General TC11 DECtape diagnostic/formatter questions

Paul Koning paulkoning at
Wed Nov 9 20:18:47 CST 2016

> On Nov 9, 2016, at 5:57 PM, Josh Dersch <derschjo at> wrote:
> ...
> A quick update -- I ran the ZTCD diagnostics and they do fail, despite my
> recollection (this is what I get for not taking notes at the end of
> yesterday, and yesterday seems so far away now...).  The first test (a
> forward WALL, followed by an RALL of a single block) fails with the
> following spew (for example):
> BLKRQ 000310 DATA ERR  WORD 00054.  S/B 176376  WAS 104106
> Based on a reading of the fiche listing (which is a slightly newer revision
> of the binary I have) I believe S/B is the expected data and "WAS" is the
> read-back data for a given word.  Since one appears to be the obverse
> complement of the other, it looks like the obverse complement logic is
> running when it shouldn't be...

Yes, those two patterns are indeed obverse complement.  Word 0054?  That's odd, if it's doing this wrong for a word in the middle of the buffer.  Can you have it halt on fail so you can examine the buffer?


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