old software loaded into a workspace, and possibly hacking QEMU to autorelease the mouse and switch workspaces with a key combination so I can just jump back and forth easily. When the issues with KVM-PR are ironed out, then everything should "just work," just faster.

For yuks, I tried installing a couple earlier emulation efforts. SheepShaver is the one most people know, and it will compile (if you update config.{guess,sub} and tell configure to use the PowerPC emulator; it will not run natively), but it will not start. Even with sudo sysctl vm.mmap_min_addr=0 and sudo setsebool -P mmap_low_allowed 1 to get the kernel and SELinux to allow its unusual memory mapping requirements, it threw an error message saying it could not allocate enough memory and unceremoniously aborted. On a 32GB system trying to emulate a 256MB Mac a low-memory state seemed unlikely, so I'm guessing this may be a 64-bit bug. I then tried the other well-known Power Mac emulator, PearPC. This also required a new autoconf and a number of hacks to get it to build with current releases of gcc, but it does work, and it does start, and it's even worse, about 20% the speed of QEMU. The reason for this is that QEMU actually has a trivial JIT (TCG), while PearPC is a strict interpreter on systems that don't have JIT support, so while you could do stuff it felt like a 601 was running it instead.

The other parts of the weekend was figuring out what I needed to port over, and how to make the Talos happy on my highly Mac-centric network. Installing gvfs-afp and hfsplus-tools was easy and got the T2 talking to the G4 file server running 10.4.11. I don't like the Linux font set much, so I'll be copying my font folder from the G5 over and converting things with Fondu as necessary. VLC will play CDs, but I will probably try to port my command-line player since it's easier for me to manipulate. I also need to move my Quake PAKs and Doom WADs over, because everyone needs a coffee break now and then, and finally get my Pixel XL to backup its photos to it. I also added even more Mac key combinations to AutoKey to maintain my Mac command-key muscle memory.

Anyway, after I've submitted this post I'll power down the Talos tonight and wake the G5 back up again tomorrow to continue work on TenFourFox FPR8, having slept peacefully and properly over the entire holiday weekend. Now that same-site cookies are working, it's time to get some sort of basic CSS grid support operational (or at least whitelisted for those sites that need it), and I still want to finish idle callback support and date-time picker support. After all, even though the T2 is getting closer and closer to being suitable as my main computer, there's still a lot I'll need to keep the G5 around for, so I'm certainly not planning to get rid of it. Or, you know, "put it to sleep" in the veterinary sense. Just because it's old doesn't mean it's useless.

Monday, May 21, 2018

Spectre Number 4, STEP RIGHT UP!

Updated based on IBM's documentation.

In the continuing saga of Meltdown and Spectre (tl;dr: G4/7400, G3 and likely earlier 60x PowerPCs don't seem vulnerable at all; G4/7450 and G5 are so far affected by Spectre while Meltdown has not been confirmed, but IBM documentation implies "big" POWER4 and up are vulnerable to both) is now Spectre variant 4. In this variant, the fundamental issue of getting the CPU to speculatively execute code it mistakenly predicts will be executed and observing the effects on cache timing is still present, but here the trick has to do with executing a downstream memory load operation speculatively before other store operations that the CPU (wrongly) believes the load does not depend on. The processor will faithfully revert the stores and the register load when the mispredict is discovered, but the loaded address will remain in the L1 cache and be observable through means similar to those in other Spectre-type attacks.

The G5, POWER4 and up are so aggressively out of order with memory accesses that they are almost certainly vulnerable. In an earlier version of this post, I didn't think the G3 and 7400 were vulnerable (as they don't appear to be to other Spectre variants), but after some poring over IBM's technical documentation I now believe with some careful coding it could be possible -- just not very probable. The details have to do with the G3 (and 7400)'s Load-Store Unit, or LSU, which is responsible for reading and writing memory. Unless a synchronizing instruction intervenes, up to one load instruction can execute ahead of a store, which makes the attack theoretically possible. However, the G3 and 7400 cannot reorder multiple stores in this fashion, and because only a maximum of two instructions may be dispatched to the LSU at any time (in practice less since those two instructions are spread across all of the processor's execution units), the victim load and the confounding store must be located immediately together or have no LSU-issued instructions between them. Even then, reliably ensuring that both instructions get dispatched in such a way that the CPU will reorder them in the (attacker-)desired order wouldn't be trivial.

