pjdesno

13 ms·

121.
by pjdesno 2y ago
I work with storage, and "how long does it take" questions come up a lot - filling an HDD, wearing out an SSD, etc. A day is about 10^5 seconds. 10^6 seconds is about a fortnight. A year is about 10^4 hours, or 3 10^7 seconds, so
122.
by pjdesno 2y ago
I was at the Toronto IETF meeting in 1994(?) when they voted on 8-byte vs 16-byte addresses. I share the author's suspicion that 8-byte addresses would have made a world of difference in IPv6 adoption. It's hard to understand nowa
123.
by pjdesno 2y ago
Does the UI still suck?
124.
by pjdesno 2y ago
Note that this will probably cause branch prediction misses, just like thread switching does - modern CPUs have a return address predictor which is just a simple stack. I don’t think you can avoid this without compiler support.
125.
by pjdesno 2y ago
I love the term "superstition". I like to refer to lab "rituals" - if something works, repeat it, and never change things around "because it ought to work just as well". Life is too short to figure out all the
126.
by pjdesno 2y ago
I think it’s likely the latter, not the former. If they didn’t like coal ash they’d have voted for someone else.
127.
by pjdesno 2y ago
I reviewed it three times for different conferences :-) I’m still annoyed they didn’t include the drain time equation I used for calculating track width, which falls out of one of their equations. Oh, and I’m very glad you showed differing
128.
by pjdesno 2y ago
I love the visuals, and if it's ok with you will probably link them to my class material on block devices in a week or so. One small nit: > A typical random read can be performed in 1-3 milliseconds. Um, no. A 7200 RPM platter compl
129.
by pjdesno 2y ago
Sounds like they were generated by SCIgen.
130.
by pjdesno 2y ago
This would be great for civilian shipping in certain areas, as modern piracy seems to exclusively focus on holding crew members for ransom. Lots of comments here raise good questions about its fitness as a military vessel, but maybe the poi
131.
by pjdesno 2y ago
Seems like wishful thinking, much like saying engineers at Amazon can do whatever they want despite what Bezos says. Yes, they can , but they'd get fired. And yes, incentives could be changed, but they won't, because the person
132.
by pjdesno 2y ago
Perhaps relevant to a lot of HN readers - the culture of conference publishing in much of CS (I'm in computer systems myself) seems to result in significantly different dynamics. Journal papers are single-blind, i.e. the reviewers know
133.
by pjdesno 2y ago
Those copper wires ran from your house to the local central office, the "last mile" of the connection. (which was sometimes 2-3 miles long) A quick read of the linked article seems to indicate that it's BS, as it doesn't
134.
by pjdesno 2y ago
There are a couple of generations of filesystems in between FFS and ZFS. And for modern filesystems it's also worth looking at btrfs, Microsoft's Resilient File System, and Apple APFS. Also note that ext2 is basically a re-impleme
135.
by pjdesno 2y ago
Note that there are some significant non-Unix filesystems along the way. In particular, a few years later: "Reimplementing the Cedar File System Using Logging and Group Commit", Robert Hagmann, Xerox PARC. SIGOPS Operating Systems
136.
by pjdesno 2y ago
Yes, I believe so. You can't expect dialing to work until you've received dial tone, and with older equipment [on the phone company side] there might be a significant delay.
137.
by pjdesno 2y ago
Cool! I was an intern with the modem folks at Motorola Codex back in the 80s; I probably worked with some of the folks who did the data path on that one. (hmm, actually by that time it's likely that all the Codex tech had been killed,
138.
by pjdesno 2y ago
It might be trying to detect dial tone, then hanging up and trying again after a second or so - the click would be the mechanical relay you see in the schematic. (note that standard phone lines don't send dial tone until they detect an
139.
by pjdesno 2y ago
Here's 1gbit running over 8 strands of barbed wire: https://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm
140.
by pjdesno 2y ago
See https://hackaday.com/2024/11/19/dial-up-internet-using-the-v... for a description of a telephone line simulator.
141.
by pjdesno 2y ago
I'm surprised that you could get a modem pair to connect with a plain wire. An old dial telephone (e.g. a 500 set) was an entirely passive device, relying on power from the central office end of the wire. The carbon mic didn't nee
142.
by pjdesno 2y ago
I’ve been pretty happy with my EcoTank, but my favorite is still the HP PageWide I have at work. (I typically have to print ~100 5-10 page exams twice a semester) I’m very sad they discontinued them.
143.
by pjdesno 2y ago
Note that existing bandwidth usage has been driven by digitization of existing media formats, for which there was already a technology and industry - first print, then print+images, then audio, then video. People have been producing HD-qual
144.
by pjdesno 2y ago
ps: the white paper is old, I think head heights were 2nm back then. I'm pretty sure <1nm requires helium-filled drives, as the diameter of a nitrogen molecule is about 0.3nm
145.
by pjdesno 2y ago
Um, no. Not unless you're still running ancient sub-1TB enterprise drives. It turns out that modern hard drives have a specified workload limit [1] - this is an artifact of heads being positioned at a low height (<1nm) over the plat
146.
by pjdesno 2y ago
I've been looking for something to give to the students in my 3rd-year undergrad course. I had high hopes when saw the title, but this isn't it - it's immense and I don't think anyone will read it. However I'm serio
147.
by pjdesno 2y ago
Like most HN readers I'm in computer science, but I do academic research so I review papers - not a lot, but probably 20-25 a year, sometimes more. I get paid nothing to do this - it's considered "service", i.e. it'
148.
by pjdesno 2y ago
I've always thought that there ought to be a way to create an investment fund specializing in East Coast ski resorts, Florida homeowners insurance, and other investments that are getting hammered by climate change, and advertise it on
149.
by pjdesno 2y ago
Note that "in the 80s" in the article seems to refer to the late 80s - CMOS was kind of rare in the earlier 80s, when IIRC most things were TTL or NMOS.
150.
by pjdesno 2y ago
Old Lyme resident here, high school class of 82 - it was the younger siblings of my classmates who were getting "Lyme arthritis" starting in the late 70s or maybe 1980. Like most of the populated Northeast, most the area was clear

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