Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site rosevax.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!stolaf!umn-cs!mmm!rosevax!hogan From: hogan@rosevax.UUCP (Andy Hogan) Newsgroups: net.micro.mac Subject: Re: Re: RAM ugrades (sockets) Message-ID: <234@rosevax.UUCP> Date: Wed, 6-Nov-85 18:17:07 EST Article-I.D.: rosevax.234 Posted: Wed Nov 6 18:17:07 1985 Date-Received: Sun, 10-Nov-85 09:37:09 EST References: <1058@decwrl.UUCP> <372@gcc-milo.ARPA> Organization: Rosemount Inc., Eden Prairie, MN Lines: 40 >In reference to the reliability of sockets: >I seem to recall the rule of thumb being: >The addition of a socketed chip, in place of a soldered chip has the >same effect upon reliability as adding another chip. I believe this comes >from an ATT manual on reliability. > >Thus, if Apple (for example) was to add socketed RAMs, it would be >equivalent, in terms of reliability, to adding 16 more chips to the >digital board. All in all, I'll take the soldered version. > > Tim Peacock Hmm. This seems like an old rule, but is probably still good if you substitute "another small- to medium-scale integrated TTL chip" for "another chip". Newer technologies and larger scales of integration have greatly decreased the reliability of chips vs. sockets. Socket manufacturers have not stood still either (they know that they get bad press on reliability) so they have increased socket reliability. Socket reliability is only one factor. When production quantities are in the region that Apple works in, the cost of the sockets (and installing them, etc.) becomes far greater than the cost savings in repair and other cost advantages of socketing. So there is enormous pressure on a large manufacturer not to use sockets. From Apple's point of view, they are a burden. From MY point of view, they were necessary when I did the Dr. Dobbs upgrade, because they allow me to replace dead chips easily and (potentially) allow me to add in 1 Meg chips when they are available (with some more hacking and new Apple ROMs which I optimistically assume I can get (1/2 :-) ). I also got very good sockets at an enormously low cost.... In any case, sockets for ICs (particularly memory and other expensive ones) are something that should be designed in until a total cost analysis pushes them out. When that happens, the manufacturer should be aware that he is trading cost against problems that are very tough to measure, such as customer satisfaction, and weigh that in the decision also. -- Andy Hogan Rosemount, Inc. Mpls MN path: ...ihnp4!stolaf!umn-cs!mmm!rosevax!hogan Working is not a synonym for Quality.