Now I am not 100% sure what to ask here as I still don't haven't joined all the dots. So, how well do you understand the underlying connection between hardware and software.

For example, we use the word abstraction at this topical level, we can code some assembly language(which I know very little of), assembly it, and hey presto the 'mouse cursor' moves over the screen, or we could colour some pixels in.

But what is actually going on at the very base level. If you download mikeOS - a small OS written in assembly - well it is pretty cool, it displays a console type menu and also has a basic compiler. But it's really fundamental compared to modern OS's and I am trying to understand it, but that will be hard until I learn assembly language.

So we type in human readable language into the editor, compile/link it, and it magically switches on and off electrical transistors.

So say you were given a PC with a blank HD and you were asked to just create a mouse/icon tht you could move around the screen how would set about doing this. I understand that 80/90's 8-bit assembly programmers will have a good idea about this.

Where is the root point where we can start everything, does the hardware like mouse input have it's own firmware/software pre-built in that allow use it communicate with it?

If an assembler is the most fundamental piece of software how would you load it onto the HD/memory in the first place?

I think my real problem is that I just don't understand the complexity/structure and in built software of the hardware itself so I still can't make that connection between the 'software/text' that we see on the screen and the electronics themselves.

One of things that you have to remember is that your concept of "mouse" is really just an area in video memory being written to in a certain way which would produce a recognizable image as "cursor". this is accomplished by operations at the cpu level that produce a value that the video output understands to be a certain "color". The reason why I use quotations is because these concepts dont exist to the computer, but are manufactured so that you as the user can intetact with the system to produce meaningful results. Assembly is just a human readable form of binary data, and what a higher end compiler does is translate its easier to read langauge into binary instructions for the cpu to assign memeory locations a value that can later be used to do something.

And I know this, to a degree, and this is wha,t I am asking although couldn't put it into absolute words, I think I should really be told, 'go and do a degree in Electrical Engineering' or 'go and work for Intel' or 'buy an old mainframe/punch card computer and start from basic principles'.

My understanding is that sort of thing is covered pretty well under a CS degree. I would think that would be the place to start looking if you're aim is to make a career in hardware.

I've forgotten a lot of my micro-controller education which I took back in the mid 90's (I just don't use it in my day to day work). About 10 years ago I came across the xGameStation.com website and bought one of their educational packages they offered at the time. Though I never started working with I found that the books, CDs, and equipment that were included covered everything that my college course had. I think the main difference was that they provided a PCB to work with while my college course had us wire wrapping IC sockets.

There's an awesome book called 'CODE' which is a great read. It doesn't get you all the way there (and gets a bit lighter / fluffy near the end through necessity), but is enough in my view to feel comfortable about what is going on at the very lowest level - atleast in a simplified / early computer way. Modern computers and various layers from OS upwards are just extensions / additions. you won't regret reading it.

http://www.amazon.co.uk/Code-Language-Computer-Hardware-Software/dp/0735611319/ref=sr_1_1?ie=UTF8&qid=1405430673&sr=8-1&keywords=CODE

If you are interested to learn low level assembly language on the PC, the "easiest" way is probably to install DOS Box, which is a nice piece of software that you can use to run really ancient software on modern computers. Mac version is called Boxer. The thing with DOS Box is that it emulates the environment of old, old "IBM compatible" computers as it were back then, with BIOS, VESA graphics, sound blaster, and all. Another nice thing with good old dos, is that it ran in something called 'real mode', which basically is non-protected, segmented memory model. Translated to more understandable phrases, that means you can take over the whole computer, set any graphics mode you want, play audio at the "lowest" level, or take over all interrupts without the operating system protesting at all. Switching to a VESA graphics mode is fairly easy. It is just calling one interrupt that is set up by the BIOS. Then you can write directly into video memory to create all the graphics you want, all without the hassle to write a basic operating system yourself, with complex pre-loaders and loaders and kernel and hard drive interfacing and all those really hard, complex things. I think what I used back in the day, was masm.