Can a website detect remote operation of a computer?

Sorry if this is a dumb question, but I am not very educated when it comes to security.

I was wondering if a website I am visiting can detect whether or not the computer that is being used is being operated remotely.

For example…

I have two desktops. I use Desktop 1 to remotely operate Desktop 2 through windows’ Remote Desktop Connection. Through this connection, I visit a website on Desktop 2. Would it be possible for the website to detect the fact that Desktop 2 is being remotely operated? (Not detect Desktop 1, but just detect remote operation in general).

Thank you

Given an array arr[] of N integers. Do the following operation n-1 times

For every Kth operation: Right rotate the array clockwise by 1. Delete the (n-k+1)th last element.

eg:

A = {1, 2, 3, 4, 5, 6}. Rotate the array clockwise i.e. after rotation the array A = {6, 1, 2, 3, 4, 5} and delete the last element that is {5} so A = {6, 1, 2, 3, 4}. Again rotate the array for the second time and deletes the second last element that is {2} so A = {4, 6, 1, 3}, doing these steps when he reaches 4th time, 4th last element does not exists so he deletes 1st element ie {1} so A={3, 6}. So continuing this procedure the last element in A is {3}, so outputp will be 3

How to solve this?

sequence of insert and delete operation in (2,3)-tree

I need help by understanding a theorem and its proof from a script. It says “There is a sequence of $ n$ insert and delete operations in a (2,3)-tree that require $ \Omega ($ n log n$ )$ many split and merge operations.”

I actually have no idea how such a sequence looks like. I have tried to perform some insert and delete operations on a (2,3)-tree and I got different results on split and merge operations but I think there is a “special” sequence to maximize the split and merge operations.

I would be very grateful if someone can help me with this issue, so I can try to see how the proof of the theorem can be done.

Greetings

Does canceling update operation perform automatic rollback

I ran into a bit of confusion. I’m under the belief that database operations are automatic – that is either the query succeeds or the transaction is automatically rolledback. For example – if you have a long running UPDATE statement and you “cancel” it before it finishes – IE clicking red circle X button in SQL Developer (which you should receive a ORA-01013: user requested cancel of current operation error). Upon canceling the query the query is rolled back and no rows were affected. I believe the same should hold true for DELETE statements.

I looked around for some documentation on it and I found this article that really isn’t authoritative.

How can I restore DVD drive operation following recent Ubuntu r10.04 `apt upgrade`

Some time in the last day or two, following one of the recent apt update-s the DVD driver on my desktop has stopped working.

  • between: 2019-09-15 (UTC) or so
  • until: 2019-09-20 (UTC)

After several unsuccessful attempts to understand what happened, I have backtracked a few steps and decided what I need to do ‘work forward from here‘ and restore the DVD and replay operations.

Here’s my thinking:

  • The player should work (it can work)
    • I did work prior to what ever has changed in the software.
  • By restoring function, not only will I learn something about that kind of thing, it may help others get past this kind of issue.
    • I have seen earlier problems back with Ubunty 14 and 16 that look similar on stackoverflow/askubntu.
  • What ever has happened looks very largely like a regression
    • Nothing has changed in the drive or hardware itself.
    • And the ‘target’ DVD I chose is one that played fine 8 or 9 days ago.
  • If I need to back-out a package or update, so be it. The best way to findout what it is is to identify today’s problem.

Symptoms

My layman’s view of the problem is that for some reason applications cannot read the DVD content. dvdbackup for example reported that ti cannot find titles. Handbrake and handbrakeCLI have similar issues. They try to read but the interpretation is unintelligible.

Same with VLC no doubt as it just ties and tries and displays a black screen — Nothing happens. There are reports of scrambled cells and I/O errors.

You might think a DVD is corrupt. That’s why I picked one I viewed successfully in the recent past.

My aim is to look at what I’d do with a new DVD drive installed.

  • What steps would I follow to get a new DVD working?
  • What installation errors and problems are showing up now?
  • To resolve them if that’s practical / feasible.
    • Back out a package or ammeliorate things with alternative or supporting packages that may be not-yet-delivered/installed.

I hope you can help. Here is the delta between a “before” and “now” scenario where I did a domestic reset and had a cup of tea.

I don’t know if the dmesg people read these questions, but I’d very much prefer it if dmesg output showed the local time so I have a better idea of what is happening and where that was on the time line. Looking forward to your insights.

Delta experiment …

What do we know?