The 7450, as with other Spectre variants, makes the attack a bit easier. It can dispatch up to four instructions to its execution units, which makes the attack more feasible because there is more theoretical flexibility on where the victim load can be located downstream (especially if all four instructions go to its LSU). However, it too can execute at most just one load instruction ahead of a store, and it cannot reorder stores either.

That said, as a practical matter, Spectre in any variant (including this one) is only a viable attack vector on Power Macs through native applications, which have far more effective methods of pwning your Power Mac at their disposal than an intermittently successful attempt to read memory. Although TenFourFox has a JavaScript JIT, no 7450 and probably not even the Quad is fast enough to obtain enough of a memory timing delta to make the attack functional (let alone reliable), and we disabled the high-resolution timers necessary for the exploit "way back" in FPR5 anyway. The new variant 4 is a bigger issue for Talos II owners like myself because such an attack is possible and feasible on the POWER9, but we can confidently expect that there will be patches from IBM and Raptor to address it soon.

Wednesday, May 16, 2018

A little Talos of your very own

I haven't had as much time to work on getting QEMU and Firefox functional/useable on the Talos II over the last few days because of work complications (I'll be reporting on that in a few weeks), but Raptor has heard those of you who are still suffering sticker PTSD from the Talos II and announced the Talos II Lite.

Yes, think of it as the Mac mini G4 to the Talos II's Quad G5. This comparison is not completely inappropriate because the T2L has only one CPU socket (the T2 has two) and thus only 24 PCIe lanes, split amongst an x16 and an x8 (the T2 fully loaded has two x8s and three x16s), and "only" 8 DDR4 slots (the T2 has 16). You can still cram one of the 22-core demons into one of those, though. Starting price is "just" $1399.99, though as with the Talos II the CPU is extra ($375 for 4-core to $2575 for 22-core), the RAM is extra ($255 for 16GB to $2950 for 128GB), and the storage is extra (Microsemi SAS starts at $300 plus drives, or a Samsung 960 EVO NVMe 500GB for $350, or a four-port SATA controller for $50 plus drives). You can also add the same Radeon WX 7100 workstation card that's in the big T2 ($800), too, or just use the same onboard VGA controller that comes with the T2 (built-in). It has USB 3.0 and dual Gig Ethernet, just like the big fella, though it doesn't seem to come with a BD-ROM.

However, the mini:Quad analogy falls down when you look at the actual size of the Lite. It, too, is an EATX behemoth, despite the leaner spec. Personally I would have hoped for something a little more manageably dimensioned. Raptor is taking about offering a smaller board but that would require a redesign and this was probably an artifact of getting it launched cheap(er)ly.

So would I have saved money with my T2 going Lite? Let's price it out: $1400 for the system (includes 500W PSU and EATX case), $595 for the octocore POWER9 (my T2 has two 4-core chips), $535 for 32GB ECC DDR4 RAM, $350 for the SAS card, $800 for the AMD Radeon WX 7100, $50 for the 4-port SATA card (this came installed "free" in my T2) and $350 for the 500GB Samsung NVMe SSD. Sticker price for that configuration is $4080 plus applicable tax and shipping; I repriced the same configuration for the Talos II and got a sticker cost of $7360, about $250 more than what I paid personally (the benefit of being an early adopter), so let's say a cost difference of $3300. That's substantial and a whole lot more palatable. $4080 is actually within Quad G5 range -- I paid not much less than that for my Quad G5 back in the day with the 7800GT and 8GB of RAM. A cheap SATA DVD-RW or something wouldn't add much more to the price if you want an optical drive.

There's a small problem here though: the Lite can't actually accommodate that loadout because there's not enough PCIe slots to get it all in there. In fact, I've got another 1GB NVMe drive to install in my T2, and I'm probably going to pull the now unused Sonnet FireWire/USB PCIe card (I prefer FireWire hubs) from the G5 to install in it too, which may mean temporarily pulling the SAS card until I'm ready to populate the front bays. Also, the Talos II out of the box doesn't support PCIe bifurcation, so I really do need both those slots for my SSDs. Per Raptor it can: with changes to the machine XML definition it could be made to "trifurcate" the x16 endpoint on slot 3 (CPU 2, PHB2) into an x8 and two x4, but that would mean that the available 4-way M.2 NVMe multicards would only have at most three slots available, and the system doesn't ship that way anyhow. Besides, even if you did get bifurcation working on the Lite, you'd only have the remaining x8 for anything else which couldn't be used for an x16 workstation video card. UPDATE: Per Raptor, the Lite's x16 can't be bifurcated due to a hardware limitation, so that is only an option for the big system.

