3 ms·

I've always wondered if the ROMs on my VAXstation 4000/90a are ferroelectric. The DEC manuals refer to it as flash ROM, but I've also heard / read it referred t

I've always wondered if the ROMs on my VAXstation 4000/90a are ferroelectric. The DEC manuals refer to it as flash ROM, but I've also heard / read it referred to as FRAM, although I couldn't say I remember where or when. But 512KB of FRAM at $3 per megabit would make that pricier than the machine! So I wonder what it has in it instead. Interesting! Thanks :)

kens 2y ago
It wouldn't make sense to use FRAM for ROM, since the big feature of FRAM is fast write speed. I found one DEC document that says the Flash ROM on one product is the Intel 28F008SA, an 8Mb flash chip. So I expect the VAXstation uses boring flash too, rather than costly FRAM. Link: https://bitsavers.org/pdf/dec/semiconductor/arm/EC-QU5KA-TE_SA110_Evaluation_Board_Reference_Manual_199603.pdf https://bitsavers.org/pdf/dec/semiconductor/arm/EC-QU5KA-TE_...
- sroussey 2y ago
  What would be good for DRAM read speeds, and not care too much write speeds? I’m thinking of keeping an LLM’s weights in a storage RAM, where it would be updated only every few months.
  - namibj 2y ago
    DRAM or SLC NAND. Be careful with read-induced disturbance on the latter, though.