1968 white ceramic PGA

[FunctionalLimits]

Can anybody help me ID this chip? I've seen a very similar AMI package, but I can't figure this one out. The photo quality is not great, but apparently the manufacturer's logo is "NS," which presumably is Nat Semi, and I assume the last 4 numbers are the date code.

[johnorun]

The date code is on the first line..."429" = 7429.

Burroughs, the old mainframe company, also used these chips in their 1970's machines and they had the "B" logo instead.
Your pic is a little too fuzzy for me to make out the NS logo.

[FunctionalLimits]

Thanks! If you don't mind my asking, how did you know that the first line is the date code? Do you know of a link I can refer to in order to learn the various marking conventions? I'm fairly new at this, and I still often have trouble deciphering the meaning of these manufacturers' codes.
I can't read the logo in this photo either, but it's the only pic I have at this point. It's from someone who has offered to sell it to me.

Edit: In partial response to my own question, there is some info on more recent NS marking conventions here:
http://focus.ti.com/quality/docs/gencontent.tsp?templateId=5909&navigationId=12626&contentId=153966

[Guest]

Many date codes from the 60's and earlier 1970's leave off the decade number so 26th week of 1974 would look like "426" instead of "7426".
We can assume that 3 digit date codes on CPU chips are from the 1970's since the first CPU was produced in 1971 - the Intel 4004.
I don't recall seeing any 3 digit date codes after the mid 1970's.
Hope this helps.

[johnorun]

My post above...

[FunctionalLimits]

Much appreciated.