Real World Wi-Fi Speeds
| IEEE standard | Wi-Fi Alliance Standard | Theoretical Speed | Real-world Speed |
| 802.11ax | Wi-Fi 6 | 10Gps | 700Mbps |
| 802.11ac | Wi-Fi 5 | 1.3Gps | 200Mbps |
| 802.11n | Wi-Fi 4 | 600Mbps | 150Mbps |
Wireless Broadband Alliance (WBA) real world trials carried out in the “hostile” environment of the Mettis Aerospace facility in the UK West Midlands.
https://www.theregister.co.uk/2019/12/05/wifi6_700mbps_speeds/
Use Catfish to find files and file content quickly – note content search only works for text type files. Use Recoll for other file types.
Install using Synaptic Package Manager or from Terminal as follows:
sudo apt install catfish
Run it by selecting it from from Utilities or use the Search function and enter Catfish to locate.
Once running you should see screen below.
To search for content first click the settings cog and check “Search File Contents”. This will then force Catfish to search for the string in the files within the top directory you have selected to the left of the search box. In this example we are searching for the content string “tooltip” within files in the the top folder “scss”. The number of hits (3) and files are displayed that contain “tooltip” in the main window. To open a file double-click it.
To search for file names only uncheck “Search File Contents”
Follow steps below to enable F8 safe mode boot (applies to Windows 10 and 8.1):
Type the following command to enable F8 Safe Mode boot key:
bcdedit /set {default} bootmenupolicy legacy
Type Exit and press Enter to quit the Command Prompt. Remove your usb flash drive or DVD and turn your computer off. When you start your PC, you can now press F8 to get the Advanced Boot Options menu
If you don’t have a spare Mac or your Mac is too old to download macOS from the Apple App Store then use the method below.
Create account on hackintosh.download
The download required macOS from https://www.hackintosh.download/category/3-macos/
Insert a usb (16GB+ recommended) into Linux PC usb port and run Terminal
Use fdisk to determine your usb dev name letter, e.g. /dev/sdc. It is very important to note the correct device letter or you may overwrite your own system or data drive!
sudo fdisk -l
Use dm2img to copy macOS (OS X El Capitan in this example) to your usb device (sdc in this example). This completely overwrites whatever is on the usb drive already!
sudo apt install dmg2img # install dmg2img if not installed sudo dmg2img -v -i ./EL_Capitan.dmg -o /dev/sdc Output from dmg2img... dmg2img v1.6.7 (c) vu1tur (to@vu1tur.eu.org) ./EL_Capitan.dmg --> /dev/sdc reading property list, 361779 bytes from address 6237611619 ... partition 0: begin=192, size=430, decoded=284 partition 1: begin=908, size=430, decoded=284 partition 2: begin=1611, size=356137, decoded=239844 decompressing: opening partition 0 ... [2] 100.00% ok opening partition 1 ... [2] 100.00% ok opening partition 2 ... [5991] 100.00% ok
When complete eject the usb to flush IO buffers (important!) by clicking on the usb icon on the desktop and click remove | eject.
Insert usb in your Mac and power-up holding down the Alt | Option key until the Install usb icon is displayed in the middle of the screen.
Select the install usb to install macOS
Once in Recovery mode select Disk Utility to erase disk (if new drive or clean install)
Exit Disk Utility
Select mac OS to install from main menu and install to your main HDD or SSD
Note: the download source above is not Apple approved. To be safe, once your Mac is up and running, download the mac OS again from the Apple Store and re-create the install usb and carry out a clean install.
Display details about firmware, cache, memory
$ sudo lshw -C memory
*-firmware
description: BIOS
vendor: FUJITSU // Phoenix Technologies Ltd.
physical id: 0
version: 6.00 R1.06.3012.A1
date: 04/21/2011
size: 110KiB
capacity: 4032KiB
capabilities: pci pnp upgrade shadowing escd cdboot bootselect int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb ls120boot zipboot biosbootspecification
*-cache:0
description: L1 cache
physical id: 5
slot: L1 Cache
size: 64KiB
capacity: 64KiB
capabilities: burst synchronous internal write-through data
configuration: level=1
...
*-memory
description: System Memory
physical id: 2a
slot: System board or motherboard
size: 16GiB
*-bank:0
description: DIMM DDR3 Synchronous 1067 MHz (0.9 ns)
product: 99U5471-021.A00LF
vendor: Toshiba
physical id: 0
serial: DE131F7C
slot: Slot-1
size: 4GiB
width: 64 bits
clock: 1067MHz (0.9ns)
...