But let's say you're not a maniac like me and you want a basic "budget" config. Let's drop the workstation card and the SAS card, and drop to a 4-core with 16GB, and we have a $2430 system. Wow! Not bad! You've still got the NVMe card and storage expansion over SATA, and you've still got USB ports for audio and the onboard VGA. But you've used up all your PCIe slots, so let's hope you don't need anything else to go internal (let alone 3D acceleration). If you really want that x16 slot back, drop the NVMe card and add some SATA drives ($2080 + devices), but now you're starting to strip this system down more than you might like to, and it doesn't get much cheaper that way.

Overall, that $3300 really does translate into greatly improved expandability in addition to the beefier power supplies, and thus it was never really an option for my needs personally. Maybe my mini:Quad analogy wasn't so off base. But if you want to join the POWER9 revolution on a budget and give Chipzilla the finger, as all right-thinking nerds should, you've now got an option that only requires passing a kidneystone of just half the size or less. It ships starting in July.

Another interesting thing Raptor pointed out: in the Phoronix performance tests, the Talos was running with full Spectre and Meltdown protections, but the x86 wasn't! Boooo! And if you really want to turn Spectre protections off on the Talos for even more grunty, you can do that. Meanwhile, as we speak, Intel is making people take down their firmware documentation and trying to stymie efforts to reverse engineer them. What system would you rather support?

Monday, May 14, 2018

Secure mail on Power Macs is not a good idea

Arguably it hasn't been a good idea for awhile, but the EFAIL hack now makes it possible to decrypt even previous encrypted messages as well as current ones. All known mail clients for PowerPC OS X that can render HTML are vulnerable, including Apple Mail, Thunderbird and Tenfourbird. Earlier clients that lack this functionality are not vulnerable to this specific exploit, but their encryption capabilities are likely insufficient or not otherwise current, so they should not be considered secure either.

The EFAIL vulnerability is not as severe as it might sound because a key requirement is that an attacker already have access to the encrypted messages. If you used the tips in our security recommendations for PowerPC OS X to improve the security of your computer and your network connection, the odds of this occurring are not zero because the attacker may have already collected them in the past through other means, but are likely to be fairly low with the holes that remain. The risk can be mitigated further by disabling HTML rendering of E-mail (that means all E-mail, however, which might be a dealbreaker), and/or disabling automatic decryption of such messages (for example, I already cut and paste encrypted messages I receive into GPG directly in a Terminal window; my E-mail client never decrypts them automatically). A tool like Little Snitch could also be employed to block unexpected accesses to external servers, though this requires you to know what kinds of access would be unexpected for such messages.

Even with these recommendations, however, there may be other potential edge cases such that until someone(tm) updates Thunderbird or another mailer on Power Macs, secure encrypted mail on our systems should be handled with extreme caution and treated as if it were potentially exposed. If you require this kind of security from your E-mail and you must use a Power Mac, you're probably better off finding a webmail service with appropriate security and using TenFourFox (the webmail service then handles this), or building and using an E-mail client on some other system that is more up to date that you can access remotely and securely (which is what I do myself).

Friday, May 4, 2018

TenFourFox FPR7 available

TenFourFox Feature Parity Release 7 final is now available for testing (downloads, release notes, hashes). There are no other changes in this release from beta 3 other than remaining outstanding security patches. It will go live Monday evening Pacific time as usual assuming no showstoppers over the weekend.

Wednesday, May 2, 2018

A semi-review of the Raptor Talos II

After several days of messing with firmware and a number of false starts, the Talos II is now a functioning member of the Floodgap internal network. It's under my desk with my other main daily drivers (my Quad G5, MDD G4, SGI Fuel and DEC Alpha 164LX) and shares a KVM. Thanks to the diligent folks at Raptor, who incredibly responded to my late night messages at 2am Pacific, the fans are now much more manageable and I'm able to get proper video output from the Radeon WX 7100 (though more on that in a minute). As proof of its functionality, I'm typing this blogpost on the Talos instead of on the G5. Here it is in its new home:

I'll call this a "semi-review" because, well, the system is a work in progress and getting the most from it will take time. Relatively little is optimized for PowerPC these days, and even less still for little-endian PowerPC or POWER9 in particular. If you want performance benchmarks, you can read Phoronix's performance tests which are substantially more thorough than anything I could gin up. This is about my experiences with the unit now that I've been using it most of today with my early firmware issues now largely corrected.

