From: "g.g.coombes" Newsgroups: alt.folklore.computers Subject: Memory Lines: 5 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Message-ID: Date: Wed, 14 Mar 2001 22:46:54 -0000 NNTP-Posting-Host: 62.255.116.187 X-Complaints-To: abuse@ntlworld.com X-Trace: news2-win.server.ntlworld.com 984609874 62.255.116.187 (Wed, 14 Mar 2001 22:44:34 GMT) NNTP-Posting-Date: Wed, 14 Mar 2001 22:44:34 GMT Organization: ntlworld News Service Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!feed2.news.luth.se!luth.se!news.tele.dk!212.74.64.35!colt.net!newspeer.clara.net!news.clara.net!news5-gui.server.ntli.net!ntli.net!news2-win.server.ntlworld.com.POSTED!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:76832 I have a pc66 and i thinks the memory chips are sdram dim Can anyone tell me of this is right. i have no idea about computers,so any advice would be nice. ###### From: Erno Palonheimo Newsgroups: alt.folklore.computers Subject: Re: Memory Date: 15 Mar 2001 01:05:17 +0200 Organization: Helsinki University of Technology, Finland Lines: 11 Message-ID: References: NNTP-Posting-Host: theremin.hut.fi X-Trace: nntp.hut.fi 984611117 28284 130.233.200.16 (14 Mar 2001 23:05:17 GMT) X-Complaints-To: usenet@nntp.hut.fi NNTP-Posting-Date: 14 Mar 2001 23:05:17 GMT X-Newsreader: Gnus v5.3/Emacs 19.33 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news-fra1.dfn.de!news-fra.pop.de!newsfeed.wirehub.nl!news.tele.dk!129.240.148.23!uio.no!newsfeed1.funet.fi!newsfeeds.funet.fi!news.cs.hut.fi!nntp.hut.fi!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:76865 "g.g.coombes" writes: > I have a pc66 and i thinks the memory chips are sdram dim > Can anyone tell me of this is right. i have no idea about computers,so any > advice would be nice. No. They're ferrite core memory, your local computer dealer quite likely has some of that in stock. -- Erno Palonheimo ; esp@iki.fi ; http://iki.fi/esp/ ; +358505604765 ###### From: "Jack Peacock" Newsgroups: alt.folklore.computers References: Subject: Re: Memory Lines: 61 MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.3018.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.3018.1300 Message-ID: Date: Wed, 14 Mar 2001 17:31:13 -0800 NNTP-Posting-Host: 208.57.2.36 X-Complaints-To: abuse@primary.net X-Trace: news1.primary.net 984619988 208.57.2.36 (Wed, 14 Mar 2001 19:33:08 CST) NNTP-Posting-Date: Wed, 14 Mar 2001 19:33:08 CST Organization: Primary Network http://www.primary.net Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!enews.sgi.com!newsxfer.eecs.umich.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.skycache.com!Cidera!rupert.mfn.org!stl-feed.news.verio.net!news1.primary.net!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:76871 "Erno Palonheimo" wrote in message news:uthr900gdea.fsf@theremin.hut.fi... > "g.g.coombes" writes: > > > I have a pc66 and i thinks the memory chips are sdram dim > > Can anyone tell me of this is right. i have no idea about computers,so any > > advice would be nice. > > No. They're ferrite core memory, your local computer dealer quite > likely has some of that in stock. > That's right, the "PC66" stands for Perkovskite Core 66 (66 cores per nanometer) as opposed to the newer 100 cores/nm and 133 cores/nm type memories. These are the newer, more advanced solid state core memories where the toroids were replaced by Perkovskite crystals. Be sure to ask for the CAS/2, or Core Addressing Strobe 2 microsecond, versions. This is the critical timing for the write pulse that recovers the data stored in the magnetic field. It's not so well known that a write pulse slower or faster than 2 usec will cause flux stress in the core and eventually cause it to crack, so be sure to specify the 2 usec CAS strobe time. You need not worry about the RAS, Rewrite Addresing Strobe, as this will automatically occur synchronously to the initial write (hence the tern Synchronous memory). However, as always be sure to install the Faraday cage around your memory once it is in place on the motherboard, otherwise you will be susceptible to electro-magnetic pulse bit errors. Naturally you will want the DIMM (dual inline magnetic modulator) wired versions. Unlike the SIMM (single inline magnetic modulator) of older designs the DIMM has two wires, one for the write pulse, and a sense line to return the magnetic field polarity. The older SIMM memories only had one wire running through the ferrite/perkovskite cores and had to multiplex write pulse/sense line functions. DIMMs double the access speed by eliminating the MUX timing cycle so the memory can be written/read/rewritten at the same time. Whatever you do, do not try to use RAMBUS (Radio Active Magnetic Bubble Un Shielded) memory. Only properly certified technicians can install this type of core memory. When used with CPUs clocked over 1GHZ the radiation emitted from improperly installed RAMBUS can exceed 500 millicuries/hour. Any wonder there are so many lawsuits involving RAMBUS? Any PC store should be able to supply all these types of core memory. But make sure the tech gives you the right sized Faraday cage to go with the parts (SIMM cages are extruded brass, DIMM cages are braided copper, and RAMBUS cages are solid lead). The manufacturer supplies this free but many unscrupulous dealers will pretend not to know what the cage is, so you will have to return for a service call months later, after the warranty expires. Good thing you asked in the folklore group where oldtimers had to learn all the intricacies of magnetic memories. A lot of people will try to tell you that memory is made out of silicon, which of course is absurd. Ever try to find the north (1) or south (0) bit on a grain of sand? (Note I used the northern hemisphere equivalents, as we all know south of the equator all bit polarities flip.) Jack Peacock "Why is my hair falling out?" last words from a do-it-yourself RAMBUS user ###### Path: chonsp.franklin.ch!not-for-mail From: Neil Franklin Newsgroups: alt.folklore.computers Subject: Re: Memory Date: 16 Mar 2001 21:55:48 +0100 Organization: My own Private Self Lines: 22 Message-ID: <6u3dcda0x7.fsf@chonsp.franklin.ch> References: NNTP-Posting-Host: chonsp.franklin.ch X-Trace: chonsp.franklin.ch 984776148 608 10.0.3.2 (16 Mar 2001 20:55:48 GMT) X-Complaints-To: news@chonsp.franklin.ch NNTP-Posting-Date: 16 Mar 2001 20:55:48 GMT X-Newsreader: Gnus v5.7/Emacs 20.4 Xref: chonsp.franklin.ch alt.folklore.computers:76900 "Jack Peacock" writes: > That's right, the "PC66" stands for Perkovskite Core 66 (66 cores per > nanometer) as opposed to the newer 100 cores/nm and 133 cores/nm type > for the CAS/2, or Core Addressing Strobe 2 microsecond, versions. This > You need not worry about the RAS, Rewrite Addresing Strobe, as this will > > Naturally you will want the DIMM (dual inline magnetic modulator) wired > > Whatever you do, do not try to use RAMBUS (Radio Active Magnetic Bubble > Un Shielded) memory. Only properly certified technicians can install ROTFLBITC! That one is a keeper. -- Neil Franklin, neil@franklin.ch.remove http://neil.franklin.ch/ Hacker, Unix Guru, El Eng HTL/FH/BSc, Sysadmin, Roleplayer, LARPer