24 Jan
2013
24 Jan
'13
12:59 p.m.
[Possibly apocyphal stories]
"RS "32K" RAM were 64K where only one
half tested bad" (YES, they
were 64K, but who had sufficient quantity to MARKET half-defects?)
That one may be correct. I seem to remember that the 32K DRAMs were
aviaalble in 2 versions correspodnig nto low-half (or a 64K chip) good
and high-half good. You had to hold the A7 input in the correct state
when loading the column address.
I think some Sinclair Spectrum boards (although not, IIRC, the CoCo) had
a jumper which tied the aprorpriate input of th address multiplexer high
or low. You had to fit 8 32K RAM chips of the same type and set the link
acordingly.
-tony