10 May
2012
10 May
'12
2:19 p.m.
There was some debate at VCF East whether this
"IBM 256KB Memory
Card" P/N 6407740 is a bubble memory card (pic below). The card was
on display with my IBM PC 5150 exhibit. I originally pulled it from
an IBM 5155 portable.
http://www.vintagecomputer.net/ibm/5155/ibm_256KB_memory_card_6407740.
jpg
I am certain those are 64 KB CMOS DRAM chips, not bubble memory. I've seen
them on 30-pin SIMMs too.
Camiel.