TAD (The Architect's Desktop) has one main component: TAD Designer/Lite is the one that you download and use on your computer.

It works only with your own free TAD user credentials. Note: All work is saved on your own computer/own LAN.

Psst… if you are confused about the terms TAD, TAD Designer Lite, and just TAD Designer, please read the FAQ

Hardware

You just need a computer with Windows XP or later versions. It has been tested till Windows 10 It does not consume much resources on your computer; so it should work even with a computer with 2G of RAM (Memory) Hard disk requirements are also quite low – in the order of around 20 Megabytes.

It's a 32 bit application – so would work on any kind of Windows 32 bit or 64 bit

It works quite well on Linux and also Macintosh and Chromebooks, provided you install the WINE layer into those operating-systems. You would also have to update the WINE for all the requirements of this software (Such as MSScript Control and Visual Basic for Applications)

How to setup Wine on your Linux/Mac/Chromebook

Registration and installation

This is free, and explained here