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From: umapd51@cc.ic.ac.uk (W.A.C. Mier-Jedrzejowicz)
Newsgroups: comp.sys.handhelds
Subject: Re: RAM (or ROM) card contents (was: Hidden EQ Library features)
Summary: Can a RAM chip corner be recovered?
Message-ID: <1991Jan17.032222.16870@cc.ic.ac.uk>
Date: 17 Jan 91 03:22:20 GMT
References: <1991Jan9.092526.23383@santra.uucp> <7360045@hpfcso.HP.COM>
Organization: Imperial College Computer Centre
Lines: 15
Nntp-Posting-Host: suni2cc


Ray Depew asks who is going to be next to follow up on Frank Wales'
comment about protecting memory from being overwritten. Well, I seem to
recall that HP-67/97 cards with a corner snipped could be write-enabled
by use of a special cut-down card with just a corner (the hardware
solution) and HP-41 cards with a corner clipped could be reused if flag
14 was set (the software solution). Logically, then, there should be a
liveware solution to HP48 RAM chips with the corner cut - stick your
finger on the cut-off corner! Hmmm - better ground yourself first.
Anyone else with a firm footing in reality and their feet on the ground
care to comment? (I suspect that there may be a quantum uncertainty
effect here - can you recover more memory than was lost in the first
place? ;-) ).
Wlodek Mier-Jedrzejowicz, Space and Atmospheric Physics, Imperial
College, London