[TUHS] Card reader on Unix

Dave Horsfall dave at horsfall.org
Sun Dec 10 10:23:29 AEST 2017


Something's been bothering me for a while...  I've just remembered that 
our 11/40 with more peripherals than you could shake a stick at -- it had 
just about everything except a DECtape -- also had, so help me, a card 
reader!  As I dimly recall, 'twas a slow CDC (?) model; we didn't have it 
for long, either because it was on loan or because it was so unreliable, I 
simply don't remember.

Anyway, our driver handled it in two modes: you either got a raw image of 
each card (likely via DMA instead of column by column, but I could be 
wrong) i.e. 80 words with each column of 12 holes fitting nicely into a 
16-bit word, or there was a half-arsed attempt at converting EBCDIC to 
ASCII, with trailing blanks replaced by a newline (i.e. think of it as a 
line printer in reverse).  Or was it converting from whatever KRONOS used 
to ASCII?

Now, what I *distinctly* remember was writing two scripts: "/etc/cdc" and 
"/etc/dec" which switched between the two modes, quite likely by patching 
the in-core kernel!

I'd give a testicle to have that "CSU tape" back again (and no doubt so 
would Warren), but can anyone else remember this (or dare to call me a 
liar; yes, I'm still touchy about that)?  The snag is, towards the end of 
the CSU before they were about to be engulfed by the admin suits and 
forced to support payroll programs in COBOL etc, I was the only senior 
Unix bod left, so it's unlikely that the CSU source code followed someone 
else home...

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."


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