rcte2q@jetson.uh.edu (02/14/91)
The recent postings about light-induced bit changes has given me pause. I am an
impoverished student hacker, so I have been using 'appropriated' file folder
adhesive labels to cover my EPROM windows. My question: are all labels equal,
or are there reasons not to continue using thin, plain paper+adhesive labels?
-- Larry Liska,
Univ. of Houstonjgd@Dixie.Com (John G. DeArmond) (02/16/91)
rcte2q@jetson.uh.edu writes: >The recent postings about light-induced bit changes has given me pause. I am an >impoverished student hacker, so I have been using 'appropriated' file folder >adhesive labels to cover my EPROM windows. My question: are all labels equal, >or are there reasons not to continue using thin, plain paper+adhesive labels? Funny you'd mention it. I happened to be burning some EPROMS when I read your article and decided to test. A file label over a 27256 reduces the sensitivity to the same strobe as in the first test from about 15 feet to about 3 feet. I did not test again with the quartz-halogen lamp. For very cheap window covers, I suggest floppy disk write protect tabs. If you buy the kind of disks that use foil-based tabs, you can even write on them. If like me, you buy the el-cheapo bulk disks with the black vinyl tabs, simply stick the file label over the vinyl label. Or if you're REAL cheap, some Scotch 33+ electrical tape works well :-) John -- John De Armond, WD4OQC | "Purveyors of speed to the Trade" (tm) Rapid Deployment System, Inc. | Home of the Nidgets (tm) Marietta, Ga | {emory,uunet}!rsiatl!jgd |"Politically InCorrect.. And damn proud of it
billp@col.hp.com (Bill Pherigo) (02/18/91)
Disk write protect tabs with metal backing work best. All others I've tried didn't prevent faulty operation in direct sunlight. billp
thad@public.BTR.COM (Thaddeus P. Floryan) (02/18/91)
In article <5191@acorn.co.uk> agodwin@acorn.co.uk (Adrian Godwin) writes: >Look out for write-protect labels intended for 5.25" floppy discs - these >are often made of foil to ensure they will be properly detected by photosensors >in the disc drive. Do you mean "look out for" as in: 1) find them, buy them, and use them, or 2) toss them out the window and over the fence? :-) Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]
panek@hp-and.HP.COM (Jon Panek) (02/23/91)
In <8505.27b915d3@jetson.uh.edu>, Larry Liska writes > The recent postings about light-induced bit changes has given me pause. > I am an impoverished student hacker, so I have been using 'appropriated' > file folder adhesive labels to cover my EPROM windows. My question: > are all labels equal, or are there reasons not to continue using thin, > plain paper+adhesive labels? Here at Hewlett-Packard (Andover Division), we use EPROMs regularly to store microprocessor code in our medical products. We cover the quartz windows using standard, adhesive paper labels. As one responder noted, commercial users like to label their EPROMs by printing on the labels with a dot-matrix printer prior to covering the windows. These paper-based labels have proven completely reliable for use in medical products. Do note that these EPROMs are inside closed instruments, and probably never see the light of day. Moral: if your parts are lying on a bench, exposed to flourescent lights, etc, just let your random papers, databooks, schematics, manuals and sandwich wrappers cover them up. That works pretty well, too. Jonathan Panek Hewlett-Packard, Andover Division panek@hp-and.an.HP.COM (508) 687-1501 X-2866
thad@public.BTR.COM (Thaddeus P. Floryan) (02/24/91)
In article <13650003@hp-and.HP.COM> panek@hp-and.HP.COM (Jon Panek) writes: >Here at Hewlett-Packard (Andover Division), we use EPROMs regularly to >store microprocessor code in our medical products. We cover the quartz >windows using standard, adhesive paper labels. As one responder noted, >commercial users like to label their EPROMs by printing on the labels with >a dot-matrix printer prior to covering the windows. These paper-based >labels have proven completely reliable for use in medical products. Do >note that these EPROMs are inside closed instruments, and probably never >see the light of day. Precisely true! I have terminals from the late '70s whose code exists in paper-label-covered EPROMs which still work fine. One of my own company's products, since 1983, includes EPROMs shielded by paper labels on which version numbers were printed by a dot-matrix printer, and not ONE of those EPROMs has ever lost its data; to be fair, the circuitry containing the EPROMs is entombed in Pac-Tec plastic cases (thus no direct exposure to daylight or flourescent lighting). I don't know what would happen if we were to use transparent cases and the customer base included tanning salons, but ... :-) Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]
amichiel@rodan.acs.syr.edu (Allen J Michielsen) (02/25/91)
In article <13650003@hp-and.HP.COM> panek@hp-and.HP.COM (Jon Panek) writes: >In <8505.27b915d3@jetson.uh.edu>, Larry Liska writes >> The recent postings about light-induced bit changes has given me pause. >>... I have been using file folder adhesive labels to cover EPROM windows. >> are all labels equal, or are there reasons not to continue using thin, >... These paper-based labels have proven completely reliable... >...these EPROMs are inside closed instruments, >Moral: if your parts are lying on a bench, exposed to flourescent lights, > etc, just let your random papers, databooks, schematics, manuals and > sandwich wrappers cover them up. That works pretty well, too. I've been following this rambling discussion from a distance. I too have heard the stories about trade show 'zaps' and don't doubt it's possibility. I do doubt (somehow) the 'reality' of the posts in regards to people who have claims to light power and frequency exposure measurements, as a 'hobby' experiment. The story I'll regale is quite the opposite. I changed dept's at my current employer 5 years ago. For 1 setup, they have a programmable experimental logic 'trainer' (a little microprocessor setup with software & i/o capabilities) used to teach by example real world analog and digital i/o and programming as it might be used for typical engineering control problems (tanks level control, automated machine control, conveyer system control...). This little thing sits on top of a bench and has all of it's cirtuitry exposed for further educational reasons. The bios software is contained in 4 16Kx1 (2716) roms. At that time, this thing was 4 years old. I was mortified to see that NONE of the roms have ANY covers on them at all for even further 'educationa emphasis'. This box is in a low ceiling room, with typical fluorscent lights that remain on 24 hours a day, 7 days a week, 52 weeks a year. These roms have been exposed to this for a total of 9 years now, and none of them have had a single problem. I'll open my door if anybody wishes to make a independant 'site inspection' because I don't believe it either, and I see it every day. Besides that, once a year the lab and equipment is used as photographic props for publication materials, and they do use flashes and reflectors.... I also will quickly add that when I program a chip, I NEVER leave it exposed like that (unless instructed to). I find it hard to believe that ANY rom that is put in a finished product would EVER have a reasonable expectancy to get enough uv light to cause problems. al -- Al. Michielsen, Mechanical & Aerospace Engineering, Syracuse University InterNet: amichiel@rodan.acs.syr.edu amichiel@sunrise.acs.syr.edu Bitnet: AMICHIEL@SUNRISE