For what's in it, see my unboxing photographs from a few days ago. This system is best described as a middle-road configuration now that the 22-core chips are becoming available. It contains two four-core Sforza POWER9 processors on a 14nm process at 3.2/3.8GHz with 512K of L2 and 10MB of L3 per core; there is a discrepancy with the wiki which says 3.1/3.7 but you can read Raptor's spec sheet. SMT is available. By having both processors installed, all of the PCIe slots in this machine are unlocked (this was a deliberate design decision for efficiency, not to make you buy hardware you didn't need). All of the options in this unit are factory-installed: 32GB of ECC DDR4 RAM (maximum 2TB), an AMD Radeon Pro WX 7100 workstation video card (roughly a hopped-up RX 480), a Samsung 960 EVO 500GB NVMe SSD on a PCIe card and a Microsemi PM8068 SAS 3.0 controller. The machine comes stock in a Supermicro CSE-747 EATX case with two redundant 1400W power supplies, a SATA controller, onboard VGA, onboard USB 3.0, onboard 2xGigE network ports (Broadcom BCM95719), onboard RS-232 serial and an LG Blu-ray drive. A recovery disc with the factory firmware and manual is included. Sticker price was approximately US$7200.

No operating system is installed except for Petitboot (more in a moment). This machine should eventually run anything that supports it (of course it will run NetBSD, at least someday), but your sole option right now is Linux, and bleeding edge Linux at that: Raptor's excellent tech support team tells me that kernel 4.13 is minimally required and 4.16 is strongly recommended. This greatly limits your choices out of the box especially if you don't already have another Linux system to support bringing this one up. I didn't, so I selected Fedora 28, which supports ppc64le and has kernel 4.16. As of this writing, the final release of 28 has just hit the streets, so that's very timely. Officially Fedora only supports the Server flavour on ppc64le, but we can convert that to a Workstation version after it's installed.

The system boot sequence has several stages. You can read about them in a bit more detail on the RCS Wiki, but the breakdown is not unlike that of a modern POWER server, since this is mostly a modified OpenPOWER design. Immediately when power is applied, the system boots the "BMC" Baseboard Management Controller, which runs on an ARM6L service processor. This sits idle when the main processors are powered down. When the power button is pressed, the BMC starts the Initial Program Load (IPL) process on the main POWER9 CPUs from PNOR flash. Through a complex six-stage process the IPL terminates with loading Petitboot, a simple loader inside a tiny Linux environment called Skiroot. Since Petitboot is running in a tiny Linux, its presence simplifies driver support for the main operating system by handling platform functionality directly via the OpenPOWER Abstraction Layer. Petitboot, in turn, kexec()s into the OS kernel and, at least in theory, away you go.

Initially the fans came on at IPL at a terrific volume such that my wife and I could not reliably hold a conversation in the same room (no exaggeration). In addition, while I could get Petitboot to display on the Radeon card, the operating system wouldn't appear -- I had to use the onboard VGA to boot, which was inconvenient for my KVM and meant my expensive workstation card was doing nothing. Raptor's tech guys listened to my frustrated pleas and notified me immediately when the most current firmware was available. When I loaded this firmware on the system, it worked beautifully for about 10 or 15 minutes and then started freaking out, failing to see the NVMe, kernel panicking on the Fedora disc that it used to boot from, etc. Raptor got me another command to blank the GUARD partition on the PNOR flash to try to reset it, and the machine started working! In fact, I've been using it since about 11am today non-stop, so I consider that to be an excellent burn-in period. Oddly, I can't get Petitboot to appear on the WX 7100 output now, but the OS does, so it's not a big deal (I can just switch to VGA if I need to get into the bootloader until that gets fixed). This all happened literally within the space of a few days. The fans rev up and down periodically, which can be a bit disconcerting next to my usually quiet Quad G5, but they are no longer anywhere near as shrill or constant and I only notice them if the room is warm.