Tonight …

  1. I took down a Harry Potter DVD that has played on this PC before (some time last week actually).
    • The result is that VLC just shuffles a bit and gives up.
  2. So then unloaded the DVD
  3. Ran dmesg > tmp.01
    • to get the “baseline”
  4. Reloaded the DVD into the drive
  5. Used the VLC “Play disk” Media menu option
  6. Allowed the DVD player shuffle and grunt
  7. Once that’s done, ran dmesg > tmp.02 again.
  8. took a delta (with diff) as shown

I apologise for pasting so much here. I am not clear on what’s important and what is just a repeats of the same errors.

dmesg delta

[60610.254451] scsi_io_completion_action: 2 callbacks suppressed [60610.254457] sr 1:0:0:0: [sr0] tag#4 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.254460] sr 1:0:0:0: [sr0] tag#4 Sense Key : Illegal Request [current]  [60610.254463] sr 1:0:0:0: [sr0] tag#4 Add. Sense: Read of scrambled sector without authentication [60610.254465] sr 1:0:0:0: [sr0] tag#4 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.254467] print_req_error: 2 callbacks suppressed [60610.254468] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.254473] buffer_io_error: 2 callbacks suppressed [60610.254474] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.302074] sr 1:0:0:0: [sr0] tag#14 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.302077] sr 1:0:0:0: [sr0] tag#14 Sense Key : Illegal Request [current]  [60610.302080] sr 1:0:0:0: [sr0] tag#14 Add. Sense: Read of scrambled sector without authentication [60610.302082] sr 1:0:0:0: [sr0] tag#14 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.302084] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.302087] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.338005] sr 1:0:0:0: [sr0] tag#5 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.338008] sr 1:0:0:0: [sr0] tag#5 Sense Key : Illegal Request [current]  [60610.338011] sr 1:0:0:0: [sr0] tag#5 Add. Sense: Read of scrambled sector without authentication [60610.338014] sr 1:0:0:0: [sr0] tag#5 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.338015] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.338019] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.373951] sr 1:0:0:0: [sr0] tag#15 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.373954] sr 1:0:0:0: [sr0] tag#15 Sense Key : Illegal Request [current]  [60610.373957] sr 1:0:0:0: [sr0] tag#15 Add. Sense: Read of scrambled sector without authentication [60610.373959] sr 1:0:0:0: [sr0] tag#15 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.373961] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.373964] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.406292] sr 1:0:0:0: [sr0] tag#16 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.406295] sr 1:0:0:0: [sr0] tag#16 Sense Key : Illegal Request [current]  [60610.406298] sr 1:0:0:0: [sr0] tag#16 Add. Sense: Read of scrambled sector without authentication [60610.406301] sr 1:0:0:0: [sr0] tag#16 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.406302] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.406305] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.441955] sr 1:0:0:0: [sr0] tag#17 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.441957] sr 1:0:0:0: [sr0] tag#17 Sense Key : Illegal Request [current]  [60610.441961] sr 1:0:0:0: [sr0] tag#17 Add. Sense: Read of scrambled sector without authentication [60610.441963] sr 1:0:0:0: [sr0] tag#17 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.441965] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.441968] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.473961] sr 1:0:0:0: [sr0] tag#18 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.473964] sr 1:0:0:0: [sr0] tag#18 Sense Key : Illegal Request [current]  [60610.473967] sr 1:0:0:0: [sr0] tag#18 Add. Sense: Read of scrambled sector without authentication [60610.473969] sr 1:0:0:0: [sr0] tag#18 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.473971] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.473974] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.505948] sr 1:0:0:0: [sr0] tag#19 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.505951] sr 1:0:0:0: [sr0] tag#19 Sense Key : Illegal Request [current]  [60610.505954] sr 1:0:0:0: [sr0] tag#19 Add. Sense: Read of scrambled sector without authentication [60610.505956] sr 1:0:0:0: [sr0] tag#19 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.505958] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.505961] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.534143] sr 1:0:0:0: [sr0] tag#20 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.534146] sr 1:0:0:0: [sr0] tag#20 Sense Key : Illegal Request [current]  [60610.534150] sr 1:0:0:0: [sr0] tag#20 Add. Sense: Read of scrambled sector without authentication [60610.534152] sr 1:0:0:0: [sr0] tag#20 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60610.534154] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60610.534157] Buffer I/O error on dev sr0, logical block 5960, async page read [60610.682399] sr 1:0:0:0: [sr0] tag#21 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60610.682403] sr 1:0:0:0: [sr0] tag#21 Sense Key : Illegal Request [current]  [60610.682406] sr 1:0:0:0: [sr0] tag#21 Add. Sense: Read of scrambled sector without authentication [60610.682409] sr 1:0:0:0: [sr0] tag#21 CDB: Read(10) 28 00 00 00 fa 35 00 00 01 00 [60610.682411] print_req_error: I/O error, dev sr0, sector 256212 flags 0 [60610.682416] Buffer I/O error on dev sr0, logical block 64053, async page read [60622.600135] scsi_io_completion_action: 2 callbacks suppressed [60622.600142] sr 1:0:0:0: [sr0] tag#9 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.600146] sr 1:0:0:0: [sr0] tag#9 Sense Key : Illegal Request [current]  [60622.600149] sr 1:0:0:0: [sr0] tag#9 