Dear Baba,

To advance our technical eduction of the computer sciences a little.  Thermionc valves preceeded transistors it seems. 

I remember father thumping the top of the wireless set to reseat such valves whenever it played up. 

I googled the following: from Engineering .com 

The invention of the transistor in 1947 opened the door to the information age as we know it. But computers existed before transistors did, albeit in a rather rudimentary form. ... Rather than being built out of transistors, these behemoth computers were made up of something called thermionic valves, aka vacuum tubes.  

I have a one byte memory board measuring 10 x 5 x 1 inches with settings for 8 thermionic tubes (valves) as a paper weight. This I found in a skip.  It was from an old IBM machine at the RAPC Computer Centre Worthy Down where I worked quality assuring applications to pay and administer the British Army.  Lap tops today have a terabytes of memory these days and don't need to be housed a large cooled room. 

The POET OI is 1 x 1 mm I think.  What degree of revolutionary progress is  that 1 x 1 mm of magic is going to produce  I wonder Aye?

Just glad that we were both wise to invest in such a marvellous technology, more by luck than judgement in my case.

Your friend as ever,

sula