[NikolaNovak]

I used to be a professional computer geek on weekdays and professional photographer on weekends; and 20 years on, it still blows my mind the similarities between the materials and manufacturing of the CPU doing heavy work in my laptop and the sensor gathering pixels in my camera :O

[genericone]

Transistors!

E.g. EPROM (memory type chip) is typically deleted by shining a uv light on the actual silicon die, through a uv transparent quartz window in the final packaged chip.

edit: fixed EEPROM -> EPROM

[analognoise]

That's not an EEPROM. That's an EPROM. The first E in EEPROM is ELECTRONIC - i.e. you use a voltage (or a control word) to indicate that you would like to erase the device.

Also, EPROMs are extremely vintage. They were replaced by EEPROMs - the first of which came out in 1977. That's an... extremely vintage example.

[dragontamer]

> Also, EPROMs are extremely vintage. They were replaced by EEPROMs - the first of which came out in 1977. That's an... extremely vintage example.

IIRC, EPROMs were still cheaper than EEPROMs for many years. EPROMs probably were sold in commercial quantities well into the 80s, and maybe used in the 90s.

EPROMs were erased by just throwing them into a UV-bin and blasting them with UV light. In contrast, EEPROMs needed transistors inside to handle the erasing cycle.

Finally, EPROM's last stand was as a low-cost one-time-programmable ROM (aka: PROM). All you had to do was make the same chip except without the expensive "window" (that'd normally receive UV-light for erasure).

[lb1lf]

Studying EE in the late nineties, I can remember coming across EPROM microcontrollers a few times, but definitely not in new projects.

IIRC, students recently graduated when I was doing my freshman year had used them for projects in their freshman year, but not since - so they were probably commonplace until 1990 or so. At least in Trondheim, Norway.

[jjoonathan]

I just flashed (literally, shined UV light through the window) and reprogrammed a few EPROMs on a pair of HP 83623a signal generators yesterday to facilitate moving a module from one, where we didn't need it, to another, where we did.

Industrial equipment moves at a different pace, and in these days of 10x price jumps and "52 week" lead times, sometimes dusty relics from the 80s wind up being relevant in 2022!

[babagabooj]

True. I was there. So were you, I assume. The previous poster was most likely speculating.

[dragontamer]

Nah, I'm once removed.

I had professors who were active during the time and gave me the rundown. I have touched EPROMs and all that good stuff, still part of the labs at my college and my professor liked talking about "the good ol days". But I've never in fact used them in any practical manner.

[analognoise]

No, I know they cost less for a while, but the 90's were 30 years ago.

That's vintage, isn't it? In the 90's, stuff from the 60's was 'vintage'. By 2022... the 90's are vintage?

[AnimalMuppet]

We look back on the 60s with nostalgia. The 90s? Not so much. I think that colors our definition of what is "vintage".

[genericone]

Fixed

And thanks for the info, I don't have direct experience dealing with EPROM and I had conflated EEPROM and EPROM together in my mind, but a quick google search quickly reveals my inadequate knowledge, which has now been updated, even if only good enough for trivia.

[mywittyname]

Hence, why we "flash" certain components.

[moltke]

I read somewhere that some people used EPROMs and decaped Ram chips as digitizers for early computers.

[01100011]

https://hackaday.com/2014/04/05/taking-pictures-with-a-dram-...

Yeah I remember a friend of mine back around '90 wanted to try it out. I can't remember if it was using DRAM or EPROM memory though. I want to say it was called 'ramra' or 'ramera'.