Quantity[] requires internet access. Is there any workarounds?

Question

Quantity and QuantityArray are great tools for working with types arrays (in terms of physical units), perform conversions and etc.

I have discovered recently, if there is no internet access (horrible!)

Quantity[1, "Millimeter"]

it returns

Quantity::conopen: Using Quantity requires internet connectivity. Please check your network connection. You may need to configure your firewall program or set a proxy in the Internet Connectivity tab of the Preferences dialog.

Is there any way of working with them offline. Wolfram Language should be some built-in knowledge about SI or Gaussian units. Should I reinvent the wheel and make my own units system to overcome this issue?

I believe it might also slow down the kernel, if there are many of them. Does Wolfram Kernel always go to the internet to convert every single one?

Answer 1

I have found by accident, that WL only requires internet if the form of the units is not conventional. In my example I should have used a plural form:

Quantity[1, "Millimeters"]

This works without the cache and the internet.

Answer 2

If you have Internet access prior to you work, you may try to force MMA to cache the function Quantity:

• First turn on the Internet
• Then evaluate e.g.: Quantity[1,"Meter"]
• Then turn off the Internet
• Now you can use Quantity without Internet access

This will work even if you terminate your language session with Quit[] and start a new session. (Note, this is valid for MMA version 14.1)