A good look back at the very early days of computing. This IBM Calculator had a massive amount of vacuum tubes that enabled it to perform its calculations easily. And it does not take up that much room either, as a bonus it would fulfill the dual role of space heater whilst remaining quiet. The picture to the right shows a close up of an IBM valve, these things were amazing to look at, the glowing element inside was a good indication that the valve was working fine, with a valve amplifier it is said that they give a nice warm sound, used in computers they do work, but take up a lot of room, that is why the ENIAC computer took up such a massive area. But due to the invention of the transistor and then the integrated circuit we now have a whole computer that can fit inside a tiny box, ie the Rasberry Pi. Computer users in the 1950`s could not have imagined something like that at all. The ENIAC computer took up an entire room and 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints.
This computer required constant maintenance due to to the number of vacuum tubes, and due to the fact that they were switching the machine off and on again, once they decided to leave the machine switched on, it was far more reliable. Nowadays we do not need to use vacuum tubes for anything except retro tube amplifiers for those who prefer the warmer sound of tubes over transistors. The photo to the right shows a computer from the 1960`s with a light pen for selecting objects on screen. The Sketchpad computer software allowed the use of a Lightpen to manipulate graphics on a computer screen. That is amazing actually, the round computer monitor is a little strange, but CRT screens for computers were only small back then, we did not have the Sony GDM-W900 24″ wide screen monitor in the 1960`s.
And the computers would not have had enough video memory for 1920×1200 resolution anyway. The first graphics card I used was a Trident 512k graphics card that could do 640×480 with 256 colors. That was nice for Windows 3.11. But these days we have integrated graphics hardware that can do better. And we do not use vacuum tubes in computers anymore, the only valves we use today are in CRT monitors, as the screen is a giant vacuum tube. As well as X-ray tubes, they are also vacuum tubes, they use a high voltage to create powerful X-Rays for diagnostic purposes. The older cathode ray tubes used in some very old model televisions could create X-rays, but most modern CRT television tubes and computer CRT monitors are impregnated with lead to shield the viewer from X-rays, rendering them safe. The only dangerous thing about the CRT tubes is when you are taking them apart and you disconnect the High Tension cable from the CRT tube, the tube circuity can store a high voltage for some time and this can be thousands of volts.
So make sure to discharge a CRT monitor or television properly before disassembling the HT circuitry.