This post is edited from a piece submitted for a course on the internet, probably Coursera.
My educational background was maths and science-based and at school I developed a fascination with Physical Geography and later Geology. When I graduated in 1974 computers were, generally speaking, room-sized units or at least wardrobe-sized units although some mini-computers were certainly beginning to appear by then.
Early brushes with computing
In my mid 20’s I worked as a geophysicist on marine seismic surveys using some of the earliest “portable” computers then available, the DEC PDP-8 , this was used for real-time navigational calculations based on early implementations of the satnav system (which was pretty crude at the time with accuracies from 50 to 1500 metres depending on getting the right satellites in view for tri-angulating positions).
Over the next few years, such is the pace of change, these refrigerator sized 12-bit machines with teletypes for input/output were steadily replaced by desktop sized units with more power and actual screens and keyboards. The HP 98xx series, for example, featured a nice red 256 character one-line display. Later they graduated to green screens, in-built printers and digital tape storage.
In 1976 I quit this work and went back to college at University College London. At that time they had a requirement that all post-grad students had to do an introductory 2-week course on programming in FORTRAN IV. Having taught myself a bit of BASIC on those HP machines I was up for the challenge and wrote my first program on punched cards. It printed a graph of a profile of the magnetic field over an undersea structure we surveyed in the English Channel and took a week or so to debug.
My next serious encounter with computers was in 1982 when I moved with my family to Portugal to take up geophysical consulting there and the company had bought a DEC VAX II machine to which I could connect via a terminal. At this time I also purchased my first home computer, a BBC Micro 8-bit machine, which cost over GBP 1000 and even more expensive twin 800Kb floppy disk drives – state of the art.
Subsequently I worked at an engineering laboratory and developed software on Zilog and VAX VMS machines – including connecting to a VAX VMS using Windows 2.5. Mostly we didn’t bother, it was really clunky back in 1988 and played a pretty lousy game of Othello.
Computers and Education
In 1989 I joined the local school to help them introduce computing across the board, they were already running Pascal programming. We had access to a lab of Amstrad 8256  word processors running CP/M as the operating system. The code had to be written in the Word Processor, saved to tape, then the Pascal Compiler loaded to compile the program to a CP/M executable. This tedious chore made our students very good at desk-checking code.
Later we graduated to Amstrad 1512’s  with twin floppy disk drives and running MS-DOS and GEM an early graphical user interface. I vividly remember looking at a 20 Mb (yes, not a typo) hard-drive with my colleague and wondering how on earth we would ever use all that space. Of course, all our documents then were in WordPerfect with the only diagrams made up of the character line shapes. I still have the 125-page manual we wrote (in WordPerfect) for our teacher training workshops.
It was with these machines that we first connected to the outside world using the CIS (Compuserve Information Service). This was the company that brought you the RLE  and GIF image standards, for better or for worse.
Compuserve was a “walled garden” with email service and access to many different support forums for its own services and services offered by other companies. If memory serves, we could also access Gopher (text-based tool) that permitted searching internet connected servers and examine their public contents. This was how much of my early educational research was carried out.
A Gopher screen looks something like this 
To give a flavour of these times, it was already being recognised that the internet was a big treasure trove (albeit mainly text-based):
“But now that the Net has become a rich repository of information, people are looking at ways to make it far easier to find all that data. Gophers and Wide-Area Information Servers (WAISs) are two programs that could ultimately make the Internet as easy to navigate as commercial networks like CompuServe or Prodigy.” 
This was an exciting and frustrating time for educators. As I wrote myself, looking back 
“I knew technology could change the classroom but I still didn’t know how to achieve it in a conventional school where technology was just another subject and maybe one or two teachers were savvy enough to incorporate some of it into their teaching.”
By the time I left Portugal for Singapore in 1998, the web had become commonplace – a few companies had even started to put their URL’s into their advertisements. While Tim Berner’s Lee started the web back in 1989 , it was a little while before it began to take off.
I started my first website at around this time (http://www.ib-computing.com) and it was a crude but effective resource which only grew as other teachers and students began to visit it. It became the #1 site on Google (or possibly Alta Vista) for the International Baccalaureate Computer Science course and eventually led to a text book. I still sometimes get requests for the site from teachers which I retain in zipped form. It had some interactivity based around early offerings of Macromedia, later swallowed by Adobe.
By 2006 I was already teaching other teachers using Moodle – a Learning Management System then just beginning to take off. In that year I also took up a post in Beijing, China where some modest success was achieved with some teachers making extensive use of Moodle to supplement and enhance their teaching.
The key barriers then, and probably now, were the complete failure of Senior Management to see the possibilities of educational computing.
In 2010 I was offered a position at The Southport School in Queensland to set up and introduce Moodle there as a way to improve academic attainment. This was very successful and you can read more here: https://elearningindustry.com/how-an-lms-and-byod-changed-a-school.
Today we see the possibilities of education in a tech-saturated environment, where all learners have 24/7 access both to resources and to teachers (not only their own but via MOOC’s to some of the best teachers on the planet).
Finally, we can change teaching to become truly learner-centred and largely autonomous but, especially for young people, teachers as mentors to guide them through the perils it also brings. Especially relevant is the ability (lacking in many adults it seems) to evaluate sources of internet information for credibility, authority and reliability.
I’ve grown up first with computing machines, with the internet, finally with mobile and social computing. To see what technology has achieved over 50 years of my professional life is truly staggering.
As an eternal optimist, the future looks bright to me.
Thanks for reading.