Power usage, incredibly, is quite modest for a machine of this specification. When you connect the power, the BMC sits idle at around 13W with a very quiet fan running. Starting IPL, the fans do still come on full blast at least initially and power usage jumps immediately to 143W. This climbs slowly to 212W by the time you hear the beep from the system indicating Petitboot has started. Petitboot then starts Fedora and once Fedora has booted and we are at the login screen, power usage drops back to around 150W and the fans automatically throttle down. I got out my infrared thermometer and checked the heat coming out the back, and found it was a very reasonable 91 to 99 degrees Fahrenheit. (The cat likes the G5 better for heat.) Most tasks barely moved the needle after that. I did some installations with dnf and the power usage barely rose to 160W. Compiling OpenSSL got it up to 177W. This is all less than the Quad G5 next to it, which right now is reading 238W on the UPS while sitting largely idle in Reduced power mode. On the other hand, I'm not using the video card very heavily, so this output could jump quite a bit once I get some games running on it. There are also no drives connected to the RAID yet, just the NVMe SSD.

You can expect an upgrade path with this hardware as well. Besides accepting any hardware accessories that are compatible with Linux (though see below), Raptor is planning to make additional processor options available if you have the thermal headspace and the power capacity, even this 22 core monster. Unlike the Quad G5, this system shouldn't be a dead end.

So that's the hardware. Let's talk about the software. This isn't under Raptor's control necessarily, but it will play into your decision-making process should you make an investment in one.

There are really two kinds of customers for the Talos II: people like me who dislike x86 on technical grounds and Intel's continued hegemony and wish to support alternative architectures of comparable performance, and people who are paranoid and want a system that is far less of an opaque closed system that they can audit and trust than what passes for commodity hardware these days. There is naturally some overlap between these two groups. The second group will probably put up with a little more inconvenience for the sake of ultimate privacy than the first group, which is more concerned about functionality. You should think long and hard about where you fall here, because it will affect how you perceive the system.

The major selling point to the second group is that the firmware is fully open-source and auditable even down to the FPGA level. Schematics are included! You can download and build your own FPGA flash image, your own BMC flash image and your own PNOR flash image. In fact, you are expected to, though Raptor provides pre-built versions assuming you trust them and their warrant canary. As long as you don't brick the BMC -- though this is doable if you are incautious -- you can play around with Petitboot and Skiboot pretty much at will and just reflash if you screw it up. Programming the FPGA means you'll need your own SPI programmer, but there's a JTAG port on the board and you can plug right in. Note that this scheme isn't perfect because you still have to trust a certain amount of the other firmware in the system, mostly in the various peripheral devices, but it's clearly better than what you'd get from any other system and it's a strong start towards reclaiming control of our own machines. Although I haven't tried writing my own custom firmware yet, it's very easy to build and flash the prefab releases, and the process is well documented. To upgrade to the current firmware from the v1.02 my machine came with did not require flashing the FPGA, so I could do it all from my G5 by talking to the BMC over SSH.

For the first group, however, that alone won't be satisfactory, because we actually want to use this thing as a computer. Frankly, my plan is to make this the Power Mac G5 successor that never was. It certainly has the specs for it. Unfortunately, this part is the bit that's not yet complete. I haven't tried other operating systems other than Fedora 28 yet, but I can't imagine the experience is much different, so take these observations at face value.

Because Fedora doesn't offer a direct download for Workstation on little-endian 64-bit PowerPC, you have to install Server first, and then switch to the Workstation environment. This will download the remaining missing pieces; I selected the default Workstation environment, which is based on GNOME. Hopefully future distros supporting this machine will do better than this process. While in use the system is perfectly responsive but seems slower than it ought to be at times, particularly compared to the Quad G5, though this is probably an unfair comparison. The G5 is running Mac OS X 10.4.11, an OS written by its manufacturer and highly optimized for it. The Talos II has to contend with an OS for which it is not the primary target, nor one that is particularly tuned for any PowerPC system.

There are various glitches and many things don't work yet. The first and most important deficiency is that I still can't get amdgpu working in Xorg, so I'm using framebuffer support (fbdev). This means the video card is still going largely underutilized. I expect this to improve as Polaris support improves, but it's not there yet. For this reason I haven't even bothered trying to load any games on it so far.

