Old 30 pin and 72 pin memory

[Glory_Cloud]

Here are some oldies!!

[UMMR]

Nice vintage RAM modules. The first from the top is 1 MB, 85 ns, parity, for the IBM PS/2 Model 50Z. Each chip is in fact a sort of multichip, or hybrid module, with two memory chips inside. The same package can hold a maximum of 4 memory chips, as in the 4 MB memory cards for the AS/400. The second is a 256 KB SIMM for the IBM PS/2 Model 30. I really love these unusual IBM SIMMs.
Paolo

[Tetrium]

Never seen the top 2 before, though I have 2 of those IBM aluminium box memory modules with 6 of those little boxes in a row.

And thanks for the info UMMR, I never knew what the deal was with those aluminium boxes

Is this a picture thread btw? If so, the 72p memory modules are missing, so here to fill it in


These are double sided 72p 64MB 60ns FPM modules. Some are tin and some are gold plated. I know they are supposed to only work in a few HP servers but I tried them in a Socket 7 and a Socket 3 board and they posted and counted fine. But they did become unstable after I started loading the OS though. Switched back to the old memory modules and instability was gone.

[max3]

[Neon]

SIMMs are before my time of experience. I think these are 1 MB.

Each module has 2 chips marked HY514400J-70, and a 3rd chip HY531000J-70. I presume the 3rd chip is for parity. There is a datasheet for HY514400J-70, which indicates it is a Hyundai 1Mx4-bit chip. So:

1M x 4-bit = 4 Mbits = 512 KBytes per chip

2 chips = 1 MByte per module

70 ns = 14 MHz