Time Machine backup size seems to be too small

It is my understanding that Time Machine does not compress as it backs up and that it backs up everything (at least in default mode).

Why then is the space-used stat given by Finder re my external hard drive to which I backed up my iMac’s (OS X 10.9.5) internal drive much lower/less than the same stat in re my internal drive from which I backed up. The difference is 354.39 GB on internal vs. 85.83 GB on external.

My first backup took only about 40 minutes, which surprises me – thought would be like 4 hours, so I am wondering if it was complete and successful. However, all the files on my internal do seem to be on the external, and I got not messages indicating that there was a problem. It has been backing up hourly since that initial backup without any problems apparently.

Shouldn’t those stats be the same?

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scp file from machine A to machine with no password prompt and copy same file to different location

I am trying to write a shell script through which i want to copy file from machineA to machine B.I have already setup passwordless connection .In the machine B again the samefile i want to copy to different path in the which
the directory is owned by different user. How can I achive this


  1. Machine A

    scp /home/user/txt user@xhost/home/user/txt
  2. Machine B

    It simply copies the file without asking password under home directory


    I again want to copy the same file into diffrent location i get permission denied:

    cp /home/user/txt /apps/java/software/    # (permission denied)

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Python – window size for machine learning model

i am working on a python task using logistic regression classifier and i am trying to set w window size for the input data before the fitting step. here is what i have tried

from itertools import islice
def window(seq, n=2):
    "Returns a sliding window (of width n) over data from the iterable"
    "   s -> (s0,s1,...s[n-1]), (s1,s2,...,sn), ...                   "
    it = iter(seq)
    result = tuple(islice(it, n))
    if len(result) == n:
        yield result
    for elem in it:
        result = result[1:] + (elem,)
        yield result

x_train = list(window(x_train))
y_train = list(window(y_train))
x_test = list(window(x_test))
y_test = list(window(y_test))
seed = 42
##LogisticRegressionCV Classifier
lr = LogisticRegression()

kfold = KFold(n_splits=10, random_state=seed)
results = cross_val_score(lr, x_train, y_train, cv=kfold)

here is i have used a function to apply a window size = 2 but in the fitting step the following error appears

ValueError: Found array with dim 3. Estimator expected <= 2.

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DNS lookups on my Ubuntu 16.04 machine have suddenly started returning for everything, intermittently. Why?

DNS lookups on my Ubuntu 16.04 LTS workstation has recently gone crazy, and I don’t know why. Every now and then it will start returning for just about anything. For example, a few minutes ago, dig www.google.com said:

; <<>> DiG 9.10.3-P4-Ubuntu <<>> www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15032
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;www.google.com.            IN  A

www.google.com.     0   IN  A

;; Query time: 0 msec
;; WHEN: Wed Jun 28 15:53:35 PDT 2017
;; MSG SIZE  rcvd: 48

A few minutes later it started behaving normally again:

; <<>> DiG 9.10.3-P4-Ubuntu <<>> www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50042
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

; EDNS: version: 0, flags:; udp: 4096
;www.google.com.            IN  A

www.google.com.     122 IN  A

;; Query time: 0 msec
;; WHEN: Wed Jun 28 15:55:11 PDT 2017
;; MSG SIZE  rcvd: 59

It's flip-flopped a few times in the last several hours. I can't think of any changes I made that could have triggered this behavior.

Note that there is no on my LAN. (it's all 192.168.0.x.)

I have tried rebooting my Ubuntu box and all of my network equipment and also changing the Network Connections >> IPv4 Settings >> Method to "Automatic (DHCP) addresses only", and manually setting DNS to, but It still sporadically switches to returning

How do I debug (and fix) this issue?

Other info:

$ ls -al /etc/resolv.conf
lrwxrwxrwx 1 root root 29 Oct 24  2016 /etc/resolv.conf -> ../run/resolvconf/resolv.conf

$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)


I just discovered that when this happens, my router's admin page is complaining that "Your ISP's DHCP does not function properly". I found a forum posting that mentioned that some ISPs apparently refuse to respond to new DHCPs requests, resulting in this error. I'd had some power outages recently (and also had to unplug some equipment when a UPS died), so I'm guessing these were related to this issue. It also seems that any time my router reboots (which is happens after practically any config change) there's about a 50% chance I'll get this error.

