Category Archives: Computers

I ran into a delightful irony trying to help a student get set up for the embedded systems lab I’m running this semester: Neither Keil MDK ARM (a first-class ARM development environment) nor the Stellaris ICDI Drivers (TI’s programming/debug interface … Continue reading

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ThinkPad 560E

Complete ThinkPad 560E system.

I’ve been idly looking for one of the mid-90s ThinkPads known to have perfect OpenStep/Rhapsody support for years as a fun collector piece, but been unwilling to pay eBay prices. The other week I scored a pristine IBM ThinkPad 560E for $20 in a Shopgoodwill auction, below is notes on getting it up and running, plus some relevant history and plans.

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Apple 12″ Macintosh RGB Monitor Recap

This post is a retro post on a retro topic – a repair I did in 2017 on a monitor made in 1991. I got a question about (probably) the same problem in another venue and realized I never put it online. I managed to dig up my pictures and notes, so there is useful information to be shared.

My 12″ RGB Display is getting sad.

The end of my (2016) post about Recapping my Macintosh LC I discovered that my matching Apple 12″ Macintosh RGB Monitor ( M1296 ) was going pear-shaped, and speculated that I’d need to recap it.

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I have a machine with SSH exposed on one high-numbered nonstandard port forwarded through a NAT. A few days ago I noticed some log noise about failed SSH logins and turned on fail2ban with sane defaults. It banned almost 300 … Continue reading

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Macintosh SE Health Check

I had my dear old Macintosh SE out for a health check as I slowly extract my vintage computer collection from the (unconditioned) place I’ve been keeping it at my parents house to the basement of the place I’m renting. It had a couple interesting findings that seem worth putting online, including another floppy drive rebuild and a slightly elaborate fan replacement.

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SC’19

Even though I haven’t done any work in that area in years, I got pulled into the Supercomputing conference again this year.  Can’t complain, it’s always fun.  UK’s combined booth looked good this year

Far corner is a little updated TinyTitan style Raspberry Pi cluster with a interactive CFD demo running on it that the CCS folks have been playing with, that thing in the leading corner is a cute flip-dot “quantum computer” model we built as a front-end for a 16-bit instance of Hank’s parallel bit-pattern computing system that can do quantum algorithms efficiently on a conventional platform – set in the corner of the booth like

You don't need quantum physics to perform quantum compution. Change my mind.

He did surprisingly well with this approach.

The exhibit floor was even more dominated by cooling tech this year. Exciting finds are the coming of very open (Open Compute Project, Coreboot + Open Network Linux) white-box 100GBE switches at reasonable prices, Fujitsu’s A64fx ARM with SVE and obscene memory bandwidth parts actually landing in systems, and (just because it tickled me) pre-wired fully populated Clos topology 100G cable harnesses.  The other dominant species was AI woo; my body is ready for AI Winter 3.0.

Google photos album of my annotated show floor photos is here.

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Server Updated

The server that hosts this page was updated from Debian Jessie (8) through Stretch (9) and onto Buster (10) over the course of a few hours today. It involved surprisingly little suffering and should not affect functionality, please let me know if you find anything left in a broken state.

I didn’t realize how long it had been since I did any manual maintenance here, apt unattended upgrades, certbot, and a few scripts for user-installed package upgrades and backup had done such a good job maintaining things just visibly enough to know it was being taken care of that I’d let it get past-due. Most of my other individually-installed boxes are Arch rolling-release machines that require a few minutes of attention every month or two, so they don’t have the periodic major breaking maintenance issue to the same degree.

Now I can let it take care of itself again until 2022 or thereabouts.
A few notes that may be useful to others under the fold.
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Masters in Electrical Engineering (Finally) Collected

That MSEE that I was going to finish in 2011, 2013, and 2015? I blew a couple months in the last year to get all the ducks in a row and actually collected it before the credits expired.  Huge thanks to Dr. Aaron Cramer, the current DGS for UK’s ECE department who went to great lengths to deal with the bureaucratic issues my lackadaisical attitude about credentials created.