Add. Sense: Read of scrambled sector without authentication [60622.600152] sr 1:0:0:0: [sr0] tag#9 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.600154] print_req_error: 2 callbacks suppressed [60622.600156] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.600161] buffer_io_error: 2 callbacks suppressed [60622.600162] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.632139] sr 1:0:0:0: [sr0] tag#21 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.632142] sr 1:0:0:0: [sr0] tag#21 Sense Key : Illegal Request [current]  [60622.632145] sr 1:0:0:0: [sr0] tag#21 Add. Sense: Read of scrambled sector without authentication [60622.632147] sr 1:0:0:0: [sr0] tag#21 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.632149] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.632152] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.664010] sr 1:0:0:0: [sr0] tag#23 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.664013] sr 1:0:0:0: [sr0] tag#23 Sense Key : Illegal Request [current]  [60622.664017] sr 1:0:0:0: [sr0] tag#23 Add. Sense: Read of scrambled sector without authentication [60622.664019] sr 1:0:0:0: [sr0] tag#23 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.664021] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.664026] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.696149] sr 1:0:0:0: [sr0] tag#31 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.696152] sr 1:0:0:0: [sr0] tag#31 Sense Key : Illegal Request [current]  [60622.696156] sr 1:0:0:0: [sr0] tag#31 Add. Sense: Read of scrambled sector without authentication [60622.696158] sr 1:0:0:0: [sr0] tag#31 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.696159] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.696163] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.728011] sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.728014] sr 1:0:0:0: [sr0] tag#0 Sense Key : Illegal Request [current]  [60622.728017] sr 1:0:0:0: [sr0] tag#0 Add. Sense: Read of scrambled sector without authentication [60622.728020] sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.728021] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.728025] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.768156] sr 1:0:0:0: [sr0] tag#1 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.768159] sr 1:0:0:0: [sr0] tag#1 Sense Key : Illegal Request [current]  [60622.768162] sr 1:0:0:0: [sr0] tag#1 Add. Sense: Read of scrambled sector without authentication [60622.768165] sr 1:0:0:0: [sr0] tag#1 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.768166] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.768170] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.800184] sr 1:0:0:0: [sr0] tag#2 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.800187] sr 1:0:0:0: [sr0] tag#2 Sense Key : Illegal Request [current]  [60622.800190] sr 1:0:0:0: [sr0] tag#2 Add. Sense: Read of scrambled sector without authentication [60622.800192] sr 1:0:0:0: [sr0] tag#2 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.800194] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.800198] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.832250] sr 1:0:0:0: [sr0] tag#3 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.832253] sr 1:0:0:0: [sr0] tag#3 Sense Key : Illegal Request [current]  [60622.832256] sr 1:0:0:0: [sr0] tag#3 Add. Sense: Read of scrambled sector without authentication [60622.832258] sr 1:0:0:0: [sr0] tag#3 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.832260] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.832264] Buffer I/O error on dev sr0, logical block 5960, async page read [60622.860376] sr 1:0:0:0: [sr0] tag#4 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60622.860379] sr 1:0:0:0: [sr0] tag#4 Sense Key : Illegal Request [current]  [60622.860383] sr 1:0:0:0: [sr0] tag#4 Add. Sense: Read of scrambled sector without authentication [60622.860385] sr 1:0:0:0: [sr0] tag#4 CDB: Read(10) 28 00 00 00 17 48 00 00 01 00 [60622.860386] print_req_error: I/O error, dev sr0, sector 23840 flags 0 [60622.860390] Buffer I/O error on dev sr0, logical block 5960, async page read [60623.004249] sr 1:0:0:0: [sr0] tag#5 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [60623.004252] sr 1:0:0:0: [sr0] tag#5 Sense Key : Illegal Request [current]  [60623.004256] sr 1:0:0:0: [sr0] tag#5 Add. Sense: Read of scrambled sector without authentication [60623.004258] sr 1:0:0:0: [sr0] tag#5 CDB: Read(10) 28 00 00 00 fa 35 00 00 01 00 [60623.004260] print_req_error: I/O error, dev sr0, sector 256212 flags 0 [60623.004265] Buffer I/O error on dev sr0, logical block 64053, async page read 

“Unable to access “Micro SD Card” – Not authorized to perform this operation

I have a micro SD card that I am trying to access to store documents. Currently running Ubuntu 16.04 on a Chromebook using Crouton. I’ve been trying every solution I can find, including formating the card to ext4. Regardless of my attempts, it still is saying “Unable to access” and “not authorized to perform operation”. Please let me know if you have any suggestions. Thank you!

Cannot Enable Livepatch on 18.04: “cannot send request … write operation not permitted.”

I installed Livepatch without incident, but when I tried to enable it I got this:

$   sudo canonical-livepatch enable [token redacted] [sudo] password for [redacted]:  2019/09/01 13:57:26 error executing enable: cannot enable machine: cannot send request: Post https://livepatch.canonical.com/api/machine-tokens: dial tcp: lookup livepatch.canonical.com on [::1]:53: write udp [fe80::466c:1448:d556:e7ce]:39080->[::1]:53: write: operation not permitted 

I don’t know how to decipher this. The reference to “dial tcp” is especially baffling. Is it not finding my internet connection (which is made through a USB-to-ethernet adapter)?