pjdesno

8 ms·

61.
by pjdesno 10mo ago
> $8 trillion of CapEx means you need roughly $800 billion of profit just to pay for the interest That assumes you can just sit back and gather those returns indefinitely. But half of that capital expenditure will be spent on equipment t
62.
by pjdesno 10mo ago
To expand on rahimnathwani's comment below - the big capital costs of a data center are land, the building itself, the power distribution and the cooling. You can get a lot of land for a million bucks, and it doesn't cost all that
63.
by pjdesno 11mo ago
Note that Claude Shannon's MS thesis was about re-discovering the work of an obscure British analytic philosopher, whose work from about 100 years earlier had been almost completely forgotten. (perhaps a few philosophers and mathematic
64.
by pjdesno 11mo ago
Here's the case - a judge froze the company's assets, which meant that if you had any of your personal property on the premises, you were SOL. https://www.upi.com/Archives/1991/03/28/Court-freez
65.
by pjdesno 11mo ago
Bankruptcy can be a bitch. I remember a case (maybe 30 years ago?) where a local health club chain went bankrupt, and anything anyone had left in their lockers was stuck there until the judge ruled on the case.
66.
by pjdesno 11mo ago
The mere fact that the title says "Department of War" is a raging red flag...
67.
by pjdesno 11mo ago
The original poster got pretty much all of Debian running in Fil-C, in a fairly brief amount of time. Re-writing even a single significant library or package in Rust would take exponentially longer, so in this case Rust would not be "a
68.
by pjdesno 11mo ago
> What would a system that rewards people for quality rather than volume look like? Hiring and tenure review based on a candidate’s selected 5 best papers. Already standard practice at a few enlightened places, I think. (of course this a
69.
by pjdesno 11mo ago
I'm involved in a fairly large academic cloud deployment, sited in a 15MW data center built and shared by a few large universities. There are huge advantages of scale to computer operations in a few areas: - facility: the capital and r
70.
by pjdesno 1y ago
Is anyone surprised that the systemd folks basically said "fuck you, we'll do what we want to" to everyone else?
71.
by pjdesno 1y ago
When I was an intern in the mid-80s we were cross-compiling for a 68000-based device (on a VAX, no less) but had our own version of the C library, supposedly because of some legal issues with the compiler vendor. Part of this library was th
72.
by pjdesno 1y ago
There’s a latex editor for the Mac with real-time typesetting (I forget the name) that I used very early on for fairly high-value paper submissions. (not my dissertation - that’s long in the past) I trusted it because (a) I had a downloaded
73.
by pjdesno 1y ago
Have you ported the USENIX or ACM paper templates? I dont see how you can claim to be useful for scientific documents if you don’t handle the standard publication templates.
74.
by pjdesno 1y ago
I run into a fair number of good undergraduate students who are terrible phd students. Same problem. They did well solving problems that someone already knows the answer to, applying concepts that were explained to them in class. Suddenly t
75.
by pjdesno 1y ago
Don’t forget that ARM was originally the Acorn RISC Machine.
76.
by pjdesno 1y ago
If you click through to the follow up article, you’ll find that the city covered the cameras with black plastic. Sometimes low tech solutions work pretty well. And since the cameras are under contract to the city, on city poles, I doubt the
77.
by pjdesno 1y ago
Because they made something different with the same process, instead of making the same thing with a different process. Feature size didn’t get any smaller. (or, rather, you get the order of magnitude improvement without it, and those gains
78.
by pjdesno 1y ago
The best story I heard about machine learning and radiology was when folks were racing to try to detect COVID in lung X-rays. As I recall, one group had fairly good success, but eventually someone figured out that their data set had images
79.
by pjdesno 1y ago
It’s mostly 3D, not process. 3D flash is over 300 layers now. The size of a single 300-bit stack on the surface of the chip is bigger than an old planar cell, but that 300x does a lot more than make up for it. 3D NAND isn’t a “process impro
80.
by pjdesno 1y ago
Oh, and by “full seek” I mean the time it takes to read the max block number (inner diameter) right after reading the min block number (OD) subtracting rotational delay. You can do this test yourself with fio —readonly and root access to a
81.
by pjdesno 1y ago
IT’S NOT 4 MS. That’s a bogus number from an ancient slide deck for a class in 2001 or so, that’s misled generations of folks googling for the answer. Note also that the outer tracks are longer (google ZCAV) and hold more data, so seeks acr
82.
by pjdesno 1y ago
I didn’t check the article. When I was reviewing it for publication I ran a couple of tests and found more like 18 on the devices I tested, but I’m sure there are some that do 15. 25 is probably on the slow end. (although I’ve never tested
83.
by pjdesno 1y ago
Originally Ceph divided big objects into 4MB chunks, sending each chunk to an OSD server which replicated it to 2 more servers. 4MB was chosen because it was several drive rotations, so the seek+ rotational delay didn’t affect the throughpu
84.
by pjdesno 1y ago
Please fix the seek time numbers - they’re wildly in accurate; full platter seek is more like 20-25ms. I tried chasing down where the 8ms number came from a while back, and I think it applies to old sub-100GB 10K RPM high-speed drives from
85.
by pjdesno 1y ago
The “drain time” for a 30TB drive is probably between 36 and 48 hours. I don’t have one in my lab to test, or the patience to do so if I did.
86.
by pjdesno 1y ago
Seems to indicate the storage underneath might be similar in cost and performance, and this might in fact really be similar. Not that the software on top is the same.
87.
by pjdesno 1y ago
Oh, and no one has a solution to make HDDs faster. If anything, they may have gotten slower as they get optimized for capacity instead of speed. (Well, peak data transfer rate keeps going up as bits get packed tighter, but capacity goes up
88.
by pjdesno 1y ago
Flash went from within 2x the price of DRAM in 2012 or so to maybe 40-50x cheaper today, driven somewhat by shrinking feature sizes, but mostly by the shift from SLC (1 bit/cell) to TLC (3 bits) and QLC (4 bits) and from planar to 300+
89.
by pjdesno 1y ago
See comments above about AWS per-request cost - if your customers want higher performance, they'll pay enough to let AWS waste some of that space and earn a profit on it.
90.
by pjdesno 1y ago
LIST is dog slow, and everyone expects it to be. (my research group did a prototype of an ultra-high-speed S3-compatible system, and it really helps not needing to list things quickly)

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