pjdesno

11 ms·

91.
by pjdesno 1y ago
The only scholarly paper they've written about it is this one: https://www.amazon.science/publications/using-lightweight-fo... (well, I think they may have submitted one or two others, but this is the only one tha
92.
by pjdesno 1y ago
Ceph's S3 protocol implementation is really good. Getting Ceph erasure coding set up properly on a big hard disk pool is a pain - you can tell that EC was shoehorned into a system that was totally designed around triple replication.
93.
by pjdesno 1y ago
Google for Seagate Mozaic
94.
by pjdesno 1y ago
Repeating a comment I made above - for standard tier, requests are expensive enough that it's cost-effective to let space on the disks go unused if someone wants an IOPS/TB ratio that's higher than what disk drives can provid
95.
by pjdesno 1y ago
Full seek on a modern drive is a lot closer to 25ms than 8ms. It's pretty easy to test yourself if you have a hard drive in your machine and root access - fire up fio with --readonly and feed it a handmade trace that alternates reading
96.
by pjdesno 1y ago
Note that you can kind of infer that S3 is still using hard drives for their basic service by looking at pricing and calculating the IOPS rate that doubles the cost per GB per month. S3 GET and PUT requests are sufficiently expensive that A
97.
by pjdesno 1y ago
Most tutorials aren’t for non-developers. They’re not for developers, either. They’re a bunch of prose I want to skip, and then I finally get to the steps I’m really looking for, but the author left one out, or assumed some weird developmen
98.
by pjdesno 1y ago
At some point the rest of us have to stop paying for people's stupid behavior. US taxpayers have funneled untold billions of dollars into these states to prop up their real estate industry by providing FEMA flood insurance at hugely su
99.
by pjdesno 1y ago
Note that this is very early work - one of the papers (the HUST one from this June) shows an 8x8 cell device, i.e. 64 bits in SLC mode. DRAM kind of plateaued in 2011, when it hit $4/GB; since then it's gotten faster and bigger, b
100.
by pjdesno 1y ago
Related to this, I remember seeing a research talk that fairly convincingly demonstrated that almost all performance differences between several ARM amd x86 CPUs were explained by microarchitectural features (branch predictor type and size,
101.
by pjdesno 1y ago
Relevant to this: memory cost per GB dropped exponentially every year from the days of the earliest computers until 2010 or so, reaching $4/GB in 2011. A decade and a half later it's still in the $2-$4/GB range. Note also tha
102.
by pjdesno 1y ago
I worked for 5 startups before I went back to grad school and then entered academia; it was over a quarter century ago but I think some of the lessons remain valid. The best startup I was at was one where four engineers who knew each other
103.
by pjdesno 1y ago
One of the Japanese sites has a list of SSDs that people have observed the problem on - most of them seem to be dramless, especially if "Phison PS5012-E12" is an error. (PS5012-E12S is the dramless version) Then again, I think dra
104.
by pjdesno 1y ago
The FTL executes on the SSD controller, which (on a DRAM-less controller) has limited on-chip SRAM and no DRAM. In contrast, a controller for more expensive SSDs which will require an external on-SSD DRAM chip of 1+GB. The FTL algorithm sti
105.
by pjdesno 1y ago
In theory data center cooling is simple - CPUs run at 60-70C, while the outside ambient is usually 30C or less, so heat should just "flow downhill" with a bit of help from fans, pumps, etc. The problem with using air cooling to ge
106.
by pjdesno 1y ago
It appears to be about as efficient as a pumped storage hydro facility (e.g. here's one in Massachusetts, built in 1970 or so - https://en.wikipedia.org/wiki/Bear_Swamp_Hydroelectric_Power... ) A gas-based design s
107.
by pjdesno 1y ago
This paper argues that electronic locks played a large role: https://link.springer.com/article/10.1057/s41284-024-00452-2 I would bet that the pervasive use of electronic records has something to do with it, too.
108.
by pjdesno 1y ago
The strip came out in 1995, at the peak of the minivan boom, with around 1.3M units sold that year.
109.
by pjdesno 1y ago
It's not just law enforcement and sentencing - there are verifiable numbers for the results of certain crimes - homicides and auto theft come to mind - and most have declined precipitously. E.g. Boston had 1,575 reports of auto theft i
110.
by pjdesno 1y ago
Kind of relevant to this is the NTSB analysis of a self-driving crash in 2017: https://www.ntsb.gov/investigations/accidentreports/reports/... Basically a truck was backing up into an alley - it was at an ang
111.
by pjdesno 1y ago
My take on it - performance decays when engineering management doesn’t prioritize it. Modern example: Laptops boot in seconds. My servers take about 5 minutes to get to Linux boot, with long stretches of time taken by various subsystems, wh
112.
by pjdesno 2y ago
Navarro is still a professor emeritus at UC Irvine. That's just an honorary title, and at most places can be revoked for sufficient damage to the university's reputation. This would seem to be the case, especially because at least
113.
by pjdesno 2y ago
Frankly it sounds like someone who voted for Trump and wants to avoid having people criticize him for it, dressing up his "stop picking on me" schtick with pseudo-intellectual rationalizations. You can't ignore politics when
114.
by pjdesno 2y ago
I'm not sure why one would compare reviews by acknowledged experts in a field with stuff written by anonymous randos, and it seems highly unlikely that anyone with the appropriate qualifications would be lurking on some mechanical turk
115.
by pjdesno 2y ago
Someone I know who went to Berklee in the early 90s said that it was a required text for certain jazz classes, and you had to buy it from a bootlegger.
116.
by pjdesno 2y ago
"likely" -> "certainly". At the time the band was formed, the Gang of Four was in the news because they were being brought to trial in China. About the only GoF song that wasn't extremely political was their one
117.
by pjdesno 2y ago
Do you mean the RDMA verbs API? Or something else? I'll point out that it's an API, so an implementation pattern isn't relevant. (it's also an awfully obscure one, and I say that as someone who was involved in standardiz
118.
by pjdesno 2y ago
I didn't read the GoF book until the early 2000s. I gave up on it after reading their recommendation to use the "state machine pattern" for network protocols- that was a popular approach in the late 70s and early 80s, but by
119.
by pjdesno 2y ago
It was a bowling alley across from the Cala Market when I lived there. Unfortunately the market didn't morph into something anywhere near as cool - it's a Whole Foods now :-(
120.
by pjdesno 2y ago
I'd have to go back and look through back issues of the New London Day to get any details, but having grown up in the area (graduated high school in '82) I seem to recall that he may have stayed in his position for a number of yea

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