-----Original Message----- From: owner-cypherpunks@minder.net [mailto:owner-cypherpunks@minder.net]On Behalf Of An Metet Sent: Friday, July 16, 2004 6:35 AM To: cypherpunks@minder.net Subject: vacuum-safe laptops ?

Does anyone *know* (first or second hand, I can speculate myself) which laptops, if any, can safely go to zero air pressure (dropping from 1 atm to 0 in, say, 1 minute.)

What's your application, exactly? A rocket? I don't know about rapid decompression, but one problem is with the disk drives - the heads rely on entrained air to maintain separation from the disk surface. Most drives are not hermetically sealed, and have a (filtered) port to the outside to equalize air pressure. Some drives *are* sealed, and will operate at low pressure. I've seen this issue disscussed in the context of computers and laptops at high-altitude astronomical observatories: most machines will suffer head crashes if you try to use them at > 10,000 feet (jets maintain an internal pressure altitude of about 5,000 feet). Some applications use solid state drives to get around this: http://www.globalspec.com/featuredproducts/detail?exhibitId=10540&fromSpotlight=1&fromSupplier=0 Some displays may also be a problem. This is more an issue for big plasma displays. Sony makes a special plasma TV for high altitude use: http://www.superwarehouse.com/Sony_PlasmaPro_PFM-42V1A_S_Silver_42_Plasma_Di... A useful article is at http://www.iht.com/IHT/SUP/031999/digi-08.html You might want to look at the Itronix GoBook Max. http://www.gobookmax.com/ This device supposedly meets MILSPEC: http://www.dtc.army.mil/pdf/810.pdf which is a USG survivability spec. It includes an explosive decompression test, but not to high vacuum. ...and of course, all this gets pricy. Peter Trei