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1- Low quality or damaged wire

The most common reason for this is your cable, a charging cable that has higher resistance (worse thinner or damaged wire) will tell the phone to charge slower, reason for that is that your phone does not want to overwhelm a cable beyond it’s capacity and cause it to burn or even cause fires, but how does the phone know, well, ohm’s law will let it know, a voltage drop at the wire end once a load is attached (the charging is a load) tells it all it needs to know. then the phone can determine a safe current to draw.

2- Phone is already nearing a full charge

Because of how lithium batteries work, a phone can not charge the upper 10% (Or more) at full speed, speed is reduced as the phone gets full to protect the battery from degradation

3- Battery is overheating

Your phone will charge a hot battery slower, so if your phone is sitting in sunlight or is hot in general, it will charge at reduced speeds, this as well is to protect the battery from degradation or even becoming a hazard.

4- Your power brick capabilities

Power bricks are voltage and current regulated power supplies, but they lose capacity over time and degrade, sometimes, their connection with the cable is not clean, or the plating on the pins has worn out, or the spring like mechanism of the pins no longer holds the pin tight against the pins on the USB cable, sometimes it has low capacity to begin with by design

5- Your phone has a Quick Charge capability but your wall adapter does not

Many modern phones, especially on the higher ends have a fast charging feature, where the power brick provides a higher voltage rather than a higher current, your phone will first negotiate this capability with the charger, if your charger does not support this feature, rest assured, it won’t work, and the phone will fall back to 5V charging.

If you have any questions about this matter, feel free to ask me in the comments section

Related

Prolonging the life of your phone or laptop or tablet battery

Sometimes you need to find the largest sub directory in a directory, for this, the DU command has an argument that can work for you, max-depth

du -h --max-depth=1 backup-final

The above will simply list all sub directories inside the backup-final directory alongside the size of the directory (recursive, including all files in sub directories)

One of the most annoying things that can happen to you is to disconnect your laptop from the network, then realize that there was a file moving job that was running, the command is going to get disconnected before mv gets the chance to delete the source files, the new copy is a hassle, i personally use rsync to continue such a copy with the delete source files flag

But it does not have to be this way, you can move the mv command to the background, the steps are simple

First, you need to hit CTRL+z to suspend the job, once suspended, you should see a job number in the suspend acknowledgement

Now, the next step is to disown the job, because right now, if you close your terminal window, the job will still be terminated

disown -h %1 (replace one with your own job number which may be 1)

Now to get the job running again but in the background

bg 1

That is it, you can now close (logout) your terminal window

So the summery
ctrl+z
disown -h %1
bg 1
logout

Now mind you, the output to stdout will not display (In most cases), you will need to use process status ps x to see the process.

If you want to bring back the command into the foreground, all you need to do is execute the command jobs (to find the ID), then run the command fg 1 (if it was job number one), then to hide it again, you can ctrl+z then bg 1 again (No need to disown it this time)

Sometimes, you realize you would want to use LVM in a computer but you want a tutorial to take you there fast, So i have put this post together to get you up and running in 10 minutes or less.

First, let us start with the tools, install the following packages in your debian installation, (Debian 10-Buster in this tutorial)

apt-get install lvm2 dmsetup mdadm reiserfsprogs xfsprogs

In this tutorial, I have two 8TB disks i want to combine with LVM to use as one

1- Create partitions of type LVM on the disks

• Why not use the disk without a partition ? See this post

Start by running parted on every physical disk, and creating a big partition to span the whole disk (Or if you are using empty spaces on old disks, any partition is good enough really)

In my example, where i wish to combine /dev/sdb and /dev/sdc into one logical volume (To be used as one block)

parted /dev/sdb
mklabel gpt
unit mib
mkpart primary ext4 1 100%
set 1 lvm on

Now, repeat the above, but this time for /dev/sdc

1- Prepare the physical volumes to be added to volume groups (those two partitions) (For instructions on how to add disks directly without an underlying partition which is not recommended, see here)

pvcreate /dev/sdb1 /dev/sdc1

Now, you can see what we have with the commands

pvdisplay or pvs

2- Add the PVs to a logical volume

vgcreate LVMGroup /dev/sdb1 /dev/sdc1
   Volume group "LVMGroup" successfully created

this will create a volume group (VG) called LVMGroup, you can see the VGs you have with the commands (vgdisplay, vgscan, and vgs)

vgs -o +lv_size,lv_name

3- Create a logical group on the volume group

lvcreate -l 100%FREE -n bigvol LVMGroup
  Logical volume "bigvol" created.

