---------------------------<snip>-------------------------
Real CCW addresses are also used by the documented EXCPVR interface. The
biggest problem with STARTIO is that there is no allocation, DCB, or
OPEN required. All it needs is an IOSB -- which contains pointers to the
channel program and UCB. Using STARTIO, you can construct a channel
program to read or write any records anywhere on any device. This puts
you one subtle programming error away from "wiping out" something
important that isn't yours. The other danger is having to write code
that executes in SRB mode -- with PSW key zero -- to manage I/O completion.
Without question, STARTIO is a dangerous interface -- made even more
dangerous by the total lack of documentation on its use.
------------------------<unsnip>----------------------
Given the potential risks, I think that I'll stick to EXCP with Format-1
CCW's. If this is going to be a public-domain program, I'd rather be
safe than sorry; and I don't want to give someone the rope they might
use to hang themselves. :-)
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