Test and Benchmark 3D Graphics
sudo apt install glmark2 glmark2
Some less well known Windows 7, 8.1, 10 Terminal (cmd) commands
| Command | Description |
| powercfg /batteryreport | Detailed battery diagnostics > html |
| netsh wlan show wlanreport | WLAN data last 3 days > html |
| Alt+Enter | Full screen mode |
| F7 | List previous commands |
| doskey /history > c:\cmd.txt | Save command history to \cmd.txt to view last saved history session |
| msinfo32 | System Summary > BIOS version amongst others |
| findstr /s dinosaur *.txt | Search inside your files with findstr add /s to search subfolders |
| sfc /scannow |
Fixes corrupted system files by replacing them with fresh ones from the local Windows recovery image |
| dism /online/cleanup-image /checkhealth |
Check the health of the recovery image. If you see a message saying corruption has occurred run command below |
| dism /online /cleanup-image /restorehealth |
Fix recovery image. Only run if you have Checkhealth errors |
| powershell |
Switch to Powershell in same window |
| start powershell | Start Powershell in a new window |
| Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”} | Powershell command to reinstall Microsoft Store core Windows 10 apps |
| cipher /e c:\Vault |
Replace “c:Vault” with the Folder or file to encrypt. To unencrypt right-click folder or file, select Properties; Advanced and untick “Encrypt contents to secure data” option. |
| shutdown /r /o |
Boot to Windows 10 advanced options |
| netsh wlan show profile netsh wlan show profile WiFi-name key=clear |
Recover forgotten WiFi password. Replace WiFi-name with the one shown in list of network names (1st command). Scroll through results to see password shown against WiFi-name |
| robocopy c:\users\username\Documents d:\backup\Documents /mir /copyall /dcopy:T /r:0 /w:0 /log:c:\users\username\log.txt /tee |
Copy folders fast – mirror the source to the destination copying all files and folders, including empty ones + all file attributes including NTFS permissions and copy timestamps and retry 0 times and wait 0 secs between retries and logfile and log output to console and logfile |
This method depends on the iso file being designed as bootable, e.g Kaspersky Rescue Disk or Bitdefender Rescue CD, etc.
Plug in the USB flash drive and list its device name using fdisk
sudo fdisk -l . . . Disk /dev/sdc: 3.8 GiB, 4009754624 bytes, 7831552 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x052e500d Device Boot Start End Sectors Size Id Type /dev/sdc1 * 2048 7831551 7829504 3.8G c W95 FAT32 (LBA)
Unmount the device partition, e.g. sdc1.
umount /dev/sdc1
Copy the iso. file to the device (sdc) not the partition (sdc1). Note the larger block size (4M, default 512bytes) to speed up the transfer. The usb light will flash during copying. Note this can take a long time depending on iso file size. Be patient. When finished dd displays a summary report of bytes copied.
sudo dd if=filename.iso of=/dev/sdc bs=4M
Finally flush the io buffers and eject
sync sudo eject /dev/sdc
A slip-up of adding an extra ” to a string definition highlights an anomaly in Sass which causes it to flag every line of scss code (including comments) with double quotes as an error including the real error lost in the jungle of errors. See example below with ” added to the end of $fontfamily (not easy to spot) and an excerpt of the Sass compiler error message pointing to valid line of code amongst many more misleading messages.
$fontfamily: "Comic Sans MS",Arial,Helvetica,sans-serif!important"←;
Error in plugin "sass"
Message:
src/scss/style.scss
Error: Invalid CSS after '...nd-image: url("': expected expression (e.g. 1px, bold), was "../images/Computer_"
on line 430 of src/scss/style.scss
>> // background-image: url("../images/Computer_Doctor_1800x1149.png");
All this confusion leaves you scratching your head trying to figure out what’s suddenly gone wrong leading you down false trails, e.g. thinking Sass has been updated to a buggy version or should I replace all double with single quotes or whatever.
Once you’ve tracked down the real error line and removed that extra ” all the other error messages miraculously disappear – phew!
I hope this revelation saves you many hours of lost productivity.
Gibson Research Corp.’s Shields Up port-scanning service at https://www.grc.com/shieldsup will test your router for hundreds of common vulnerabilities, most of which can be mitigated by the router’s administrator.
IPv4
OpenDNS (208.67.220.220, 208.67.222.222) Google Public DNS (8.8.8.8, 8.8.4.4) Cloudflare (1.1.1.1, 1.0.0.1)).
IPv6
OpenDNS 2620:0:ccc::2 and 2620:0:ccd::2 Google 2001:4860:4860::8888 and 2001:4860:4860::8844 Cloudflare 2606:4700:4700::1111 and 2606:4700:4700::1001.
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