Multimedia is also limited because I don't have a sound device. lspci alleges the WX 7100 has some sort of audio support, but the open source drivers don't currently support it. I'll likely solve this problem with some sort of USB audio out in the meantime, but that's suboptimal. I haven't tried playing DVD or BD movies on it yet either for that reason.

Fedora didn't like the GBU-421 Bluetooth USB dongle I use with the G5. The G5 needed no drivers and it just "works," but GNOME doesn't see it. I had to transfer the picture above from my phone to the G5, and then to the Talos.

A few of the included applications either misbehave or don't work at all, though most fortunately do. The GNOME Software application kept complaining about incorrect checksums, but dnf was fine from the command line. Firefox 59 crashes with a segmentation fault on start-up (like I say, I guess I've got a project now). GNOME Web (formerly Epiphany) does work, but it's WebKit and I don't like that, and it too is not very well optimized. It does pretty well, though, considering; it got 2455ms on SunSpider, which would seem like a dismal number given that the Quad G5 managed 2255ms in TenFourFox, except that TenFourFox has a JIT and GNOME Web here is running interpreted, and TenFourFox is compiled with CPU optimizations specifically for the G5 while GNOME Web and the system WebKit have no specific optimizations. I'm also unhappy there's no Gopher support. On the other hand, you would expect YouTube videos to be a slideshow (no JIT, little or no SIMD), and yet they play at a surprisingly good framerate, just muted. This post is being written in GNOME Web.

However, much of the rest of it does work. Since I intend this to be a successor to my G5, I spent most of the afternoon making GNOME more Mac-like. Using Fondu, I copied the Lucida Grande font from Tiger and converted it back to TTF (to compile Fondu on the Talos, configure it with ./configure x86_64-unknown-linux-gnu, since it doesn't know what the heck a little-endian PowerPC is) and installed it. I then installed the GNOME Tweaks tool with dnf and a Mac GNOME theme and Dock extension. (Some other ideas are on this how-to.) I switched the system font to Lucida Grande in the Tweaks tool, disabled hinting entirely and left it with greyscale antialiasing, turned on User shell themes in Tweaks, and wrote a minimal shell theme to make the top bar more like a Mac menu bar. It's not perfect, but it's a good start. I'll provide it later if people are interested.

To get my Mac shortcut keys back, I installed AutoKey (autokey-gtk), and started making equivalents. A few clashed with GNOME, which I changed from Settings, and I altered a couple others in Terminal, but they mostly just worked with everything else including GNOME Web.

Let's bottom line it. As far as value for money, the machine is well-assembled, solidly built (if in an unexciting enclosure) and consists of quality components. I think the above paragraphs also demonstrate that the level of support from Raptor is absolutely commensurate with what you would expect for a $7000+ computer. Frankly, it's one of the best technical support experiences I've ever had with any system. Part of that is undoubtedly the low production numbers and highly technical engineering audience, but I have never felt like the machine was an unrecoverable doorstop even when it wasn't suitable for use yet.

Software, however, is still a work in progress. You should not expect a 100% functional system at the end and you don't even get a functional system out of the box. Not only will you have to install an OS and go through that process, you're also pretty much guaranteed that something won't work when that part is done. And even when everything you need actually is working, nothing is optimized for it; many things will run abnormally slowly until "someone" (tm) does this work. It's been a long time since PowerPC was a common desktop platform, so many of the optimizations Intel systems take for granted just don't exist, and some desktop apps aren't even tested.

But all of these things are correctable. The hardware is solid. The firmware rudiments are coming together; look at how quickly this machine evolved in just a few short days. Software is likely to be an easier nut to crack on the little-endian Talos than on previous big-endian PowerPC systems, too. Assuming there aren't dependencies on complex assembly code blocks, more code is likely to "just" work with fewer or no modifications because the assumptions made for mainstream x86 will now largely apply here as well. This depresses me personally since I think in big-endian, and have used big-endian systems for decades, but that's the way things are now.

I'm looking forward to this system becoming my daily driver and it might even happen in just a few months. I need to get Firefox working, and I need to get QEMU optimized to run my old Power Mac software. That's all doable. Once the video card and sound options are fixed, I can even start using it for multimedia and games, and the G5 can then become a well-cherished part of my collection.

This is a fully free system you can live with. This is a fully free system that can kick ass. The promise was kept and the dream is real. It's time to get busy.