mkfs.ext4 /dev/LVMGroup/bigvol
or
mkfs.ext4 /dev/mapper/LVMGroup-bigvol

4- Mount, and add to fstab

To mount the volume, My mount point is at /hds/lvm

rsync is better than mv to move files because of a few reasons

First, it gives you much more control, for example the following command

rsync -a -v --ignore-existing --remove-source-files /hds/iscsi/all_new /hds/usb

Does not copy the files that are already at destination, meaning if there is a file with the same name in the same directory at the destination, it will not be overwritten, files moved will be deleted, and files that had counterparts and not moved will not be deleted

rsync -a -v --remove-source-files /hds/iscsi/all_new /hds/usb

While the command above will overwrite files, and delete whatever we have moved ! if files exist on the destination, it does not seem to be overwriting them, but it is probably somehow comparing them, then deleting the original

I had to investigate this as a move command resulting in an error did not remove the files, the error was relevant to the file name being too long

When tarring a file, even if the process (Nice) priority is low, sometimes the IO will make the computer unusable, so what you can do it ask Linux to only work on the IO intensive job when there is no other application requiring IO

ionice -c 3 -p $PID

The above class (3) means only if no other application is using this disk

The answer is, depending on your needs, but you are not here to hear that now are you, so I did a little experiment, tailored specifically for a certain need that does not apply accross the board, but combined with other experiments online, this might give you an idea

The experiment is annotating an image with image magic plugin for PHP

Both running buster (Debian/Raspbian 10), both on PHP7.3 and everything fresh installed

the PC has 8GB of DDR3 Ram, and the PI 1GB of LPDDR2-900 SDRAM

The PC has a 12 year old “Intel(R) Core(TM)2 Quad CPU Q9450 @ 2.66GHz”

The PC was around 7 fold faster than the raspberry PI 3 (the mean of a trial of 20 runs, with all the files cached in ram by the linux kernel)

The trial was done with a discrete VGA card (AMD RADEON) and with the chipset’s own graphics card, results were identical (The VGA card did not have it’s drivers installed, so we don’t know if it might have an effect or not)

I am now moving into even older PCs to compare performance, and will report the results here again to see what the limiting factors might be

Well, to make a long story short, I make large scans that don’t need to be on my system disk, I would like to have them stored on the spinning disk, So, i searched online, and found that people were suggesting that I create a symlink to the new location in place of the Scanned Documents folder, Something like

mklink /d "C:\Users\yazeed\Documents\Scanned Documents" D:\scanner

The above obviously has downsides, backup software, changed disk IDs, or other unforeseen effects, In my mind, there is no way the developers of Windows Fax And Scan have hard coded this into the application,

Another solution would have been to move the entire Documents folder (Right click it, then change it’s location, windows provides that option), But not everyone wants that, So there is a third more elegant solution (Even though this works like a charm)

The third is to look in the registry (Find) where Windows Fax And Scan stores it’s path (Look for the word scanned for example), and change that, but i Have already gone with the second, the third should be simple

The lowdown, applying grease to the fan pin works, no idea for how long (Already ordered a replacement fan from the HP website just in case), but when this fan fails, I will certainly update this post (Today is April 18, 2020).

The only reason i use my HP Envy 17-s143cl which has a slow I7-7500U (X0S43UA) is because it is silent most of the time, and quiet when the fan eventually spins up, not any more, today, the fan was very loud, and vibrates heavily, sometimes banging above the fan resolved it (Don’t try if you have a spinning disk, you will damage it, I have an SSD inside so it is okay).

So i took the laptop apart, extracted the fan, opened the fan casing, and then the plastic fan separates from the coil by simply pulling it out (With very little force, if you need any force you are doing it wrong).

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So, like you see in the photos above, I applied some automotive lithium grease to the pin, and put everything back how it was, the fan is working very smoothly, just like before, if it fails and that is a good possibility, I will update this post, but for now, it looks like a hit

Also worth mentioning is that i usually add such lubricant to PC fans, the cheap $1 fans, they usually need the lubricant after a few months, but after adding the lubricant under the back sticker on a desktop PC fan, they usually work for years more without problems, so I expect this to not give me any trouble, but in any case, I have already ordered a replacement just in case, turns out the HP store is cheaper than ebay and amazon, Just go to HP and find the part you need, mine was the one below. it cost me with shipping an all around 32 US dollars.

806747-001 In stock
FAN – for Broadwell SKU (Fanless design for Braswell SKU)
RoHS: COMPLY_2.05

Order subtotal	18.26
Shipping and Handling	11.25
Tax	2.62
Order total (USD)	32.13

In short, You can (Up to date systems) mount it in 1 go with something like

mount -o loop /path/to/my-iso-image.iso /mnt/iso

Step 1, what is the next loop number we can mount on ?

losetup -f

This will probably result in something like /dev/loop0 (Which is the next ready loop to map the ISO to

losetup /dev/loop0 /path/file.iso

Then, mount the loop device with the mount command

mount /dev/loop0 /mnt/dir

That’s it, The new solution and the old, As always, i keep things here as a not to self, because sometimes I come across older computers, and I forget how it was done since all the mounting I do now the new way