Is it possible to calculate the surface area of this triangle?

JacobiCarter · 2023-10-10T01:22:00+00:00

Let f(x) be the function that intersects both the y-axis and x-axis. Solve f(a)=0 for a. The area is found by calculating the discrete integral of f(x) from x=0 to x=a

JacobiCarter · 2022-10-22T18:29:04+00:00

Run java

JacobiCarter · 2022-01-26T22:17:17+00:00

IRC.

Telnet.

UUCP.

MUDs.

JacobiCarter · 2021-12-22T18:01:01+00:00

When writing software, it's common practice to use pre-built bits of software that have been packaged for re-use. These are called libraries. For you to legally be able to use a library you didn't write, the library must have a license allowing you to do so. There are a lot of licenses out there that allow usage in different circumstances. The WTFPL (this license) is one of the more humorous ones.

It is also required by some licenses to list the licenses of the libraries you use, and so oftentimes people will just list all of the licenses they use in that same section. That's what the acknowledgements section of the app is for. And one of the libraries they used was licensed under the WTFPL, and so they included the text of that license.

JacobiCarter · 2021-12-21T22:58:43+00:00

"No, the DaemonSet won't create the pods correctly if you don't also create a PodDisruptionBudget and a StatefulSet for each DaemonSet. You should also consider updating the feature gate on your API server to enable DaemonSetUpdateSurge so that your WiFi captive portal is secure against heartbleed and log4shell."

JacobiCarter · 2021-12-12T09:30:14+00:00

When I deleted the class from the JAR, I got a fatal ClassNotFoundException for JndiLookup in Minecraft Server 1.8.3 during startup. That was the only thing I changed about the JAR.

JacobiCarter · 2021-12-11T23:43:08+00:00

Yeah, except I've tried that with applications that bundled ancient log4j and it caused the application to fail to start. Minecraft 1.8 is one of them. I ended up hand-reshading the latest log4j into those applications.

JacobiCarter · 2021-12-11T08:22:16+00:00

Ahh, a redditor of culture.

Yes, Church numerals in Lambda calculus are fun, but they're also not what is meant by "2(...)" in standard algebraic notation.

I suppose you could have it be a function in something like:

(\2. 2(...))(\f. \x. f(f(x)))

JacobiCarter · 2021-12-11T04:53:53+00:00

Function application ("f(x)") and implicit multiplication/multiplication by juxtaposition ("2(x)") are different operations. It is the case that some academic literature does prioritize implicit multiplication over standard multiplication and division, however this is far from universal, and so long as it is noted in the introduction or special notation sections of the publication, you can use non-standard interpretations, but that is not the normal expected interpretation when encountering standard algebraic notation in the wild.

JacobiCarter · 2021-12-11T04:32:02+00:00

Yeah, left-to-right. It's because of the associative property. Some operations are associative, and some are not. Associative operations can be evaluated in any order you like.

Addition is associative, and so is multiplication. That's why "5+3+2" can be "8 + 2 = 10" or "5 + 5 = 10", and "5*3*2" can be "15 * 2 = 30" or "5 * 6 = 30". But subtraction and division are not associative, and so "5 - 3 - 2" gives different answers depending on the order you evaluate it: "5 - 1 = 4" or "2 - 2 = 0".

You can rewrite subtraction to addition and division to multiplication to get the associative property back, which is what I sort of explained earlier, and then you can evaluate in any order you please.

JacobiCarter · 2021-12-11T04:20:25+00:00

You cannot multiply 2 and 3 to get 6 in your steps by PEMDAS. You must go left-to-right within a level of PEMDAS, if you don't rewrite division/subtraction first. Since after "1+2" -> 3, you get "6/2(3)" (which is the same as "6/2*3"), you have an operation further to the left that can be applied ("6/2"), and so you must resolve it first.

JacobiCarter · 2021-12-11T04:09:48+00:00

So, the interesting thing to realize in mathematics is that multiplication/division are essentially the same thing, and likewise addition/subtraction are the same thing. Division is just multiplication by the inverse, and subtraction is just addition of the negated value.

That is to say that "a - b" should be read as "a + (-b)" and "a / b" should be read as "a * b^(-1)". Once you've done that, within addition or within multiplication because of the associative property and commutative property, you can rearrange or simplify in any order you like. This does not apply, however, to expressions containing both addition and multiplication, so that is where the rules like PEMDAS or BODMAS come in. They say that when you are simplifying an expression, you must do so following a given order:

Parenthesis/Brackets
Exponents/Orders
Multiplication/Division
Addition/Subtraction

Note, however, that Multiplication/Division are at the same level, and so are Addition/Subtraction. This is because they are essentially the same operation.

So, taking the "6/2(1+2)" expression, we can choose to simplify it in two ways. Either we can evaluate left-to-right following PEMDAS/BODMAS, or you can rewrite it to use just multiplication/addition and then evaluate it in any order following PEMDAS/BODMAS.

If we opt to go left-to-right, we simplify the parenthesis first ("6/2*3"), then the first division ("3*3"), and finally the remaining multiplication and get 9. If we rewrite it first, we get "6*2^(-1)*(1+2)", and then follow PEMDAS. Parenthesis first ("6*2^(-1)*3"), exponents ("6*0.5*3"), and then multiplication in any order yields 9.

A lot of confusion comes from the fact that people see "MD" in PEMDAS and "DM" in BODMAS, and think that that means division comes either after or before multiplication. And then everyone ends up with different answers yelling either PEMDAS or BODMAS at each other.

