[koko] knowing and accepting limitations

It seems I am easily distracted. One thing leads to another. Inquiries spur new thoughts. Anomalies suggest investigation. Surprises remind of well-worn adages, e.g., newer isn’t always better, particularly regarding software. But, I keep on keeping on.

Though I’ve been aware of Lions’ A Commentary on the UNIX Operating System since 1983, I’ve never taken the time to study Lions, or any *nix kernel, thoroughly. From time to time I’ve started looking at Lions, even though I don’t really know the PDP-11/40, and more recently looked at the xv6 successors based on x86 & RISC-V.

Pondering which emulator/platform to use, perhaps even a PDP-11 emulation with Open SIMH, I remembered that I had not followed through on my intentions to better document installing and working with Dell Unix on 86Box, after an inquiry from someone trying to work with the materials cited in Dell Unix sustainable!. Though xv6 seems to eschew 86Box in favor of QEMU, it seemed that responding to that inquiry was the next right thing to do.

The plan was to recreate what I had done in 2021 with fresh Windows 11 and the latest 86Box, using Snipping Tool to create a video of everything. After figuring out how the 86Box voluminous options had changed so much between Version 2 that I used in 2021 and current Version 4, the base Dell Unix install went ok. Expecting 4+ hours to install all the options with NFS, “newer isn’t always better” then came to mind, stunned to see screen after screen of NFS timeout messages (mostly not shown here) and 21 hours to complete:

/ # time pkgadd -d /mnt/netinstall all > pkgadd.out 2> pkgadd.err
NFS server not responding still trying
NFS server ok
NFS server not responding still trying
NFS server ok
real    20h37m3.09s
user    1m30.98s
sys     2m20.44s
/ #

Superficial checks showed that everything had worked, in spite of the apparent network errors and slowness. I took a step back, trying to understand.

I’ve now completed replicating the process using 86Box versions 2, 3 and 4, on the Windows 11 machine and the prior Windows 10 machine (both fully MSFT updated), making videos on the Windows 11 machine, and benchmarking to conclude that, at least in this use case, with these 86Box settings, networking broke between versions 3 and 4. This assertion is largely based on the NFS errors described above and FTP transfer speeds for fetching a 116MB cpio file: 14K bytes/sec on Version 4, 120K bytes/sec Version 3, 150K bytes/sec Version 2.

Though there are predictable variations, processor and I/O benchmark results for Dhrystone 2.1, SPECint89 and Bonnie are fairly consistent — see “eye-test” spreadsheet.

There are links to videos and updated install instructions at https://technologists.com/DellUnix2.2.1/.

Now I intend to get back to other projects, trying to judiciously add #ifdef’s to SPECint89 sources to get them to work with modern compilers and operating systems, getting serious about studying Lions, pursing musical endeavors, …

In doing so, I’ll have to know and accept my limitations, know I’ll get distracted again, …

“The only thing I knew how to do
Was to keep on keepin’ on like a bird that flew”
(1975) “Tangled Up In Blue” – Bob Dylan

[Update 2/17/24: I’m thinking I want to have a bunch of emulators available on my M1 MacBook Pro, so it seems appropriate to replicate the 86Box/Dell SVR4 efforts there. I couldn’t get 86Box 4 to work there, 86Box 2 doesn’t claim to work there, but so far I’m pleased with 86Box 3.11. Networking seems much faster than I imagined — total NFS install time was about 30 minutes(!) and the ftp cited above measured 780Kbytes/s.
Update 2/19:24: 86Box 3.11 on Fedora 39, on the same i5 machine as with Windows 11, ftp measures 690Kbytes/s but relatively poor Bonnie/Dhrystone/SPEC89int. Couldn’t get PCAP to work with Ubuntu on the i5 machine or Raspberry Pi 5 with Pi OS. I also tried Fedora 39 on a Pi 4 but couldn’t get PCAP to work.]

One Response to “[koko] knowing and accepting limitations”

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