james@bigtex.cactus.org (James Van Artsdalen) (10/30/88)
In <549@gt-eedsp.UUCP>, jensen@gt-eedsp.UUCP (P. Allen Jensen) wrote: > The reason was that "memory is reliable enough that the added cost > was not justified." If you have ever worked on some older equipment > without parity, your opinion may differ. Could an expert on RAM > chips respond ? Is memory really "reliable enough" ? I personally haven't found parity checking to be worthwhile. I have had three memory systems errors on machines that had parity checking, and only one of those errors was a chip. None of those systems reported parity errors until well after I had discovered or deduced the problem myself, and the Apple Lisa never reported an error. A large number of machines in the PC market effectively don't have parity checking. Many clones use Phoenix's BIOS, which has this habit of disabling NMI and hence parity error reporting. Microsoft's symdeb debugger also leaves NMI disabled. Many video cards do bizarre things to NMI too. For those not aware: the Intel 80x88 family has a design flaw that requires external hardware to disable NMI. Without such hardware it is not possible to prevent the system from randomly crashing when NMIs are used. -- James R. Van Artsdalen james@bigtex.cactus.org "Live Free or Die" Home: 512-346-2444 Work: 338-8789 9505 Arboretum Blvd Austin TX 78759