I'm still not sure where the address is coming from. It turns out that even if I tell dig which DNS server to use when my router is borked it'll return

# dig @ www.yahoo.com

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @ www.yahoo.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35485
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;www.yahoo.com.         IN  A

www.yahoo.com.      0   IN  A

;; Query time: 0 msec
;; WHEN: Thu Jun 29 11:10:14 PDT 2017
;; MSG SIZE  rcvd: 47

I suspect that either my router or my ISP is intercepting outgoing DNS queries requests and returning these bogus responses, but I don't know how to confirm this.

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Non Scalable Machine learning model

Watching tutorials about Naive Bayes Multinomial classifier, it is stated that it is a scalable model. For curiosity,which machine learning models are not scalable?

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Problem connecting pi b+3 model with ethernet cable on a windows machine

I’ve read multiple guides on how to connect a raspberry pi with a pc through internet yet I always fail . I have a windows machine,I did share the wifi connection with the ethernet which the pi is connected to. I also did activate ssh from the sudo raspi-config menu beforehand (but did not add an ssh file) on the pi. I also read the pi’s ip using the advanced ip scanner program yet I cannot connect on the pi. Both Putty and VNC viewer say “network refused” whenever I try to connect. And yes I did consider restarting the machine multiple times to ensure sharing is applied.
I tried the exact same steps on another machine on another network and got the same problem. Can anyone give me a hint? I’m getting kinda desperate.Thanks for your time. I’ll post an answer if I find one.

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What to look for in a good beginner’s sewing machine?

I’ve been thinking about learning to sew and would like to get to the point where I could possibly make a dress (and try to invent one with pockets). I’ve repaired buttons and rips by hand but guess that won’t cut it for anything bigger to start off in getting started I need a sewing machine.

I don’t want to spend too much to start but don’t want something that the lack of quality makes life difficult in it self. Also with the machine what else would bee needed (other than fabric)?

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Virtual machine using VirtualBox or VMWare [on hold]

I intend to share 1 pc using virtualization on fedora 28 as host os and ubuntu as guest os.

My earlier question was too broad, so the options viable for me are VirtualBox or VMWare for sharing 1 pc between 2 users so that they work independently.

Problem: The guest os should completely capture one of the two mice while letting the other mouse be detected by the host os.


  1. VMWare Player: After installation on fedora 28 as host machine this gives me I/O warning : failed to load external entity "/etc/vmware/hostd/proxy.xml" when launched via terminal. How can i fix this?
    VMWare works as intended on Windows 10 as host and ubuntu as guest.

  2. VirtualBox: This solution works well as one of the two mice is captured by the guest os(ubuntu) and the other is free to use for host system. The only problem here is the mouse in the guest os is jerky and lags when the mouse motion starts. Any suggestions to fix this?

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Large 3D printer 10’x10’x4′ – Need G-code to tell when it stops extruding and to stop machine

We use Simplify and have a large 10’x10’x4’ printer. We need G-code that when the extrusion stops the machine will stop and raise 10 mm as to not to burn the print, so we know where the extrusion stopped.

We are using beads instead of filament, which work great. We have a mechanical pusher of beads that once it stops spinning, we need a G-code to recognize it is not spinning anymore and to stop the printer at that point and to lift up 10 mm. Printer might go 3-4 days sometimes a week with no problems and all of a sudden no extrusion and machine keeps thinking its printing. We have to start all over.

Any suggestions?

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Finding all storage devices attached to a Linux machine

I have a need to find all of the writable storage devices attached to a given machine, whether or not they are mounted.

The dopey way to do this would be to try every entry in /dev that corresponds to a writable devices (hd* and sd*).

Is there a better solution, or should I stick with this one?

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