🚀 go-pugleaf

In article <1992Dec22.024303.1@cc.curtin.edu.au>, zrepachol@cc.curtin.edu.au writes:
=In article <1992Dec16.113301.977@cmkrnl.com>, jeh@cmkrnl.com writes:
=> Are you happy with the $QIO system service?  If you were building a new O/S
=> from scratch, would you make the "basic I/O call" that's available for 
=> non-privileged programs look like $QIO, or like something else?  If the latter,
=> what?  If you could specify a new I/O interface to supplement $QIO in VMS, what
=> would it look like?
=> 
=
=The change ?I would make is to buffer handling. On a read the OS would do what
=ever needs to be done to dump the data into mem, then fills in a pointer and
=size block and maps the lot to your address space. By trapping the page fault
=on a not yet mapped buffer pointer, the page fault code can put the PC into
=a wait state till IO completion clears the page fault condition. This would
=enable atomic asyncronous IO from the user code view.

Not meaning to be rude or insulting, I'd just like to point out to you tha I/O
processing of the sort you're talking about occurs at an IPL above ASTDEL. You
*DO* know what happens when you incur a page fault above ASTDEL, don't you?  So
you might be asking for a bigger change than you realize.

Or don't you know what a buffer overflow is, or how much the O/S would have to
be modified to "fix" buffer overflows?
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.