[SunRescue] 30-pin SIMMS, or Who should I believe?

[Tim Hauber]

rescue at sunhelp.org writes:
>I just went down to one of the basements here, and found 24 30-pin simms
>on
>some old 486.  Since the 486s max out at 32MB of ram, and SS2s max out at
>64
>(from simms), I thought I'd take them with me.  I've got 4x4MB 9-chips
>SIMMs, which my simm tester reports as "True Parity SIMMs".  So far,
>everything is normal and happy.  The rest of the SIMMs have 3 chips on
>them,
>and are all 1MB (oh well).  Here's the kicker, 12 of these SIMMs show up
>as
>"Logic Chip Parity", which makes sense.  The other 8 show up as "True
>Parity" SIMMs.  What gives?  Think the RAM tester is right, and they
>really
>are true parity, or is it mis-interpreting things.  One more note, the 1MB
>"True Parity" SIMMs take much much longer to test than the "Logic Chip
>Parity" SIMMs.  
>	Greg

I have seen 3 chip simms with three identical chips on them, and have
always wondered if someone made 3 bit chips (3x3=9)  But they can also be
2 *4bit and 1*1bit chips, to equal 9 bits (real parity)