Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Keithr0 Newsgroups: aus.computers Subject: Re: Glass sided computer cases Date: Tue, 7 Jan 2025 11:58:08 +1000 Lines: 43 Message-ID: References: <677c48c3@news.ausics.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net i0WNrWvRnk4EmJWtHYvjKAraviDm0PhUt5ez2jfrcOIQjiHCEl Cancel-Lock: sha1:I5xD2Quyz101OL3dkH58hDvmw8Q= sha256:pQCF16zOFk9UauMW7PAZGuCVavwDKZSTAzn4ZngzE8M= User-Agent: Mozilla Thunderbird Content-Language: en-US In-Reply-To: <677c48c3@news.ausics.net> Xref: csiph.com aus.computers:71715 On 7/01/2025 7:18 am, Computer Nerd Kev wrote: > Mighty Mouse <"squeak!"@thecheesefactory.com> wrote: >> >> Many cases now have glass sides. but what about radiation from the >> components inside? cases were all metal to shield radiation. > > Well the fronts always tended to be plastic, so a clear plastic (or > I guess top-end models _might_ use glass) side isn't that much > different for shielding. > > Laptops are already unshielded though (mine drowns out weak FM > radio stations when it's running), and EM radiation from poorly > shielded USB cables (and before that serial cables) are well > known in the form of "mouse noise" picked up by PC speaker cables > running nearby. > > The computer world is already a mess of EM noise, so I don't think > clear case sides change much. Users could always fit some wire mesh > inside the case window if concerned about it anyway. > > I do quite like this approach to a clear PC case: > https://hackaday.com/2019/06/10/somethings-fishy-about-this-computer/ > Back in 1980, we were replacing an IBM370 with a Fujitsu M180 at National Library. During the changeover both system were run in parallel to the point where every desk that had an IBM terminal, had a new Fujitsu one as well. A problem arose when the Fujitsu terminal was switched on, the IBM terminal stopped working. This seemed reasonable to us 🙂 but the customer demanded a fix. After a bunch of other people had been unable to fix the problem, I was asked to take a look. The terminals were completely dumb, all the smarts were in the controller. Each controller ran, I think, 16 terminals with a coax cable between. One thing that I noticed was that the signal return was not ground, the two were connected by a capacitor at the controller end. I tried fitting a bigger capacitor and bingo - problem solved. The Library's chief engineer asked me to make a report as to what the original problem was. I said electro-magnetic radiation between the long coax cables that were run in close proximity. He nearly exploded at that "You can't say electro-magnetic radiation" he said "The whole place will walk out". So we agreed to just say interference.