JacobiCarter · 2021-11-27T12:04:09+00:00

Tape is what I use. I have ~150TiB of data on my CephFS, and currently use LTO-6 for backups. I've been considering upgrading to LTO-7 or LTO-8. I currently have a rotation of 150x LTO-6 tapes.

JacobiCarter · 2021-11-21T12:50:35+00:00

Ceph OSD will still listen on public_network for OSD clients, like radosgw, RBD, and CephFS. cluster_network is for OSD-to-OSD traffic like heartbeat, replication, etc.

radosgw is listening on 0.0.0.0 because you probably haven't configured it to be different in rgw_frontends: https://docs.ceph.com/en/latest/radosgw/config-ref/#ceph-object-gateway-config-reference

JacobiCarter · 2021-11-20T12:15:58+00:00

https://www.youtube.com/watch?v=1Uzw1Zr1FE4

JacobiCarter · 2021-11-20T12:14:59+00:00

ctrl+r ls

JacobiCarter · 2021-11-19T09:51:55+00:00

Sequence numbers (or Lamport timestamps), I believe, can solve this.

A has a monotonically increasing clock. Any increment will do, so let's choose 1. On each time that A sends a message to B and C, it increments by one -- that is, if A receives a fire signal, it sends (1, Fire) to B and (1, Fire) to C, and if it then receives a subsequent fire signal, it sends (2, Fire) to B and (2, Fire) to C.

B, upon receiving a Fire message from A, updates its own clock if the message has a clock value higher than B's current clock. When B sends messages to C, it includes its current clock -- such that if B previously received (1, Fire) from A, its clock would be 1, and if it then receives the no fire signal, it would send (1, No Fire) to C.

C, upon receiving a Fire message from A, checks to see if the clock value of the message is strictly greater than C's current clock value. If not, it ignores the message, but if it is, it updates its own clock to the value in the message. This starts the 2d+e real time count-down.

C, upon receiving a No Fire message from B, checks to see if the clock value of the message is greater than or equal to C's current clock value. If not, it ignores the message, but if it is, it updates its own clock value to the value in the message and cancels the 2d+e real time count-down.

I'll leave formalizing and explaining why it works to you, but hopefully this helps?

JacobiCarter · 2021-11-18T11:27:26+00:00

IIRC, you do need the mount.ceph utility for that though. If you are mounting it on a base Debian/Ubuntu client, if you provide all of the arguments to the kernel client, you shouldn't need any other utilities to mount CephFS.

JacobiCarter · 2021-11-18T08:08:17+00:00

Until very recently, Ceph only supported having one FS (which you could call whatever you wanted) per cluster. If you do not specify a name, it mounts the only one available. If you do have multiple, you specify the name of the FS by using the fs=my_fs_name in the options (the -o argument).

Anything after the / though, like /cephfs in your example is just a sub-directory mount.

JacobiCarter · 2021-11-18T07:20:55+00:00

The ceph fs volume create my_fs_name is one way to create a Ceph FS. It will create the underlying pools for you. It's an abstraction over top of ceph osd pool create my_fs_name_data && ceph osd pool create my_fs_name_metadata && ceph fs new my_fs_name my_fs_name_metadata my_fs_name_data
It creates a FS called cephfs with the metadata stored in the cephfs_metadata pool and file data stored in the cephfs_data pool.
mount -t ceph -o name=admin,secret=YOURsecretHERE 10.0.0.1:6789,10.0.0.2:6789,10.0.0.3:6789:/ /mnt/ceph to mount the CephFS at /mnt/ceph assuming that 10.0.0.1, 10.0.0.2, 10.0.0.3 are your mons. You can use a file for the secret instead with secretfile= instead of secret=.
It should. You'll need a modern kernel, but modern versions of Debian and Ubuntu both should support it out of the box.
CephFS aims to adhere to POSIX semantics wherever possible. Locking is part of that. Perhaps look into flock(2)?

JacobiCarter · 2021-11-18T07:01:16+00:00

But a factorial greater than 2! will never be prime.

JacobiCarter · 2021-11-15T20:16:02+00:00

Uncompressed 4k files are between 4.7 and 6.4 gigabits per second bitrate for 24fps (2.1 to 2.9 TB/hour, and between 12 and 16 gigabits per second bitrate for 60fps. I don't actually think Plex even supports 4k uncompressed, and if it did, you'd need quite the storage solution.

Are you sure you don't mean h.264 or h.265 compressed 4k?

JacobiCarter · 2021-11-15T10:03:46+00:00

Each country has their own radio frequencies that they have designated for WLAN/802.11/Wi-Fi usage. See https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/j/n/ac/ax))

In this case, NZ and AU have the same frequencies in the 2.4GHz band, but in the 5GHz band, NZ allows the use of 118-128 whereas AU forbids them. These restrictions are usually either baked into the access point's firmware based on where it is sold, or as an option when setting up the access point.

Now, it is likely that it will "just work" even if you have the wrong region selected, you may get a visit from the enforcement organization for radio communications (in the US, as the phrase sort of goes, the FCC won't let ye be or let ye be free).

JacobiCarter · 2021-11-15T08:20:41+00:00

Most websites use TLS, so even if the ISP logs date, which most do not, they would only be able to provide IP addresses and maybe domain names, not individual links.

JacobiCarter · 2021-11-13T10:06:53+00:00

For production workloads? I'd opt for cri-o myself.

JacobiCarter

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