so I brought the 3000 home, snapped a shot of the ram and found it's not Sram and it's not Dram
it's called static column ram - which is as close to Sram as you can get (but not Sram, yet we called it that).
Its not close to sram at all other than similarly sounding name, as I wrote in previous post it is an improved variant of page mode DRAM:
>and here a definition of "static column mode" in case you would somehow think this means SRAM: https://www.jedec.org/standard...
even wiki has a section on it https://en.wikipedia.org/wiki/...
In fact if you search for 9A9Z you get all sorts of answers of what it is.
a big hints are
-a whole timing diagrams section on refresh
-multiplexed address bus
-fact 4Mbit sram chips didnt exist until 1993, and when they first showed up they were >$140 a pop!!!
-and fifth word of the datasheet reading 'dynamic' :-)
This ram allows the same search and grab as Sram,
Now we are moving 2 posts back. You are confusing two separate things, type of ram and ability to recover data after reset. Those two are independent.
Both types of ram will keep its data mostly intact over a reset, and somewhat intact after total power loss depending on process size, temperature, time etc.
Difference between SRAM and DRAM is in physical construction. One uses multiple(4-8) transistor latch arrangement - you put logic level in and it stays there until powered down. The other uses _one_ transistor and capacitor and needs frequent refresh (recharging that capacitor).
More transistors to build sram means more expensive, around x10 was the minimum. This is why in the nineties a 256KB sram cache for a PC motherboard cost around the same as 4MB simm. This price difference (and use of slow processors) was the reason not a single Amiga featured sram.