Thesis is “A Compiler Target Model for Line Associative Registers” document and defense slides with notes linked.

The LARs design is fundamentally interesting, but the compilation work the MS is based on is not my favorite work I’ve done.  The core initial assumption (that LAR allocation and register allocation were more-or-less the same problem) turned out to be very, very wrong, and the implications of that wrong assumption turned out to be far reaching, turning a 2-year MS into a decade-long ramble. It’s not as depressing as I thought it would be when I tried to finish in 2015 (and was blocked by bureaucratic fuckery) because I did eventually determine that LARs aren’t subject to the “you can’t statically schedule around dynamic memory behavior” thing that doomed VLIWs, and in fact LAR allocation can be done greedily in ways that register allocation cannot.

The thesis is more or less assembled from three false starts plus the final effort; my initial research start with the wrong assumptions, my “oh, we’re wrong, but it’s OK” pass, and my “oh shit, we’re screwed, this won’t work and there his historical evidence to show it” pass, plus the final “I’ve figured out how this is tractable and possibly even desirable, but I’m out of time and fucks, so here’s the rough solution” pass.

I formatted the thesis in LaTeX (of course), using the ukthesis.cls class I found on the UK Math site that Eric Stokes, a former student, made a decade and change ago since UK is too chickenshit to provide a valid one of their own.  I did have to hack it a little bit, turn off some features, tweak the front matter, etc. to make it acceptable to the graduate school, and update a few things (eg. adjusted to use biber for references).  There are a few things in the document that should be in the class, and things in the class that should be in the document, but the easy-to-fix stuff is fixed.  Minimal example pulled from the accepted version with makefile and such here to save future students the extra annoyance.

The presentation is in beamer using the Owl theme, which was a delightful recent discovery – someone has made a beamer color scheme with a dark background and colors that actually look good on a projector. I (much to one of my committee member’s disappointment) went with the bullets-to-keep-me-on-track-while-I-talk style slides instead of my usual “amusing semi-relevant pictures to key off of” scheme.

It’s nice to be done and only have one, significantly less depressing, long-term academic project people are grumpy about my progress on.

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E7250


I picked up a refurbished Dell Latitude E7250 (Dell’s “Premium” 12.5″ laptop, just over a generation out of date) because the little loaner Inspiron 11-3000 I’d been using as my carryin’ around laptop had become unacceptably shitty at essentially all the things I wanted to use it for. The E7250 is Superb, with notes:
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SC17 Notes

I’m back from SC’17, and to complete annual tradition, some thoughts:

  1. Chinese manufacturing is winning the day: The Nov’17 Top500 shows three of the top 5 and roughly 60% of the total compute power on the list are Chinese machines. Especially domestic-design Chinese machines (The ShenWei SW26010 in #1 are pretty thin on public details, but smell a lot like a better implementation of the Cell idea). Last time this kind of trend started (in Japan) the US spent a boatload of money on development, but I don’t think there is the political will for that sort of thing right now.
  2. Linux all the things: 100% Of the Top500 are now running some sort of Linux. Linux is a nice thing, but the mono-culture is sort of alarming.
  3. Singularity: Greg has a long history of solving real problems in the ecosystem (Warewulf, CentOS, etc.) in very pragmatic, very open ways. About 18mo ago he posed about a prototype container scheme suitable for HPC apps he’d been playing with. It’s now everywhere and running on everything because it solves compatibility problems, portability problems, reproducibility problems, archiving problems, workflow problems, verifiability problems, administration problems, and, unlike most containerization schemes, isn’t made of inefficient ill-conceived web-hipster bullshit. They’ve formed a little company to support it, which was second only to Nvidia in terms of brand presence. It has moved considerably up my list of things I need to learn.
  4. Fidget Spinners: So many fidget spinners on the show floor. With LEDs. And branded metal bits. Chinese mass production has also overtaken the swag in the industry.

Also, a pile of pictures from the show floor.

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